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SubjectRe: [PATCH] dmaengine: at_hdmac: new driver for the Atmel AHB DMA Controller
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Date

On Fri, 2008-10-17 at 08:43 -0700, Nicolas Ferre wrote:
> This AHB DMA Controller (aka HDMA or DMAC on AT91 systems) is availlable on
> at91sam9rl chip. It will be used on other products in the future.
>
> This first release covers only the memory-to-memory tranfer type. This is the
> only tranfer type supported by this chip.
> On other products, it will be used also for peripheral DMA transfer (slave API
> support to come).
>
> I used dmatest client without problem in different configurations to test
> it.
>
> Full documentation for this controller can be found in the SAM9RL datasheet :
> http://www.atmel.com/dyn/products/product_card.asp?part_id=4243
>
> Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
> ---

Hi Nicolas,

A few comments below.

Also, checkpatch reported:

total: 4 errors, 45 warnings, 1475 lines checked

...mostly 80 column warnings (some you may want to take a look at).


Regards,
Dan

> arch/arm/mach-at91/at91sam9rl_devices.c | 47 ++
> drivers/dma/Kconfig | 8 +
> drivers/dma/Makefile | 1 +
> drivers/dma/at_hdmac.c | 989 +++++++++++++++++++++++++++++++
> drivers/dma/at_hdmac_regs.h | 377 ++++++++++++
> include/linux/at_hdmac.h | 26 +

...this header should be moved somewhere under arch/arm/include.

> 6 files changed, 1448 insertions(+), 0 deletions(-)
>
> diff --git a/arch/arm/mach-at91/at91sam9rl_devices.c b/arch/arm/mach-at91/at91sam9rl_devices.c
> index 87deb1e..ad596ff 100644
> --- a/arch/arm/mach-at91/at91sam9rl_devices.c
> +++ b/arch/arm/mach-at91/at91sam9rl_devices.c
> @@ -9,6 +9,7 @@
> #include <asm/mach/arch.h>
> #include <asm/mach/map.h>
>
> +#include <linux/at_hdmac.h>
> #include <linux/dma-mapping.h>
> #include <linux/platform_device.h>
> #include <linux/i2c-gpio.h>
> @@ -26,6 +27,51 @@
>
>
> /* --------------------------------------------------------------------
> + * HDMAC - AHB DMA Controller
> + * -------------------------------------------------------------------- */
> +
> +#if defined(CONFIG_AT_HDMAC) || defined(CONFIG_AT_HDMAC_MODULE)
> +static u64 hdmac_dmamask = DMA_BIT_MASK(32);
> +
> +static struct at_dma_platform_data atdma_pdata = {
> + .nr_channels = 2,
> +};
> +
> +static struct resource hdmac_resources[] = {
> + [0] = {
> + .start = AT91_BASE_SYS + AT91_DMA,
> + .end = AT91_BASE_SYS + AT91_DMA + SZ_512 - 1,
> + .flags = IORESOURCE_MEM,
> + },
> + [2] = {
> + .start = AT91SAM9RL_ID_DMA,
> + .end = AT91SAM9RL_ID_DMA,
> + .flags = IORESOURCE_IRQ,
> + },
> +};
> +
> +static struct platform_device at_hdmac_device = {
> + .name = "at_hdmac",
> + .id = -1,
> + .dev = {
> + .dma_mask = &hdmac_dmamask,
> + .coherent_dma_mask = DMA_BIT_MASK(32),
> + .platform_data = &atdma_pdata,
> + },
> + .resource = hdmac_resources,
> + .num_resources = ARRAY_SIZE(hdmac_resources),
> +};
> +
> +void __init at91_add_device_hdmac(void)
> +{
> + dma_cap_set(DMA_MEMCPY, atdma_pdata.cap_mask);
> + platform_device_register(&at_hdmac_device);
> +}
> +#else
> +void __init at91_add_device_hdmac(void) {}
> +#endif
> +
> +/* --------------------------------------------------------------------
> * USB HS Device (Gadget)
> * -------------------------------------------------------------------- */
>
> @@ -1114,6 +1160,7 @@ void __init at91_add_device_serial(void) {}
> */
> static int __init at91_add_standard_devices(void)
> {
> + at91_add_device_hdmac();
> at91_add_device_rtc();
> at91_add_device_rtt();
> at91_add_device_watchdog();
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index cd30390..03bfd8f 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -47,6 +47,14 @@ config DW_DMAC
> Support the Synopsys DesignWare AHB DMA controller. This
> can be integrated in chips such as the Atmel AT32ap7000.
>
> +config AT_HDMAC
> + tristate "Atmel AHB DMA support"
> + depends on ARCH_AT91 && ARCH_AT91SAM9RL
> + select DMA_ENGINE
> + help
> + Support the Atmel AHB DMA controller. This can be integrated in
> + chips such as the Atmel AT91SAM9RL.
> +
> config FSL_DMA
> bool "Freescale MPC85xx/MPC83xx DMA support"
> depends on PPC
> diff --git a/drivers/dma/Makefile b/drivers/dma/Makefile
> index 14f5952..9c8ce35 100644
> --- a/drivers/dma/Makefile
> +++ b/drivers/dma/Makefile
> @@ -7,3 +7,4 @@ obj-$(CONFIG_INTEL_IOP_ADMA) += iop-adma.o
> obj-$(CONFIG_FSL_DMA) += fsldma.o
> obj-$(CONFIG_MV_XOR) += mv_xor.o
> obj-$(CONFIG_DW_DMAC) += dw_dmac.o
> +obj-$(CONFIG_AT_HDMAC) += at_hdmac.o
> diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c
> new file mode 100644
> index 0000000..2f0a386
> --- /dev/null
> +++ b/drivers/dma/at_hdmac.c
> @@ -0,0 +1,989 @@
> +/*
> + * Driver for the Atmel AHB DMA Controller (aka HDMA or DMAC on AT91 systems)
> + *
> + * Copyright (C) 2008 Atmel Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + *
> + *
> + * This supports the Atmel AHB DMA Controller,
> + *
> + * The driver has currently been tested with the Atmel AT91SAM9RL
> + * and AT91SAM9M10.
> + */
> +
> +#include <linux/clk.h>
> +#include <linux/dmaengine.h>
> +#include <linux/dma-mapping.h>
> +#include <linux/dmapool.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/platform_device.h>
> +
> +#include "at_hdmac_regs.h"
> +
> +/*
> + * Glossary
> + * --------
> + *
> + * at_hdmac : Name of the ATmel AHB DMA Controller
> + * at_dma_ / atdma : ATmel DMA controller entity related
> + * atc_ / atchan : ATmel DMA Channel entity related
> + */
> +
> +#define ATC_DEFAULT_CFG (ATC_FIFOCFG_HALFFIFO)
> +#define ATC_DEFAULT_CTRLA (0)
> +#define ATC_DEFAULT_CTRLB ( ATC_SIF(0) \
> + | ATC_DIF(1))
> +
> +/*
> + * Initial number of descriptors to allocate for each channel. This could
> + * be increased of this amount during dma usage.
> + */
> +#define INIT_NR_DESCS_PER_CHANNEL 16
> +
> +/* prototypes */
> +static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx);
> +
> +
> +/*----------------------------------------------------------------------*/
> +
> +static struct at_desc *atc_first_active(struct at_dma_chan *atchan)
> +{
> + return list_first_entry(&atchan->active_list, struct at_desc, desc_node);
> +}
> +
> +static struct at_desc *atc_first_queued(struct at_dma_chan *atchan)
> +{
> + return list_first_entry(&atchan->queue, struct at_desc, desc_node);
> +}
> +
> +/**
> + * atc_alloc_descriptor - allocate and return an initilized descriptor
> + * @chan: the channel to allocate descriptors for
> + * @gfp_flags: GFP allocation flags
> + */
> +static struct at_desc *atc_alloc_descriptor(struct dma_chan *chan,
> + gfp_t gfp_flags)
> +{
> + struct at_desc *desc = NULL;
> + struct at_dma *atdma = to_at_dma(chan->device);
> + dma_addr_t phys;
> +
> + desc = dma_pool_alloc(atdma->dma_desc_pool, gfp_flags, &phys);
> + if (desc) {
> + BUG_ON(phys & 0x3UL); /* descriptors have to be word aligned */

hmm, yes this is a bug but can't we trust that dma_pool_alloc does its
job correctly?

> + memset(desc, 0, sizeof(struct at_desc));
> + dma_async_tx_descriptor_init(&desc->txd, chan);
> + async_tx_ack(&desc->txd);

the DMA_CTRL_ACK bit is under control of the client. It should be
read-only to the driver (except for extra descriptors that the driver
creates on behalf of the client).

> + desc->txd.tx_submit = atc_tx_submit;
> + INIT_LIST_HEAD(&desc->txd.tx_list);
> + desc->txd.phys = phys;
> + }
> +
> + return desc;
> +}
> +
> +/**
> + * atc_desc_get - get a unsused descriptor from free_list
> + * @atchan: channel we want a new descriptor for
> + */
> +static struct at_desc *atc_desc_get(struct at_dma_chan *atchan)
> +{
> + struct at_desc *desc, *_desc;
> + struct at_desc *ret = NULL;
> + unsigned int i = 0;
> + LIST_HEAD(tmp_list);
> +
> + spin_lock_bh(&atchan->lock);
> + list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {
> + if (async_tx_test_ack(&desc->txd)) {
> + list_del(&desc->desc_node);
> + ret = desc;
> + break;
> + }
> + dev_dbg(&atchan->chan_common.dev, "desc %p not ACKed\n", desc);
> + i++;
> + }
> + spin_unlock_bh(&atchan->lock);
> +
> + dev_vdbg(&atchan->chan_common.dev, "scanned %u descriptors on freelist\n", i);
> +
> + /* no more descriptor available in initial pool : create some more */
> + if (!ret) {
> + for (i = 0; i < INIT_NR_DESCS_PER_CHANNEL; i++) {
> + desc = atc_alloc_descriptor(&atchan->chan_common, GFP_KERNEL);
> + if (!desc)
> + break;
> + /* return first descripor, queue others in free_list */

sp: descriptor

> + if (i)
> + list_add_tail(&desc->desc_node, &tmp_list);
> + else
> + ret = desc;
> + }
> +
> + spin_lock_bh(&atchan->lock);
> + atchan->descs_allocated += i;
> + list_splice(&tmp_list, &atchan->free_list);
> + spin_unlock_bh(&atchan->lock);
> + }
> +
> + return ret;
> +}
> +
> +/**
> + * atc_desc_put - move a descriptor, including any children, to the free list
> + * @atchan: channel we work on
> + * @desc: descriptor, at the head of a chain, to move to free list
> + */
> +static void atc_desc_put(struct at_dma_chan *atchan, struct at_desc *desc)
> +{
> + if (desc) {
> + struct at_desc *child;
> +
> + spin_lock_bh(&atchan->lock);
> + list_for_each_entry(child, &desc->txd.tx_list, desc_node)
> + dev_vdbg(&atchan->chan_common.dev,
> + "moving child desc %p to freelist\n",
> + child);
> + list_splice_init(&desc->txd.tx_list, &atchan->free_list);
> + dev_vdbg(&atchan->chan_common.dev, "moving desc %p to freelist\n", desc);
> + list_add(&desc->desc_node, &atchan->free_list);
> + spin_unlock_bh(&atchan->lock);
> + }
> +}
> +
> +/**
> + * atc_assign_cookie - compute and assign new cookie
> + * @atchan: channel we work on
> + * @desc: descriptor to asign cookie for
> + *
> + * Called with atchan->lock held and bh disabled
> + */
> +static dma_cookie_t
> +atc_assign_cookie(struct at_dma_chan *atchan, struct at_desc *desc)
> +{
> + dma_cookie_t cookie = atchan->chan_common.cookie;
> +
> + if (++cookie < 0)
> + cookie = 1;
> +
> + atchan->chan_common.cookie = cookie;
> + desc->txd.cookie = cookie;
> +
> + return cookie;
> +}
> +
> +/**
> + * atc_dostart - starts the DMA engine for real
> + * @atchan: the channel we want to start
> + * @first: first descriptor in the list we want to begin with
> + *
> + * Called with atchan->lock held and bh disabled
> + */
> +static void atc_dostart(struct at_dma_chan *atchan, struct at_desc *first)
> +{
> + struct at_dma *atdma = to_at_dma(atchan->chan_common.device);
> +
> + /* ASSERT: channel is idle */
> + if (atc_chan_is_enabled(atchan)) {
> + dev_err(&atchan->chan_common.dev,
> + "BUG: Attempted to start non-idle channel\n");
> + dev_err(&atchan->chan_common.dev,
> + " channel: s0x%x d0x%x ctrl0x%x:0x%x l0x%x\n",
> + channel_readl(atchan, SADDR),
> + channel_readl(atchan, DADDR),
> + channel_readl(atchan, CTRLA),
> + channel_readl(atchan, CTRLB),
> + channel_readl(atchan, DSCR));
> +
> + /* The tasklet will hopefully advance the queue... */
> + return;
> + }
> +
> + vdbg_dump_regs(atchan);
> +
> + /* clear any pending interrupt */
> + while (dma_readl(atdma, EBCISR))
> + cpu_relax();
> +
> + channel_writel(atchan, SADDR, 0);
> + channel_writel(atchan, DADDR, 0);
> + channel_writel(atchan, CTRLA, 0);
> + channel_writel(atchan, CTRLB, 0);
> + channel_writel(atchan, DSCR, first->txd.phys);
> + dma_writel(atdma, CHER, atchan->mask);
> +
> + vdbg_dump_regs(atchan);
> +}
> +
> +/**
> + * atc_chain_complete - finish work for one transaction chain
> + * @atchan: channel we work on
> + * @desc: descriptor at the head of the chain we want do complete
> + *
> + * Called with atchan->lock held and bh disabled */
> +static void
> +atc_chain_complete(struct at_dma_chan *atchan, struct at_desc *desc)
> +{
> + dma_async_tx_callback callback;
> + void *param;
> + struct dma_async_tx_descriptor *txd = &desc->txd;
> +
> + dev_vdbg(&atchan->chan_common.dev, "descriptor %u complete\n", txd->cookie);
> +
> + atchan->completed_cookie = txd->cookie;
> + callback = txd->callback;
> + param = txd->callback_param;
> +
> + /* move children to free_list */
> + list_splice_init(&txd->tx_list, &atchan->free_list);
> + /* move myself to free_list */
> + list_move(&desc->desc_node, &atchan->free_list);
> +
> + /*
> + * We use dma_unmap_page() regardless of how the buffers were
> + * mapped before they were submitted...
> + */
> + if (!(txd->flags & DMA_COMPL_SKIP_DEST_UNMAP))
> + dma_unmap_page(atchan->chan_common.dev.parent, desc->lli.daddr, desc->len,
> + DMA_FROM_DEVICE);
> + if (!(txd->flags & DMA_COMPL_SKIP_SRC_UNMAP))
> + dma_unmap_page(atchan->chan_common.dev.parent, desc->lli.saddr, desc->len,
> + DMA_TO_DEVICE);
> +
> + /*
> + * The API requires that no submissions are done from a
> + * callback, so we don't need to drop the lock here
> + */
> + if (callback)
> + callback(param);
> +}
> +
> +/**
> + * atc_complete_all - finish work for all transactions
> + * @atchan: channel to complete transactions for
> + *
> + * Eventually submit queued descriptors if any
> + *
> + * Assume channel is idle while calling this function
> + * Called with atchan->lock held and bh disabled
> + */
> +static void atc_complete_all(struct at_dma_chan *atchan)
> +{
> + struct at_desc *desc, *_desc;
> + LIST_HEAD(list);
> +
> + dev_vdbg(&atchan->chan_common.dev, "complete all\n");
> +
> + BUG_ON(atc_chan_is_enabled(atchan));
> +
> + /*
> + * Submit queued descriptors ASAP, i.e. before we go through
> + * the completed ones.
> + */
> + if (!list_empty(&atchan->queue))
> + atc_dostart(atchan, atc_first_queued(atchan));
> + /* empty active_list now it is completed */
> + list_splice_init(&atchan->active_list, &list);
> + /* empty queue list by moving descriptors (if any) to active_list */
> + list_splice_init(&atchan->queue, &atchan->active_list);
> +
> + list_for_each_entry_safe(desc, _desc, &list, desc_node)
> + atc_chain_complete(atchan, desc);
> +}
> +
> +/**
> + * atc_cleanup_descriptors - cleanup up finished descriptors in active_list
> + * @atchan: channel to be cleaned up
> + *
> + * Called with atchan->lock held and bh disabled
> + */
> +static void atc_cleanup_descriptors(struct at_dma_chan *atchan)
> +{
> + struct at_desc *desc, *_desc;
> + struct at_desc *child;
> +
> + dev_vdbg(&atchan->chan_common.dev, "cleanup descriptors\n");
> +
> + list_for_each_entry_safe(desc, _desc, &atchan->active_list, desc_node) {
> + if (!(desc->lli.ctrla & ATC_DONE))
> + /* This one is currently in progress */
> + return;
> +
> + list_for_each_entry(child, &desc->txd.tx_list, desc_node)
> + if (!(child->lli.ctrla & ATC_DONE))
> + /* Currently in progress */
> + return;
> +
> + /*
> + * No descriptors so far seem to be in progress, i.e.
> + * this chain must be done.
> + */
> + atc_chain_complete(atchan, desc);
> + }
> +}
> +
> +/**
> + * atc_advance_work - at the end of a transaction, move forward
> + * @atchan: channel where the transaction ended
> + *
> + * Called with atchan->lock held and bh disabled
> + */
> +static void atc_advance_work(struct at_dma_chan *atchan)
> +{
> + dev_vdbg(&atchan->chan_common.dev, "advance_work\n");
> +
> + if ( list_empty(&atchan->active_list)
> + || list_is_singular(&atchan->active_list)) {
> + atc_complete_all(atchan);
> + } else {
> + atc_chain_complete(atchan, atc_first_active(atchan));
> + /* advance work */
> + atc_dostart(atchan, atc_first_active(atchan));
> + }
> +}
> +
> +
> +/**
> + * atc_handle_error - handle errors reported by DMA controller
> + * @atchan: channel where error occurs
> + *
> + * Called with atchan->lock held and bh disabled
> + */
> +static void atc_handle_error(struct at_dma_chan *atchan)
> +{
> + struct at_desc *bad_desc;
> + struct at_desc *child;
> +
> + /*
> + * The descriptor currently at the head of the active list is
> + * broked. Since we don't have any way to report errors, we'll
> + * just have to scream loudly and try to carry on.
> + */
> + bad_desc = atc_first_active(atchan);
> + list_del_init(&bad_desc->desc_node);
> +
> + /* As we are stopped, take advantage to push queued descriptors
> + * in active_list */
> + list_splice_init(&atchan->queue, atchan->active_list.prev);
> +
> + /* Try to restart the controller */
> + if (!list_empty(&atchan->active_list))
> + atc_dostart(atchan, atc_first_active(atchan));
> +
> + /*
> + * KERN_CRITICAL may seem harsh, but since this only happens
> + * when someone submits a bad physical address in a
> + * descriptor, we should consider ourselves lucky that the
> + * controller flagged an error instead of scribbling over
> + * random memory locations.
> + */
> + dev_crit(&atchan->chan_common.dev,
> + "Bad descriptor submitted for DMA!\n");
> + dev_crit(&atchan->chan_common.dev,
> + " cookie: %d\n", bad_desc->txd.cookie);
> + atc_dump_lli(atchan, &bad_desc->lli);
> + list_for_each_entry(child, &bad_desc->txd.tx_list, desc_node)
> + atc_dump_lli(atchan, &child->lli);
> +
> + /* Pretend the descriptor completed successfully */
> + atc_chain_complete(atchan, bad_desc);
> +}
> +
> +
> +/*-- IRQ & Tasklet ---------------------------------------------------*/
> +
> +static void atc_tasklet(unsigned long data)
> +{
> + struct at_dma_chan *atchan = (struct at_dma_chan *)data;
> +
> + /* Channel cannot be enabled here */
> + if (atc_chan_is_enabled(atchan)) {
> + dev_err(&atchan->chan_common.dev,
> + "BUG: channel enabled in tasklet\n");
> + return;
> + }
> +
> + spin_lock(&atchan->lock);
> + if (test_and_clear_bit(0, &atchan->error_status))
> + atc_handle_error(atchan);
> + else
> + atc_advance_work(atchan);
> +
> + spin_unlock(&atchan->lock);
> +}
> +
> +static irqreturn_t at_dma_interrupt(int irq, void *dev_id)
> +{
> + struct at_dma *atdma = (struct at_dma *)dev_id;
> + struct at_dma_chan *atchan;
> + int i;
> + u32 status, pending, imr;
> + int ret = IRQ_NONE;
> +
> + do {
> + imr = dma_readl(atdma, EBCIMR);
> + status = dma_readl(atdma, EBCISR);
> + pending = status & imr;
> +
> + if (!pending)
> + break;
> +
> + dev_vdbg(atdma->dma_common.dev,
> + "interrupt: status = 0x%08x, 0x%08x, 0x%08x\n",
> + status, imr, pending);
> +
> + for (i = 0; i < atdma->dma_common.chancnt; i++) {
> + atchan = &atdma->chan[i];
> + if (pending & (AT_DMA_CBTC(i) | AT_DMA_ERR(i))) {
> + if (pending & AT_DMA_ERR(i)) {
> + /*
> + spin_lock(atchan->lock);
> + atchan->error_status = 1;
> + spin_unlock(atchan->lock);

writing to an unsigned long should already be atomic, no?

> + */
> + /* Disable channel on AHB error */
> + dma_writel(atdma, CHDR, atchan->mask);
> + /* Give information to tasklet */
> + set_bit(0, &atchan->error_status);
> + }
> + tasklet_schedule(&atchan->tasklet);
> + ret = IRQ_HANDLED;
> + }
> + }
> +
> + } while (pending);
> +
> + return ret;
> +}
> +
> +
> +/*-- DMA Engine API --------------------------------------------------*/
> +
> +/**
> + * atc_tx_submit - set the prepared descriptor(s) to be executed by the engine
> + * @desc: descriptor at the head of the transaction chain
> + *
> + * Queue chain if DMA engine is working already
> + *
> + * Cookie increment and adding to active_list or queue must be atomic
> + */
> +static dma_cookie_t atc_tx_submit(struct dma_async_tx_descriptor *tx)
> +{
> + struct at_desc *desc = txd_to_at_desc(tx);
> + struct at_dma_chan *atchan = to_at_dma_chan(tx->chan);
> + dma_cookie_t cookie;
> +
> + spin_lock_bh(&atchan->lock);
> + cookie = atc_assign_cookie(atchan, desc);
> +
> + if (list_empty(&atchan->active_list)) {
> + dev_vdbg(&tx->chan->dev, "tx_submit: started %u\n",
> + desc->txd.cookie);
> + atc_dostart(atchan, desc);
> + list_add_tail(&desc->desc_node, &atchan->active_list);
> + } else {
> + dev_vdbg(&tx->chan->dev, "tx_submit: queued %u\n",
> + desc->txd.cookie);
> + list_add_tail(&desc->desc_node, &atchan->queue);
> + }
> +
> + spin_unlock_bh(&atchan->lock);
> +
> + return cookie;
> +}
> +
> +/**
> + * atc_prep_dma_memcpy - prepare a memcpy operation
> + * @chan: the channel to prepare operation on
> + * @dest: operation virtual destination address
> + * @src: operation virtual source address
> + * @len: operation length
> + * @flags: tx descriptor status flags
> + */
> +static struct dma_async_tx_descriptor *
> +atc_prep_dma_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
> + size_t len, unsigned long flags)
> +{
> + struct at_dma_chan *atchan = to_at_dma_chan(chan);
> + struct at_desc *desc = NULL;
> + struct at_desc *first = NULL;
> + struct at_desc *prev = NULL;
> + size_t xfer_count;
> + size_t offset;
> + unsigned int src_width;
> + unsigned int dst_width;
> + u32 ctrla;
> + u32 ctrlb;
> +
> + dev_vdbg(&chan->dev, "prep_dma_memcpy: d0x%x s0x%x l0x%zx f0x%lx\n",
> + dest, src, len, flags);
> +
> + if (unlikely(!len)) {
> + dev_dbg(&chan->dev, "prep_dma_memcpy: length is zero!\n");
> + return NULL;
> + }
> +
> + ctrla = ATC_DEFAULT_CTRLA;
> + ctrlb = ATC_DEFAULT_CTRLB
> + | ATC_SRC_ADDR_MODE_INCR
> + | ATC_DST_ADDR_MODE_INCR
> + | ATC_FC_MEM2MEM;
> +
> + /*
> + * We can be a lot more clever here, but this should take care
> + * of the most common optimization.
> + */
> + if (!((src | dest | len) & 3)) {
> + ctrla |= ATC_SRC_WIDTH_WORD | ATC_DST_WIDTH_WORD;
> + src_width = dst_width = 2;
> + } else if (!((src | dest | len) & 1)) {
> + ctrla |= ATC_SRC_WIDTH_HALFWORD | ATC_DST_WIDTH_HALFWORD;
> + src_width = dst_width = 1;
> + } else {
> + ctrla |= ATC_SRC_WIDTH_BYTE | ATC_DST_WIDTH_BYTE;
> + src_width = dst_width = 0;
> + }
> +
> + for (offset = 0; offset < len; offset += xfer_count << src_width) {
> + xfer_count = min_t(size_t, (len - offset) >> src_width,
> + ATC_BTSIZE_MAX);
> +
> + desc = atc_desc_get(atchan);
> + if (!desc)
> + goto err_desc_get;
> +
> + desc->lli.saddr = src + offset;
> + desc->lli.daddr = dest + offset;
> + desc->lli.ctrla = ctrla | xfer_count;
> + desc->lli.ctrlb = ctrlb;
> +
> + desc->txd.cookie = 0;
> + async_tx_ack(&desc->txd);
> +
> + if (!first) {
> + first = desc;
> + } else {
> + /* inform the HW lli about chaining */
> + prev->lli.dscr = desc->txd.phys;
> + /* insert the link descriptor to the LD ring */
> + list_add_tail(&desc->desc_node,
> + &first->txd.tx_list);
> + }
> + prev = desc;
> + }
> +
> + /* First descriptor of the chain embedds additional information */
> + first->txd.flags = flags; /* client is in control of this ack */
> + first->txd.cookie = -EBUSY;
> + first->len = len;
> +
> + /* set end-of-link to the last link descriptor of list*/
> + set_desc_eol(desc);
> +
> + return &first->txd;
> +
> +err_desc_get:
> + atc_desc_put(atchan, first);
> + return NULL;
> +}
> +
> +/**
> + * atc_is_tx_complete - poll for transaction completion
> + * @chan: DMA channel
> + * @cookie: transaction identifier to check status of
> + * @done: if not %NULL, updated with last completed transaction
> + * @used: if not %NULL, updated with last used transaction
> + *
> + * If @done and @used are passed in, upon return they reflect the driver
> + * internal state and can be used with dma_async_is_complete() to check
> + * the status of multiple cookies without re-checking hardware state.
> + */
> +static enum dma_status
> +atc_is_tx_complete(struct dma_chan *chan,
> + dma_cookie_t cookie,
> + dma_cookie_t *done, dma_cookie_t *used)
> +{
> + struct at_dma_chan *atchan = to_at_dma_chan(chan);
> + dma_cookie_t last_used;
> + dma_cookie_t last_complete;
> + enum dma_status ret;
> +
> + dev_vdbg(&chan->dev, "is_tx_complete: %d (d%d, u%d)\n",
> + cookie, done ? *done : 0, used ? *used : 0);
> +
> + spin_lock_bh(atchan->lock);
> +
> + last_complete = atchan->completed_cookie;
> + last_used = chan->cookie;
> +
> + ret = dma_async_is_complete(cookie, last_complete, last_used);
> + if (ret != DMA_SUCCESS) {
> + atc_cleanup_descriptors(atchan);
> +
> + last_complete = atchan->completed_cookie;
> + last_used = chan->cookie;
> +
> + ret = dma_async_is_complete(cookie, last_complete, last_used);
> + }
> +
> + spin_unlock_bh(atchan->lock);
> +
> + if (done)
> + *done = last_complete;
> + if (used)
> + *used = last_used;
> +
> + return ret;
> +}
> +
> +/**
> + * atc_issue_pending - try to finish work
> + * @chan: target DMA channel
> + */
> +static void atc_issue_pending(struct dma_chan *chan)
> +{
> + struct at_dma_chan *atchan = to_at_dma_chan(chan);
> +
> + dev_vdbg(&chan->dev, "issue_pending\n");
> +
> + if (!atc_chan_is_enabled(atchan)) {
> + spin_lock_bh(&atchan->lock);
> + atc_advance_work(atchan);
> + spin_unlock_bh(&atchan->lock);
> + }
> +}
> +
> +/**
> + * atc_alloc_chan_resources - allocate resources for DMA channel
> + * @chan: allocate descriptor resources for this channel
> + * @client: current client requesting the channel be ready for requests
> + *
> + * return - the number of allocated descriptors
> + */
> +static int atc_alloc_chan_resources(struct dma_chan *chan,
> + struct dma_client *client)
> +{
> + struct at_dma_chan *atchan = to_at_dma_chan(chan);
> + struct at_dma *atdma = to_at_dma(chan->device);
> + struct at_desc *desc;
> + int i;
> + LIST_HEAD(tmp_list);
> +
> + dev_vdbg(&chan->dev, "alloc_chan_resources\n");
> +
> + /* ASSERT: channel is idle */
> + if (atc_chan_is_enabled(atchan)) {
> + dev_dbg(&chan->dev, "DMA channel not idle ?\n");
> + return -EIO;
> + }
> +
> + /* have we already been set up? */
> + if (!list_empty(&atchan->free_list))
> + return atchan->descs_allocated;
> +
> + /* Allocate initial pool of descriptors */
> + for (i = 0; i < INIT_NR_DESCS_PER_CHANNEL; i++) {
> + desc = atc_alloc_descriptor(chan, GFP_KERNEL);
> + if (!desc) {
> + dev_err(atdma->dma_common.dev,
> + "Only %d initial descriptors\n", i);
> + break;
> + }
> + list_add_tail(&desc->desc_node, &tmp_list);
> + }
> +
> + spin_lock_bh(&atchan->lock);
> + atchan->descs_allocated = i;
> + list_splice(&tmp_list, &atchan->free_list);
> + atchan->completed_cookie = chan->cookie = 1;
> + spin_unlock_bh(&atchan->lock);
> +
> + /* channel parameters */
> + channel_writel(atchan, CFG, ATC_DEFAULT_CFG);
> +
> + tasklet_init(&atchan->tasklet, atc_tasklet, (unsigned long)atchan);

This routine may be called while the channel is already active,
potentially causing tasklet_init() to be called while a tasklet is
pending. Can this move to at_dma_probe()?

> + /* clear any pending interrupt */
> + while (dma_readl(atdma, EBCISR))
> + cpu_relax();
> + atc_enable_irq(atchan);

ditto.

> +
> + dev_dbg(&chan->dev,
> + "alloc_chan_resources: allocated %d descriptors\n",
> + atchan->descs_allocated);
> +
> + return atchan->descs_allocated;
> +}
> +
> +/**
> + * atc_free_chan_resources - free all channel resources
> + * @chan: DMA channel
> + */
> +static void atc_free_chan_resources(struct dma_chan *chan)
> +{
> + struct at_dma_chan *atchan = to_at_dma_chan(chan);
> + struct at_dma *atdma = to_at_dma(chan->device);
> + struct at_desc *desc, *_desc;
> + LIST_HEAD(list);
> +
> + dev_dbg(&chan->dev, "free_chan_resources: (descs allocated=%u)\n",
> + atchan->descs_allocated);
> +
> + /* ASSERT: channel is idle */
> + BUG_ON(!list_empty(&atchan->active_list));
> + BUG_ON(!list_empty(&atchan->queue));
> + BUG_ON(atc_chan_is_enabled(atchan));
> +
> + /* Disable interrupts */
> + atc_disable_irq(atchan);
> + tasklet_disable(&atchan->tasklet);
> +
> + list_for_each_entry_safe(desc, _desc, &atchan->free_list, desc_node) {
> + dev_vdbg(&chan->dev, " freeing descriptor %p\n", desc);
> + list_del(&desc->desc_node);
> + /* free link descriptor */
> + dma_pool_free(atdma->dma_desc_pool, desc, desc->txd.phys);
> + }
> + list_splice_init(&atchan->free_list, &list);
> + atchan->descs_allocated = 0;
> +
> + dev_vdbg(&chan->dev, "free_chan_resources: done\n");
> +}
> +
> +
> +/*-- Module Management -----------------------------------------------*/
> +
> +/**
> + * at_dma_off - disable DMA controller
> + * @atdma: the Atmel HDAMC device
> + */
> +static void at_dma_off(struct at_dma *atdma)
> +{
> + dma_writel(atdma, EN, 0);
> +
> + /* disable all interrupts */
> + dma_writel(atdma, EBCIDR, -1L);
> +
> + /* confirm that all channels are disabled */
> + while (dma_readl(atdma, CHSR) & atdma->all_chan_mask)
> + cpu_relax();
> +}
> +
> +static int __init at_dma_probe(struct platform_device *pdev)
> +{
> + struct at_dma_platform_data *pdata;
> + struct resource *io;
> + struct at_dma *atdma;
> + size_t size;
> + int irq;
> + int err;
> + int i;
> +
> + /* get DMA Controller parameters from platform */
> + pdata = pdev->dev.platform_data;
> + if (!pdata || pdata->nr_channels > AT_DMA_MAX_NR_CHANNELS)
> + return -EINVAL;
> +
> + io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!io)
> + return -EINVAL;
> +
> + irq = platform_get_irq(pdev, 0);
> + if (irq < 0)
> + return irq;
> +
> + size = sizeof(struct at_dma);
> + size += pdata->nr_channels * sizeof(struct at_dma_chan);
> + atdma = kzalloc(size, GFP_KERNEL);
> + if (!atdma)
> + return -ENOMEM;
> +
> + /* discover transaction capabilites from the platform data */
> + atdma->dma_common.cap_mask = pdata->cap_mask;
> + atdma->all_chan_mask = (1 << pdata->nr_channels) - 1;
> +
> + size = io->end - io->start + 1;
> + if (!request_mem_region(io->start, size, pdev->dev.driver->name)) {
> + err = -EBUSY;
> + goto err_kfree;
> + }
> +
> + atdma->regs = ioremap(io->start, size);
> + if (!atdma->regs) {
> + err = -ENOMEM;
> + goto err_release_r;
> + }
> +
> + atdma->clk = clk_get(&pdev->dev, "dma_clk");
> + if (IS_ERR(atdma->clk)) {
> + err = PTR_ERR(atdma->clk);
> + goto err_clk;
> + }
> + clk_enable(atdma->clk);
> +
> + /* force dma off, just in case */
> + at_dma_off(atdma);
> +
> + err = request_irq(irq, at_dma_interrupt, 0, "at_hdmac", atdma);
> + if (err)
> + goto err_irq;
> +
> + platform_set_drvdata(pdev, atdma);
> +
> + /* creates a pool of consistent memory blocks for hardware descriptors */
> + atdma->dma_desc_pool = dma_pool_create("at_hdmac_desc_pool",
> + &pdev->dev, sizeof(struct at_desc),
> + 4 /* word alignment */, 0);
> + if (!atdma->dma_desc_pool) {
> + dev_err(&pdev->dev, "No memory for descriptors dma pool\n");
> + err = -ENOMEM;
> + goto err_pool_create;
> + }
> +
> + /* initialize channels related values */
> + INIT_LIST_HEAD(&atdma->dma_common.channels);
> + for (i = 0; i < pdata->nr_channels; i++, atdma->dma_common.chancnt++) {
> + struct at_dma_chan *atchan = &atdma->chan[i];
> +
> + atchan->chan_common.device = &atdma->dma_common;
> + atchan->chan_common.cookie = atchan->completed_cookie = 1;
> + atchan->chan_common.chan_id = i;
> + list_add_tail(&atchan->chan_common.device_node, &atdma->dma_common.channels);
> +
> + atchan->ch_regs = atdma->regs + ch_regs(i);
> + spin_lock_init(&atchan->lock);
> + atchan->mask = 1 << i;
> +
> + INIT_LIST_HEAD(&atchan->active_list);
> + INIT_LIST_HEAD(&atchan->queue);
> + INIT_LIST_HEAD(&atchan->free_list);
> + }
> +
> + /* set base routines */
> + atdma->dma_common.device_alloc_chan_resources = atc_alloc_chan_resources;
> + atdma->dma_common.device_free_chan_resources = atc_free_chan_resources;
> + atdma->dma_common.device_is_tx_complete = atc_is_tx_complete;
> + atdma->dma_common.device_issue_pending = atc_issue_pending;
> + atdma->dma_common.dev = &pdev->dev;
> +
> + /* set prep routines based on capability */
> + if (dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask))
> + atdma->dma_common.device_prep_dma_memcpy = atc_prep_dma_memcpy;
> +
> + dma_writel(atdma, EN, AT_DMA_ENABLE);
> +
> + dev_info(&pdev->dev, "Atmel AHB DMA Controller ( %s%s), %d channels\n",
> + dma_has_cap(DMA_MEMCPY, atdma->dma_common.cap_mask) ? "cpy " : "",
> + dma_has_cap(DMA_SLAVE, atdma->dma_common.cap_mask) ? "slave " : "",
> + atdma->dma_common.chancnt);
> +
> + dma_async_device_register(&atdma->dma_common);
> +
> + return 0;
> +
> +err_pool_create:
> + platform_set_drvdata(pdev, NULL);
> + free_irq(platform_get_irq(pdev, 0), atdma);
> +err_irq:
> + clk_disable(atdma->clk);
> + clk_put(atdma->clk);
> +err_clk:
> + iounmap(atdma->regs);
> + atdma->regs = NULL;
> +err_release_r:
> + release_mem_region(io->start, size);
> +err_kfree:
> + kfree(atdma);
> + return err;
> +}
> +
> +static int __exit at_dma_remove(struct platform_device *pdev)
> +{
> + struct at_dma *atdma = platform_get_drvdata(pdev);
> + struct dma_chan *chan, *_chan;
> + struct resource *io;
> +
> + at_dma_off(atdma);
> + dma_async_device_unregister(&atdma->dma_common);
> +
> + dma_pool_destroy(atdma->dma_desc_pool);
> + platform_set_drvdata(pdev, NULL);
> + free_irq(platform_get_irq(pdev, 0), atdma);
> +
> + list_for_each_entry_safe(chan, _chan, &atdma->dma_common.channels,
> + device_node) {
> + tasklet_kill(&(to_at_dma_chan(chan)->tasklet));
> + list_del(&chan->device_node);
> + }
> +
> + clk_disable(atdma->clk);
> + clk_put(atdma->clk);
> +
> + iounmap(atdma->regs);
> + atdma->regs = NULL;
> +
> + io = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + release_mem_region(io->start, io->end - io->start + 1);
> +
> + kfree(atdma);
> +
> + return 0;
> +}
> +
> +static void at_dma_shutdown(struct platform_device *pdev)
> +{
> + struct at_dma *atdma = platform_get_drvdata(pdev);
> +
> + at_dma_off(platform_get_drvdata(pdev));
> + clk_disable(atdma->clk);
> +}
> +
> +static int at_dma_suspend_late(struct platform_device *pdev, pm_message_t mesg)
> +{
> + struct at_dma *atdma = platform_get_drvdata(pdev);
> +
> + at_dma_off(platform_get_drvdata(pdev));
> + clk_disable(atdma->clk);
> + return 0;
> +}
> +
> +static int at_dma_resume_early(struct platform_device *pdev)
> +{
> + struct at_dma *atdma = platform_get_drvdata(pdev);
> +
> + clk_enable(atdma->clk);
> + dma_writel(atdma, EN, AT_DMA_ENABLE);
> + return 0;
> +
> +}
> +
> +static struct platform_driver at_dma_driver = {
> + .remove = __exit_p(at_dma_remove),
> + .shutdown = at_dma_shutdown,
> + .suspend_late = at_dma_suspend_late,
> + .resume_early = at_dma_resume_early,
> + .driver = {
> + .name = "at_hdmac",
> + },
> +};
> +
> +static int __init at_dma_init(void)
> +{
> + return platform_driver_probe(&at_dma_driver, at_dma_probe);
> +}
> +module_init(at_dma_init);
> +
> +static void __exit at_dma_exit(void)
> +{
> + platform_driver_unregister(&at_dma_driver);
> +}
> +module_exit(at_dma_exit);
> +
> +MODULE_DESCRIPTION("Atmel AHB DMA Controller driver");
> +MODULE_AUTHOR("Nicolas Ferre <nicolas.ferre@atmel.com>");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:at_hdmac");
> diff --git a/drivers/dma/at_hdmac_regs.h b/drivers/dma/at_hdmac_regs.h
> new file mode 100644
> index 0000000..294f625
> --- /dev/null
> +++ b/drivers/dma/at_hdmac_regs.h
> @@ -0,0 +1,377 @@
> +/*
> + * Header file for the Atmel AHB DMA Controller driver
> + *
> + * Copyright (C) 2008 Atmel Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +#ifndef AT_HDMAC_REGS_H
> +#define AT_HDMAC_REGS_H
> +
> +#include <linux/at_hdmac.h>
> +
> +#define AT_DMA_MAX_NR_CHANNELS 8
> +
> +
> +#define AT_DMA_GCFG 0x00 /* Global Configuration Register */
> +#define AT_DMA_IF_BIGEND(i) (0x1 << (i)) /* AHB-Lite Interface i in Big-endian mode */
> +#define AT_DMA_ARB_CFG (0x1 << 4) /* Arbiter mode. */
> +#define AT_DMA_ARB_CFG_FIXED (0x0 << 4)
> +#define AT_DMA_ARB_CFG_ROUND_ROBIN (0x1 << 4)
> +
> +#define AT_DMA_EN 0x04 /* Controller Enable Register */
> +#define AT_DMA_ENABLE (0x1 << 0)
> +
> +#define AT_DMA_SREQ 0x08 /* Software Single Request Register */
> +#define AT_DMA_SSREQ(x) (0x1 << ((x) << 1)) /* Request a source single transfer on channel x */
> +#define AT_DMA_DSREQ(x) (0x1 << (1 + ((x) << 1))) /* Request a destination single transfer on channel x */
> +
> +#define AT_DMA_CREQ 0x0C /* Software Chunk Transfer Request Register */
> +#define AT_DMA_SCREQ(x) (0x1 << ((x) << 1)) /* Request a source chunk transfer on channel x */
> +#define AT_DMA_DCREQ(x) (0x1 << (1 + ((x) << 1))) /* Request a destination chunk transfer on channel x */
> +
> +#define AT_DMA_LAST 0x10 /* Software Last Transfer Flag Register */
> +#define AT_DMA_SLAST(x) (0x1 << ((x) << 1)) /* This src rq is last tx of buffer on channel x */
> +#define AT_DMA_DLAST(x) (0x1 << (1 + ((x) << 1))) /* This dst rq is last tx of buffer on channel x */
> +
> +#define AT_DMA_SYNC 0x14 /* Request Synchronization Register */
> +#define AT_DMA_SYR(h) (0x1 << (h)) /* Synchronize handshake line h */
> +
> +/* Error, Chained Buffer transfer completed and Buffer transfer completed Interrupt registers */
> +#define AT_DMA_EBCIER 0x18 /* Enable register */
> +#define AT_DMA_EBCIDR 0x1C /* Disable register */
> +#define AT_DMA_EBCIMR 0x20 /* Mask Register */
> +#define AT_DMA_EBCISR 0x24 /* Status Register */
> +#define AT_DMA_CBTC_OFFSET 8
> +#define AT_DMA_ERR_OFFSET 16
> +#define AT_DMA_BTC(x) (0x1 << (x))
> +#define AT_DMA_CBTC(x) (0x1 << (AT_DMA_CBTC_OFFSET + (x)))
> +#define AT_DMA_ERR(x) (0x1 << (AT_DMA_ERR_OFFSET + (x)))
> +
> +#define AT_DMA_CHER 0x28 /* Channel Handler Enable Register */
> +#define AT_DMA_ENA(x) (0x1 << (x))
> +#define AT_DMA_SUSP(x) (0x1 << ( 8 + (x)))
> +#define AT_DMA_KEEP(x) (0x1 << (24 + (x)))
> +
> +#define AT_DMA_CHDR 0x2C /* Channel Handler Disable Register */
> +#define AT_DMA_DIS(x) (0x1 << (x))
> +#define AT_DMA_RES(x) (0x1 << ( 8 + (x)))
> +
> +#define AT_DMA_CHSR 0x30 /* Channel Handler Status Register */
> +#define AT_DMA_EMPT(x) (0x1 << (16 + (x)))
> +#define AT_DMA_STAL(x) (0x1 << (24 + (x)))
> +
> +
> +#define AT_DMA_CH_REGS_BASE 0x3C /* Channel registers base address */
> +#define ch_regs(x) (AT_DMA_CH_REGS_BASE + (x) * 0x28) /* Channel x base addr */
> +
> +/* Hardware register offset for each channel */
> +#define ATC_SADDR_OFFSET 0x00 /* Source Address Register */
> +#define ATC_DADDR_OFFSET 0x04 /* Destination Address Register */
> +#define ATC_DSCR_OFFSET 0x08 /* Descriptor Address Register */
> +#define ATC_CTRLA_OFFSET 0x0C /* Control A Register */
> +#define ATC_CTRLB_OFFSET 0x10 /* Control B Register */
> +#define ATC_CFG_OFFSET 0x14 /* Configuration Register */
> +#define ATC_SPIP_OFFSET 0x18 /* Src PIP Configuration Register */
> +#define ATC_DPIP_OFFSET 0x1C /* Dst PIP Configuration Register */
> +
> +
> +/* Bitfield definitions */
> +
> +/* Bitfields in DSCR */
> +#define ATC_DSCR_IF(i) (0x3 & (i)) /* Dsc feched via AHB-Lite Interface i */
> +
> +/* Bitfields in CTRLA */
> +#define ATC_BTSIZE_MAX 0xFFFFUL /* Maximum Buffer Transfer Size */
> +#define ATC_BTSIZE(x) (ATC_BTSIZE_MAX & (x)) /* Buffer Transfer Size */
> +#define ATC_SCSIZE_MASK (0x7 << 16) /* Source Chunk Transfer Size */
> +#define ATC_SCSIZE_1 (0x0 << 16)
> +#define ATC_SCSIZE_4 (0x1 << 16)
> +#define ATC_SCSIZE_8 (0x2 << 16)
> +#define ATC_SCSIZE_16 (0x3 << 16)
> +#define ATC_SCSIZE_32 (0x4 << 16)
> +#define ATC_SCSIZE_64 (0x5 << 16)
> +#define ATC_SCSIZE_128 (0x6 << 16)
> +#define ATC_SCSIZE_256 (0x7 << 16)
> +#define ATC_DCSIZE_MASK (0x7 << 20) /* Destination Chunk Transfer Size */
> +#define ATC_DCSIZE_1 (0x0 << 20)
> +#define ATC_DCSIZE_4 (0x1 << 20)
> +#define ATC_DCSIZE_8 (0x2 << 20)
> +#define ATC_DCSIZE_16 (0x3 << 20)
> +#define ATC_DCSIZE_32 (0x4 << 20)
> +#define ATC_DCSIZE_64 (0x5 << 20)
> +#define ATC_DCSIZE_128 (0x6 << 20)
> +#define ATC_DCSIZE_256 (0x7 << 20)
> +#define ATC_SRC_WIDTH_MASK (0x3 << 24) /* Source Single Transfer Size */
> +#define ATC_SRC_WIDTH_BYTE (0x0 << 24)
> +#define ATC_SRC_WIDTH_HALFWORD (0x1 << 24)
> +#define ATC_SRC_WIDTH_WORD (0x2 << 24)
> +#define ATC_DST_WIDTH_MASK (0x3 << 28) /* Destination Single Transfer Size */
> +#define ATC_DST_WIDTH_BYTE (0x0 << 28)
> +#define ATC_DST_WIDTH_HALFWORD (0x1 << 28)
> +#define ATC_DST_WIDTH_WORD (0x2 << 28)
> +#define ATC_DONE (0x1 << 31) /* Tx Done (only written back in descriptor) */
> +
> +/* Bitfields in CTRLB */
> +#define ATC_SIF(i) (0x3 & (i)) /* Src tx done via AHB-Lite Interface i */
> +#define ATC_DIF(i) ((0x3 & (i)) << 4) /* Dst tx done via AHB-Lite Interface i */
> +#define ATC_SRC_PIP (0x1 << 8) /* Source Picture-in-Picture enabled */
> +#define ATC_DST_PIP (0x1 << 12) /* Destination Picture-in-Picture enabled */
> +#define ATC_SRC_DSCR_DIS (0x1 << 16) /* Src Descriptor fetch disable */
> +#define ATC_DST_DSCR_DIS (0x1 << 20) /* Dst Descriptor fetch disable */
> +#define ATC_FC_MASK (0x7 << 21) /* Choose Flow Controller */
> +#define ATC_FC_MEM2MEM (0x0 << 21) /* Mem-to-Mem (DMA) */
> +#define ATC_FC_MEM2PER (0x1 << 21) /* Mem-to-Periph (DMA) */
> +#define ATC_FC_PER2MEM (0x2 << 21) /* Periph-to-Mem (DMA) */
> +#define ATC_FC_PER2PER (0x3 << 21) /* Periph-to-Periph (DMA) */
> +#define ATC_FC_PER2MEM_PER (0x4 << 21) /* Periph-to-Mem (Peripheral) */
> +#define ATC_FC_MEM2PER_PER (0x5 << 21) /* Mem-to-Periph (Peripheral) */
> +#define ATC_FC_PER2PER_PER (0x6 << 21) /* Periph-to-Periph (Src Peripheral) */
> +#define ATC_SRC_ADDR_MODE_MASK (0x3 << 24)
> +#define ATC_SRC_ADDR_MODE_INCR (0x0 << 24) /* Incrementing Mode */
> +#define ATC_SRC_ADDR_MODE_DECR (0x1 << 24) /* Decrementing Mode */
> +#define ATC_SRC_ADDR_MODE_FIXED (0x2 << 24) /* Fixed Mode */
> +#define ATC_DST_ADDR_MODE_MASK (0x3 << 28)
> +#define ATC_DST_ADDR_MODE_INCR (0x0 << 28) /* Incrementing Mode */
> +#define ATC_DST_ADDR_MODE_DECR (0x1 << 28) /* Decrementing Mode */
> +#define ATC_DST_ADDR_MODE_FIXED (0x2 << 28) /* Fixed Mode */
> +#define ATC_IEN (0x1 << 30) /* BTC interrupt enable (active low) */
> +#define ATC_AUTO (0x1 << 31) /* Auto multiple buffer tx enable */
> +
> +/* Bitfields in CFG */
> +#define ATC_SRC_PER(h) (0xFU & (h)) /* Channel src rq associated with periph handshaking ifc h */
> +#define ATC_DST_PER(h) ((0xFU & (h)) << 4) /* Channel dst rq associated with periph handshaking ifc h */
> +#define ATC_SRC_REP (0x1 << 8) /* Source Replay Mod */
> +#define ATC_SRC_H2SEL (0x1 << 9) /* Source Handshaking Mod */
> +#define ATC_SRC_H2SEL_SW (0x0 << 9)
> +#define ATC_SRC_H2SEL_HW (0x1 << 9)
> +#define ATC_DST_REP (0x1 << 12) /* Destination Replay Mod */
> +#define ATC_DST_H2SEL (0x1 << 13) /* Destination Handshaking Mod */
> +#define ATC_DST_H2SEL_SW (0x0 << 13)
> +#define ATC_DST_H2SEL_HW (0x1 << 13)
> +#define ATC_SOD (0x1 << 16) /* Stop On Done */
> +#define ATC_LOCK_IF (0x1 << 20) /* Interface Lock */
> +#define ATC_LOCK_B (0x1 << 21) /* AHB Bus Lock */
> +#define ATC_LOCK_IF_L (0x1 << 22) /* Master Interface Arbiter Lock */
> +#define ATC_LOCK_IF_L_CHUNK (0x0 << 22)
> +#define ATC_LOCK_IF_L_BUFFER (0x1 << 22)
> +#define ATC_AHB_PROT_MASK (0x7 << 24) /* AHB Protection */
> +#define ATC_FIFOCFG_MASK (0x3 << 28) /* FIFO Request Configuration */
> +#define ATC_FIFOCFG_LARGESTBURST (0x0 << 28)
> +#define ATC_FIFOCFG_HALFFIFO (0x1 << 28)
> +#define ATC_FIFOCFG_ENOUGHSPACE (0x2 << 28)
> +
> +/* Bitfields in SPIP */
> +#define ATC_SPIP_HOLE(x) (0xFFFFU & (x))
> +#define ATC_SPIP_BOUNDARY(x) ((0x3FF & (x)) << 16)
> +
> +/* Bitfields in DPIP */
> +#define ATC_DPIP_HOLE(x) (0xFFFFU & (x))
> +#define ATC_DPIP_BOUNDARY(x) ((0x3FF & (x)) << 16)
> +
> +
> +/*-- descriptors -----------------------------------------------------*/
> +
> +/* LLI == Linked List Item; aka DMA buffer descriptor */
> +struct at_lli {
> + /* values that are not changed by hardware */
> + dma_addr_t saddr;
> + dma_addr_t daddr;
> + /* value that may get written back: */
> + u32 ctrla;
> + /* more values that are not changed by hardware */
> + u32 ctrlb;
> + dma_addr_t dscr; /* chain to next lli */
> +};
> +
> +/**
> + * struct at_desc - software descriptor
> + * @at_lli: hardware lli structure
> + * @txd: support for the async_tx api
> + * @desc_node: node on the channed descriptors list
> + * @len: total transaction bytecount
> + */
> +struct at_desc {
> + /* FIRST values the hardware uses */
> + struct at_lli lli;
> +
> + /* THEN values for driver housekeeping */
> + struct dma_async_tx_descriptor txd;
> + struct list_head desc_node;
> + size_t len;
> +};
> +
> +static inline struct at_desc *
> +txd_to_at_desc(struct dma_async_tx_descriptor *txd)
> +{
> + return container_of(txd, struct at_desc, txd);
> +}
> +
> +
> +/*-- Channels --------------------------------------------------------*/
> +
> +/**
> + * struct at_dma_chan - internal representation of an Atmel HDMAC channel
> + * @chan_common: common dmaengine channel object members
> + * @device: parent device
> + * @ch_regs: memory mapped register base
> + * @mask: channel index in a mask
> + * @error_status: transmit error status information from irq handler
> + * to tasklet (use atomic operations)
> + * @tasklet: bottom half to finish transaction work
> + * @lock: serializes enqueue/dequeue operations to descriptors lists
> + * @completed_cookie: identifier for the most recently completed operation
> + * @active_list: list of descriptors dmaengine is being running on
> + * @queue: list of descriptors ready to be submitted to engine
> + * @free_list: list of descriptors usable by the channel
> + * @descs_allocated: records the actual size of the descriptor pool
> + */
> +struct at_dma_chan {
> + struct dma_chan chan_common;
> + struct at_dma *device;
> + void __iomem *ch_regs;
> + u8 mask;
> + unsigned long error_status;
> + struct tasklet_struct tasklet;
> +
> + spinlock_t lock;
> +
> + /* these other elements are all protected by lock */
> + dma_cookie_t completed_cookie;
> + struct list_head active_list;
> + struct list_head queue;
> + struct list_head free_list;
> + unsigned int descs_allocated;
> +};
> +
> +#define channel_readl(atchan, name) \
> + __raw_readl((atchan)->ch_regs + ATC_##name##_OFFSET)
> +
> +#define channel_writel(atchan, name, val) \
> + __raw_writel((val), (atchan)->ch_regs + ATC_##name##_OFFSET)
> +
> +static inline struct at_dma_chan *to_at_dma_chan(struct dma_chan *dchan)
> +{
> + return container_of(dchan, struct at_dma_chan, chan_common);
> +}
> +
> +
> +/*-- Controller ------------------------------------------------------*/
> +
> +/**
> + * struct at_dma - internal representation of an Atmel HDMA Controller
> + * @chan_common: common dmaengine dma_device object members
> + * @ch_regs: memory mapped register base
> + * @clk: dma controller clock
> + * @all_chan_mask: all channels availlable in a mask
> + * @dma_desc_pool: base of DMA descriptor region (DMA address)
> + * @chan: channels table to store at_dma_chan structures
> + */
> +struct at_dma {
> + struct dma_device dma_common;
> + void __iomem *regs;
> + struct clk *clk;
> +
> + u8 all_chan_mask;
> +
> + struct dma_pool *dma_desc_pool;
> + /* AT THE END channels table */
> + struct at_dma_chan chan[0];
> +};
> +
> +#define dma_readl(atdma, name) \
> + __raw_readl((atdma)->regs + AT_DMA_##name)
> +#define dma_writel(atdma, name, val) \
> + __raw_writel((val), (atdma)->regs + AT_DMA_##name)
> +
> +static inline struct at_dma *to_at_dma(struct dma_device *ddev)
> +{
> + return container_of(ddev, struct at_dma, dma_common);
> +}
> +
> +
> +/*-- Helper functions ------------------------------------------------*/
> +
> +#if defined(VERBOSE_DEBUG)
> +static void vdbg_dump_regs(struct at_dma_chan *atchan)
> +{
> + struct at_dma *atdma = to_at_dma(atchan->chan_common.device);
> +
> + dev_err(&atchan->chan_common.dev,
> + " channel %d : imr = 0x%x, chsr = 0x%x\n",
> + atchan->chan_common.chan_id,
> + dma_readl(atdma, EBCIMR),
> + dma_readl(atdma, CHSR));
> +
> + dev_err(&atchan->chan_common.dev,
> + " channel: s0x%x d0x%x ctrl0x%x:0x%x l0x%x\n",
> + channel_readl(atchan, SADDR),
> + channel_readl(atchan, DADDR),
> + channel_readl(atchan, CTRLA),
> + channel_readl(atchan, CTRLB),
> + channel_readl(atchan, DSCR));
> +}
> +#else
> +static void vdbg_dump_regs(struct at_dma_chan *atchan) {}
> +#endif
> +
> +static void atc_dump_lli(struct at_dma_chan *atchan, struct at_lli *lli)
> +{
> + dev_printk(KERN_CRIT, &atchan->chan_common.dev,
> + " desc: s0x%x d0x%x ctrl0x%x:0x%x l0x%x\n",
> + lli->saddr, lli->daddr,
> + lli->ctrla, lli->ctrlb, lli->dscr);
> +}
> +
> +
> +static void atc_setup_irq(struct at_dma_chan *atchan, int on)
> +{
> + struct at_dma *atdma = to_at_dma(atchan->chan_common.device);
> + u32 ebci;
> +
> + /* enable interrupts on buffer chain completion & error */
> + ebci = AT_DMA_CBTC(atchan->chan_common.chan_id)
> + | AT_DMA_ERR(atchan->chan_common.chan_id);
> + if (on)
> + dma_writel(atdma, EBCIER, ebci);
> + else
> + dma_writel(atdma, EBCIDR, ebci);
> +}
> +
> +static inline void atc_enable_irq(struct at_dma_chan *atchan)
> +{
> + atc_setup_irq(atchan, 1);
> +}
> +
> +static inline void atc_disable_irq(struct at_dma_chan *atchan)
> +{
> + atc_setup_irq(atchan, 0);
> +}
> +
> +
> +/**
> + * atc_chan_is_enabled - test if given channel is enabled
> + * @atchan: channel we want to test status
> + */
> +static inline int atc_chan_is_enabled(struct at_dma_chan *atchan)
> +{
> + struct at_dma *atdma = to_at_dma(atchan->chan_common.device);
> +
> + return !!(dma_readl(atdma, CHSR) & atchan->mask);
> +}
> +
> +
> +/**
> + * set_desc_eol - set end-of-link to descriptor so it will end transfer
> + * @desc: descriptor, signle or at the end of a chain, to end chain on
> + */
> +static void set_desc_eol(struct at_desc *desc)
> +{
> + desc->lli.ctrlb |= ATC_SRC_DSCR_DIS | ATC_DST_DSCR_DIS;
> + desc->lli.dscr = 0;
> +}
> +
> +#endif /* AT_HDMAC_REGS_H */
> diff --git a/include/linux/at_hdmac.h b/include/linux/at_hdmac.h
> new file mode 100644
> index 0000000..21a5554
> --- /dev/null
> +++ b/include/linux/at_hdmac.h
> @@ -0,0 +1,26 @@
> +/*
> + * Header file for the Atmel AHB DMA Controller driver
> + *
> + * Copyright (C) 2008 Atmel Corporation
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +#ifndef AT_HDMAC_H
> +#define AT_HDMAC_H
> +
> +#include <linux/dmaengine.h>
> +
> +/**
> + * struct at_dma_platform_data - Controller configuration parameters
> + * @nr_channels: Number of channels supported by hardware (max 8)
> + * @cap_mask: dma_capability flags supported by the platform
> + */
> +struct at_dma_platform_data {
> + unsigned int nr_channels;
> + dma_cap_mask_t cap_mask;
> +};
> +
> +#endif /* AT_HDMAC_H */
> --
> 1.5.3.7
>
>
>
>
>



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