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Subject[PATCH] ata: pata_pxa: dmaengine conversion
Date
The PXA architecture was offered a slave dmaengine support. As a
consequence the direct DMA registers are progressively replaced by
dmaengine support.

This makes the pata_pxa change, which brings this driver to almost a
generic ATA 40-wires driver relying on dmaengine for transfers.

Signed-off-by: Robert Jarzmik <robert.jarzmik@free.fr>
---
drivers/ata/pata_pxa.c | 171 +++++++++++++++++--------------------------------
1 file changed, 59 insertions(+), 112 deletions(-)

diff --git a/drivers/ata/pata_pxa.c b/drivers/ata/pata_pxa.c
index c36b3e6531d8..f6c46e9a4dc0 100644
--- a/drivers/ata/pata_pxa.c
+++ b/drivers/ata/pata_pxa.c
@@ -24,79 +24,36 @@
#include <linux/ata.h>
#include <linux/libata.h>
#include <linux/platform_device.h>
+#include <linux/dmaengine.h>
+#include <linux/dma/pxa-dma.h>
#include <linux/gpio.h>
#include <linux/slab.h>
#include <linux/completion.h>

#include <scsi/scsi_host.h>

-#include <mach/pxa2xx-regs.h>
#include <linux/platform_data/ata-pxa.h>
-#include <mach/dma.h>

#define DRV_NAME "pata_pxa"
#define DRV_VERSION "0.1"

struct pata_pxa_data {
- uint32_t dma_channel;
- struct pxa_dma_desc *dma_desc;
- dma_addr_t dma_desc_addr;
- uint32_t dma_desc_id;
-
- /* DMA IO physical address */
- uint32_t dma_io_addr;
- /* PXA DREQ<0:2> pin selector */
- uint32_t dma_dreq;
- /* DMA DCSR register value */
- uint32_t dma_dcsr;
-
+ struct dma_chan *dma_chan;
+ dma_cookie_t dma_cookie;
struct completion dma_done;
};

/*
- * Setup the DMA descriptors. The size is transfer capped at 4k per descriptor,
- * if the transfer is longer, it is split into multiple chained descriptors.
+ * DMA interrupt handler.
*/
-static void pxa_load_dmac(struct scatterlist *sg, struct ata_queued_cmd *qc)
+static void pxa_ata_dma_irq(void *d)
{
- struct pata_pxa_data *pd = qc->ap->private_data;
-
- uint32_t cpu_len, seg_len;
- dma_addr_t cpu_addr;
-
- cpu_addr = sg_dma_address(sg);
- cpu_len = sg_dma_len(sg);
-
- do {
- seg_len = (cpu_len > 0x1000) ? 0x1000 : cpu_len;
-
- pd->dma_desc[pd->dma_desc_id].ddadr = pd->dma_desc_addr +
- ((pd->dma_desc_id + 1) * sizeof(struct pxa_dma_desc));
-
- pd->dma_desc[pd->dma_desc_id].dcmd = DCMD_BURST32 |
- DCMD_WIDTH2 | (DCMD_LENGTH & seg_len);
-
- if (qc->tf.flags & ATA_TFLAG_WRITE) {
- pd->dma_desc[pd->dma_desc_id].dsadr = cpu_addr;
- pd->dma_desc[pd->dma_desc_id].dtadr = pd->dma_io_addr;
- pd->dma_desc[pd->dma_desc_id].dcmd |= DCMD_INCSRCADDR |
- DCMD_FLOWTRG;
- } else {
- pd->dma_desc[pd->dma_desc_id].dsadr = pd->dma_io_addr;
- pd->dma_desc[pd->dma_desc_id].dtadr = cpu_addr;
- pd->dma_desc[pd->dma_desc_id].dcmd |= DCMD_INCTRGADDR |
- DCMD_FLOWSRC;
- }
-
- cpu_len -= seg_len;
- cpu_addr += seg_len;
- pd->dma_desc_id++;
+ struct pata_pxa_data *pd = d;
+ enum dma_status status;

- } while (cpu_len);
-
- /* Should not happen */
- if (seg_len & 0x1f)
- DALGN |= (1 << pd->dma_dreq);
+ status = dmaengine_tx_status(pd->dma_chan, pd->dma_cookie, NULL);
+ if (status == DMA_ERROR || status == DMA_COMPLETE)
+ complete(&pd->dma_done);
}

/*
@@ -105,28 +62,22 @@ static void pxa_load_dmac(struct scatterlist *sg, struct ata_queued_cmd *qc)
static void pxa_qc_prep(struct ata_queued_cmd *qc)
{
struct pata_pxa_data *pd = qc->ap->private_data;
- int si = 0;
- struct scatterlist *sg;
+ struct dma_async_tx_descriptor *tx;
+ enum dma_transfer_direction dir;

if (!(qc->flags & ATA_QCFLAG_DMAMAP))
return;

- pd->dma_desc_id = 0;
-
- DCSR(pd->dma_channel) = 0;
- DALGN &= ~(1 << pd->dma_dreq);
-
- for_each_sg(qc->sg, sg, qc->n_elem, si)
- pxa_load_dmac(sg, qc);
-
- pd->dma_desc[pd->dma_desc_id - 1].ddadr = DDADR_STOP;
-
- /* Fire IRQ only at the end of last block */
- pd->dma_desc[pd->dma_desc_id - 1].dcmd |= DCMD_ENDIRQEN;
-
- DDADR(pd->dma_channel) = pd->dma_desc_addr;
- DRCMR(pd->dma_dreq) = DRCMR_MAPVLD | pd->dma_channel;
-
+ dir = (qc->dma_dir == DMA_TO_DEVICE ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM);
+ tx = dmaengine_prep_slave_sg(pd->dma_chan, qc->sg, qc->n_elem, dir,
+ DMA_PREP_INTERRUPT);
+ if (!tx) {
+ ata_dev_err(qc->dev, "prep_slave_sg() failed\n");
+ return;
+ }
+ tx->callback = pxa_ata_dma_irq;
+ tx->callback_param = pd;
+ pd->dma_cookie = dmaengine_submit(tx);
}

/*
@@ -145,7 +96,7 @@ static void pxa_bmdma_start(struct ata_queued_cmd *qc)
{
struct pata_pxa_data *pd = qc->ap->private_data;
init_completion(&pd->dma_done);
- DCSR(pd->dma_channel) = DCSR_RUN;
+ dma_async_issue_pending(pd->dma_chan);
}

/*
@@ -154,12 +105,14 @@ static void pxa_bmdma_start(struct ata_queued_cmd *qc)
static void pxa_bmdma_stop(struct ata_queued_cmd *qc)
{
struct pata_pxa_data *pd = qc->ap->private_data;
+ enum dma_status status;

- if ((DCSR(pd->dma_channel) & DCSR_RUN) &&
- wait_for_completion_timeout(&pd->dma_done, HZ))
- dev_err(qc->ap->dev, "Timeout waiting for DMA completion!");
+ status = dmaengine_tx_status(pd->dma_chan, pd->dma_cookie, NULL);
+ if (status != DMA_ERROR && status != DMA_COMPLETE &&
+ wait_for_completion_timeout(&pd->dma_done, HZ))
+ ata_dev_err(qc->dev, "Timeout waiting for DMA completion!");

- DCSR(pd->dma_channel) = 0;
+ dmaengine_terminate_all(pd->dma_chan);
}

/*
@@ -170,8 +123,11 @@ static unsigned char pxa_bmdma_status(struct ata_port *ap)
{
struct pata_pxa_data *pd = ap->private_data;
unsigned char ret = ATA_DMA_INTR;
+ struct dma_tx_state state;
+ enum dma_status status;

- if (pd->dma_dcsr & DCSR_BUSERR)
+ status = dmaengine_tx_status(pd->dma_chan, pd->dma_cookie, &state);
+ if (status != DMA_COMPLETE)
ret |= ATA_DMA_ERR;

return ret;
@@ -213,21 +169,6 @@ static struct ata_port_operations pxa_ata_port_ops = {
.qc_prep = pxa_qc_prep,
};

-/*
- * DMA interrupt handler.
- */
-static void pxa_ata_dma_irq(int dma, void *port)
-{
- struct ata_port *ap = port;
- struct pata_pxa_data *pd = ap->private_data;
-
- pd->dma_dcsr = DCSR(dma);
- DCSR(dma) = pd->dma_dcsr;
-
- if (pd->dma_dcsr & DCSR_STOPSTATE)
- complete(&pd->dma_done);
-}
-
static int pxa_ata_probe(struct platform_device *pdev)
{
struct ata_host *host;
@@ -238,6 +179,9 @@ static int pxa_ata_probe(struct platform_device *pdev)
struct resource *dma_res;
struct resource *irq_res;
struct pata_pxa_pdata *pdata = dev_get_platdata(&pdev->dev);
+ struct dma_slave_config config;
+ dma_cap_mask_t mask;
+ struct pxad_param param;
int ret = 0;

/*
@@ -333,29 +277,32 @@ static int pxa_ata_probe(struct platform_device *pdev)
return -ENOMEM;

ap->private_data = data;
- data->dma_dreq = pdata->dma_dreq;
- data->dma_io_addr = dma_res->start;

- /*
- * Allocate space for the DMA descriptors
- */
- data->dma_desc = dmam_alloc_coherent(&pdev->dev, PAGE_SIZE,
- &data->dma_desc_addr, GFP_KERNEL);
- if (!data->dma_desc)
- return -EINVAL;
+ dma_cap_zero(mask);
+ dma_cap_set(DMA_SLAVE, mask);
+ param.prio = PXAD_PRIO_LOWEST;
+ param.drcmr = pdata->dma_dreq;
+ memset(&config, 0, sizeof(config));
+ config.src_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+ config.dst_addr_width = DMA_SLAVE_BUSWIDTH_2_BYTES;
+ config.src_addr = dma_res->start;
+ config.dst_addr = dma_res->start;
+ config.src_maxburst = 32;
+ config.dst_maxburst = 32;

/*
* Request the DMA channel
*/
- data->dma_channel = pxa_request_dma(DRV_NAME, DMA_PRIO_LOW,
- pxa_ata_dma_irq, ap);
- if (data->dma_channel < 0)
+ data->dma_chan =
+ dma_request_slave_channel_compat(mask, pxad_filter_fn,
+ &param, &pdev->dev, "data");
+ if (!data->dma_chan)
return -EBUSY;
-
- /*
- * Stop and clear the DMA channel
- */
- DCSR(data->dma_channel) = 0;
+ ret = dmaengine_slave_config(data->dma_chan, &config);
+ if (ret < 0) {
+ dev_err(&pdev->dev, "dma configuration failed: %d\n", ret);
+ return ret;
+ }

/*
* Activate the ATA host
@@ -363,7 +310,7 @@ static int pxa_ata_probe(struct platform_device *pdev)
ret = ata_host_activate(host, irq_res->start, ata_sff_interrupt,
pdata->irq_flags, &pxa_ata_sht);
if (ret)
- pxa_free_dma(data->dma_channel);
+ dma_release_channel(data->dma_chan);

return ret;
}
@@ -373,7 +320,7 @@ static int pxa_ata_remove(struct platform_device *pdev)
struct ata_host *host = platform_get_drvdata(pdev);
struct pata_pxa_data *data = host->ports[0]->private_data;

- pxa_free_dma(data->dma_channel);
+ dma_release_channel(data->dma_chan);

ata_host_detach(host);

--
2.1.4


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