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SubjectRe: [PATCH 05/12] dmaengine: Add STM32 DMA3 support
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On 5/16/24 19:09, Frank Li wrote:
> On Thu, May 16, 2024 at 05:25:58PM +0200, Amelie Delaunay wrote:
>> On 5/15/24 20:56, Frank Li wrote:
>>> On Tue, Apr 23, 2024 at 02:32:55PM +0200, Amelie Delaunay wrote:
>>>> STM32 DMA3 driver supports the 3 hardware configurations of the STM32 DMA3
>>>> controller:
> ...
>>>> + writel_relaxed(hwdesc->cdar, ddata->base + STM32_DMA3_CDAR(id));
>>>> + writel_relaxed(hwdesc->cllr, ddata->base + STM32_DMA3_CLLR(id));
>>>> +
>>>> + /* Clear any pending interrupts */
>>>> + csr = readl_relaxed(ddata->base + STM32_DMA3_CSR(id));
>>>> + if (csr & CSR_ALL_F)
>>>> + writel_relaxed(csr, ddata->base + STM32_DMA3_CFCR(id));
>>>> +
>>>> + stm32_dma3_chan_dump_reg(chan);
>>>> +
>>>> + ccr = readl_relaxed(ddata->base + STM32_DMA3_CCR(id));
>>>> + writel_relaxed(ccr | CCR_EN, ddata->base + STM32_DMA3_CCR(id));
>>>
>>> This one should use writel instead of writel_relaxed because it need
>>> dma_wmb() as barrier for preious write complete.
>>>
>>> Frank
>>>
>>
>> ddata->base is Device memory type thanks to ioremap() use, so it is strongly
>> ordered and non-cacheable.
>> DMA3 is outside CPU cluster, its registers are accessible through AHB bus.
>> dma_wmb() (in case of writel instead of writel_relaxed) is useless in that
>> case: it won't ensure the propagation on the bus is complete, and it will
>> have impacts on the system.
>> That's why CCR register is written once, then it is read before CCR_EN is
>> set and being written again, with _relaxed(), because registers are behind a
>> bus, and ioremapped with Device memory type which ensures it is strongly
>> ordered and non-cacheable.
>
> regardless memory map, writel_relaxed() just make sure io write and read is
> orderred, not necessary order with other memory access. only readl and
> writel make sure order with other memory read/write.
>
> 1. Write src_addr to descriptor
> 2. dma_wmb()
> 3. Write "ready" to descriptor
> 4. enable channel or doorbell by write a register.
>
> if 4 use writel_relaxe(). because 3 write to DDR, which difference place of
> mmio, 4 may happen before 3. Your can refer axi order model.
>
> 4 have to use ONE writel(), to make sure 3 already write to DDR.
>
> You need use at least one writel() to make sure all nornmal memory finish.
>

+ writel_relaxed(chan->swdesc->ccr, ddata->base + STM32_DMA3_CCR(id));
+ writel_relaxed(hwdesc->ctr1, ddata->base + STM32_DMA3_CTR1(id));
+ writel_relaxed(hwdesc->ctr2, ddata->base + STM32_DMA3_CTR2(id));
+ writel_relaxed(hwdesc->cbr1, ddata->base + STM32_DMA3_CBR1(id));
+ writel_relaxed(hwdesc->csar, ddata->base + STM32_DMA3_CSAR(id));
+ writel_relaxed(hwdesc->cdar, ddata->base + STM32_DMA3_CDAR(id));
+ writel_relaxed(hwdesc->cllr, ddata->base + STM32_DMA3_CLLR(id));

These writel_relaxed() are from descriptors to DMA3 registers
(descriptors being prepared "a long time ago" during _prep_).
As I said previously, DMA3 registers are outside CPU cluster, accessible
through AHB bus, and ddata->base to address registers is ioremapped as
Device memory type, non-cacheable and strongly ordered.

arch/arm/include/asm/io.h:
/*
* ioremap() and friends.
*
* ioremap() takes a resource address, and size. Due to the ARM memory
* types, it is important to use the correct ioremap() function as each
* mapping has specific properties.
*
* Function Memory type Cacheability Cache hint
* *ioremap()* *Device* *n/a* *n/a*
* ioremap_cache() Normal Writeback Read allocate
* ioremap_wc() Normal Non-cacheable n/a
* ioremap_wt() Normal Non-cacheable n/a
*
* All device mappings have the following properties:
* - no access speculation
* - no repetition (eg, on return from an exception)
* - number, order and size of accesses are maintained
* - unaligned accesses are "unpredictable"
* - writes may be delayed before they hit the endpoint device

On our platforms, we know that to ensure the writes have hit the
endpoint device (aka DMA3 registers), a read have to be done before.
And that's what is done before enabling the channel:

+ ccr = readl_relaxed(ddata->base + STM32_DMA3_CCR(id));
+ writel_relaxed(ccr | CCR_EN, ddata->base + STM32_DMA3_CCR(id));

If there was an issue in this part of the code, it means channel would
be started while it is wrongly programmed. In that case, DMA3 would
raise a User Setting Error interrupt and disable the channel. User
Setting Error is managed in this driver
(USEF/stm32_dma3_check_user_setting()). And we never had reached a
situation.

>>
>>>> +
>>>> + chan->dma_status = DMA_IN_PROGRESS;
>>>> +
>>>> + dev_dbg(chan2dev(chan), "vchan %pK: started\n", &chan->vchan);
>>>> +}
>>>> +
>>>> +static int stm32_dma3_chan_suspend(struct stm32_dma3_chan *chan, bool susp)
>>>> +{
>>>> + struct stm32_dma3_ddata *ddata = to_stm32_dma3_ddata(chan);
>>>> + u32 csr, ccr = readl_relaxed(ddata->base + STM32_DMA3_CCR(chan->id)) & ~CCR_EN;
>>>> + int ret = 0;
>>>> +
>>>> + if (susp)
>>>> + ccr |= CCR_SUSP;
>>>> + else
>>>> + ccr &= ~CCR_SUSP;
>>>> +
>>>> + writel_relaxed(ccr, ddata->base + STM32_DMA3_CCR(chan->id));
>>>> +
>>>> + if (susp) {
>>>> + ret = readl_relaxed_poll_timeout_atomic(ddata->base + STM32_DMA3_CSR(chan->id), csr,
>>>> + csr & CSR_SUSPF, 1, 10);
>>>> + if (!ret)
>>>> + writel_relaxed(CFCR_SUSPF, ddata->base + STM32_DMA3_CFCR(chan->id));
>>>> +
>>>> + stm32_dma3_chan_dump_reg(chan);
>>>> + }
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +static void stm32_dma3_chan_reset(struct stm32_dma3_chan *chan)
>>>> +{
>>>> + struct stm32_dma3_ddata *ddata = to_stm32_dma3_ddata(chan);
>>>> + u32 ccr = readl_relaxed(ddata->base + STM32_DMA3_CCR(chan->id)) & ~CCR_EN;
>>>> +
>>>> + writel_relaxed(ccr |= CCR_RESET, ddata->base + STM32_DMA3_CCR(chan->id));
>>>> +}
>>>> +
>>>> +static int stm32_dma3_chan_stop(struct stm32_dma3_chan *chan)
>>>> +{
>>>> + struct stm32_dma3_ddata *ddata = to_stm32_dma3_ddata(chan);
>>>> + u32 ccr;
>>>> + int ret = 0;
>>>> +
>>>> + chan->dma_status = DMA_COMPLETE;
>>>> +
>>>> + /* Disable interrupts */
>>>> + ccr = readl_relaxed(ddata->base + STM32_DMA3_CCR(chan->id));
>>>> + writel_relaxed(ccr & ~(CCR_ALLIE | CCR_EN), ddata->base + STM32_DMA3_CCR(chan->id));
>>>> +
>>>> + if (!(ccr & CCR_SUSP) && (ccr & CCR_EN)) {
>>>> + /* Suspend the channel */
>>>> + ret = stm32_dma3_chan_suspend(chan, true);
>>>> + if (ret)
>>>> + dev_warn(chan2dev(chan), "%s: timeout, data might be lost\n", __func__);
>>>> + }
>>>> +
>>>> + /*
>>>> + * Reset the channel: this causes the reset of the FIFO and the reset of the channel
>>>> + * internal state, the reset of CCR_EN and CCR_SUSP bits.
>>>> + */
>>>> + stm32_dma3_chan_reset(chan);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +static void stm32_dma3_chan_complete(struct stm32_dma3_chan *chan)
>>>> +{
>>>> + if (!chan->swdesc)
>>>> + return;
>>>> +
>>>> + vchan_cookie_complete(&chan->swdesc->vdesc);
>>>> + chan->swdesc = NULL;
>>>> + stm32_dma3_chan_start(chan);
>>>> +}
>>>> +
>>>> +static irqreturn_t stm32_dma3_chan_irq(int irq, void *devid)
>>>> +{
>>>> + struct stm32_dma3_chan *chan = devid;
>>>> + struct stm32_dma3_ddata *ddata = to_stm32_dma3_ddata(chan);
>>>> + u32 misr, csr, ccr;
>>>> +
>>>> + spin_lock(&chan->vchan.lock);
>>>> +
>>>> + misr = readl_relaxed(ddata->base + STM32_DMA3_MISR);
>>>> + if (!(misr & MISR_MIS(chan->id))) {
>>>> + spin_unlock(&chan->vchan.lock);
>>>> + return IRQ_NONE;
>>>> + }
>>>> +
>>>> + csr = readl_relaxed(ddata->base + STM32_DMA3_CSR(chan->id));
>>>> + ccr = readl_relaxed(ddata->base + STM32_DMA3_CCR(chan->id)) & CCR_ALLIE;
>>>> +
>>>> + if (csr & CSR_TCF && ccr & CCR_TCIE) {
>>>> + if (chan->swdesc->cyclic)
>>>> + vchan_cyclic_callback(&chan->swdesc->vdesc);
>>>> + else
>>>> + stm32_dma3_chan_complete(chan);
>>>> + }
>>>> +
>>>> + if (csr & CSR_USEF && ccr & CCR_USEIE) {
>>>> + dev_err(chan2dev(chan), "User setting error\n");
>>>> + chan->dma_status = DMA_ERROR;
>>>> + /* CCR.EN automatically cleared by HW */
>>>> + stm32_dma3_check_user_setting(chan);
>>>> + stm32_dma3_chan_reset(chan);
>>>> + }
>>>> +
>>>> + if (csr & CSR_ULEF && ccr & CCR_ULEIE) {
>>>> + dev_err(chan2dev(chan), "Update link transfer error\n");
>>>> + chan->dma_status = DMA_ERROR;
>>>> + /* CCR.EN automatically cleared by HW */
>>>> + stm32_dma3_chan_reset(chan);
>>>> + }
>>>> +
>>>> + if (csr & CSR_DTEF && ccr & CCR_DTEIE) {
>>>> + dev_err(chan2dev(chan), "Data transfer error\n");
>>>> + chan->dma_status = DMA_ERROR;
>>>> + /* CCR.EN automatically cleared by HW */
>>>> + stm32_dma3_chan_reset(chan);
>>>> + }
>>>> +
>>>> + /*
>>>> + * Half Transfer Interrupt may be disabled but Half Transfer Flag can be set,
>>>> + * ensure HTF flag to be cleared, with other flags.
>>>> + */
>>>> + csr &= (ccr | CCR_HTIE);
>>>> +
>>>> + if (csr)
>>>> + writel_relaxed(csr, ddata->base + STM32_DMA3_CFCR(chan->id));
>>>> +
>>>> + spin_unlock(&chan->vchan.lock);
>>>> +
>>>> + return IRQ_HANDLED;
>>>> +}
>>>> +
>>>> +static int stm32_dma3_alloc_chan_resources(struct dma_chan *c)
>>>> +{
>>>> + struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
>>>> + struct stm32_dma3_ddata *ddata = to_stm32_dma3_ddata(chan);
>>>> + u32 id = chan->id, csemcr, ccid;
>>>> + int ret;
>>>> +
>>>> + ret = pm_runtime_resume_and_get(ddata->dma_dev.dev);
>>>> + if (ret < 0)
>>>> + return ret;
>>>
>>> It doesn't prefer runtime pm get at alloc dma chan, many client driver
>>> doesn't actual user dma when allocate dma chan.
>>>
>>> Ideally, resume get when issue_pending. Please refer pl330.c.
>>>
>>> You may add runtime pm later after enablement patch.
>>>
>>> Frank
>>>
>>
>> To well balance clock enable/disable, if pm_runtime_resume_and_get() (rather
>> than pm_runtime_get_sync() which doesn't decrement the counter in case of
>> error) is used when issue_pending, it means pm_runtime_put_sync() should be
>> done when transfer ends.
>>
>> terminate_all is not always called, so put_sync can't be used only there, it
>> should be conditionnally used in terminate_all, but also in interrupt
>> handler, on error events and on transfer completion event, provided that it
>> is the last transfer complete event (last item of the linked-list).
>>
>> For clients with high transfer rate, it means a lot of clock enable/disable.
>> Moreover, DMA3 clock is managed by Secure OS. So it means a lot of
>> non-secure/secure world transitions.
>>
>> I prefer to keep the implementation as it is for now, and possibly propose
>> runtime pm improvement later, with autosuspend.
>
>
> Autosuspend is perfered. we try to use pm_runtime_get/put at channel alloc
> /free before, but this solution are rejected by community.
>
> you can leave clock on for this enablement patch and add runtime pm later
> time.
>
> Frank
>

Current implementation leaves the clock off if no channel is requested.
It also disables the clock if platform is suspended.
I just took example from what is done in stm32 drivers.

I have further patches, not proposed in this series which adds a basic
support of DMA3. There will be improvements, including runtime pm, in
next series.

Amelie

>>
>> Amelie
>>
>>>> +
>>>> + /* Ensure the channel is free */
>>>> + if (chan->semaphore_mode &&
>>>> + readl_relaxed(ddata->base + STM32_DMA3_CSEMCR(chan->id)) & CSEMCR_SEM_MUTEX) {
>>>> + ret = -EBUSY;
>>>> + goto err_put_sync;
>>>> + }
>>>> +
>>>> + chan->lli_pool = dmam_pool_create(dev_name(&c->dev->device), c->device->dev,
>>>> + sizeof(struct stm32_dma3_hwdesc),
>>>> + __alignof__(struct stm32_dma3_hwdesc), 0);
>>>> + if (!chan->lli_pool) {
>>>> + dev_err(chan2dev(chan), "Failed to create LLI pool\n");
>>>> + ret = -ENOMEM;
>>>> + goto err_put_sync;
>>>> + }
>>>> +
>>>> + /* Take the channel semaphore */
>>>> + if (chan->semaphore_mode) {
>>>> + writel_relaxed(CSEMCR_SEM_MUTEX, ddata->base + STM32_DMA3_CSEMCR(id));
>>>> + csemcr = readl_relaxed(ddata->base + STM32_DMA3_CSEMCR(id));
>>>> + ccid = FIELD_GET(CSEMCR_SEM_CCID, csemcr);
>>>> + /* Check that the channel is well taken */
>>>> + if (ccid != CCIDCFGR_CID1) {
>>>> + dev_err(chan2dev(chan), "Not under CID1 control (in-use by CID%d)\n", ccid);
>>>> + ret = -EPERM;
>>>> + goto err_pool_destroy;
>>>> + }
>>>> + dev_dbg(chan2dev(chan), "Under CID1 control (semcr=0x%08x)\n", csemcr);
>>>> + }
>>>> +
>>>> + return 0;
>>>> +
>>>> +err_pool_destroy:
>>>> + dmam_pool_destroy(chan->lli_pool);
>>>> + chan->lli_pool = NULL;
>>>> +
>>>> +err_put_sync:
>>>> + pm_runtime_put_sync(ddata->dma_dev.dev);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +static void stm32_dma3_free_chan_resources(struct dma_chan *c)
>>>> +{
>>>> + struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
>>>> + struct stm32_dma3_ddata *ddata = to_stm32_dma3_ddata(chan);
>>>> + unsigned long flags;
>>>> +
>>>> + /* Ensure channel is in idle state */
>>>> + spin_lock_irqsave(&chan->vchan.lock, flags);
>>>> + stm32_dma3_chan_stop(chan);
>>>> + chan->swdesc = NULL;
>>>> + spin_unlock_irqrestore(&chan->vchan.lock, flags);
>>>> +
>>>> + vchan_free_chan_resources(to_virt_chan(c));
>>>> +
>>>> + dmam_pool_destroy(chan->lli_pool);
>>>> + chan->lli_pool = NULL;
>>>> +
>>>> + /* Release the channel semaphore */
>>>> + if (chan->semaphore_mode)
>>>> + writel_relaxed(0, ddata->base + STM32_DMA3_CSEMCR(chan->id));
>>>> +
>>>> + pm_runtime_put_sync(ddata->dma_dev.dev);
>>>> +
>>>> + /* Reset configuration */
>>>> + memset(&chan->dt_config, 0, sizeof(chan->dt_config));
>>>> + memset(&chan->dma_config, 0, sizeof(chan->dma_config));
>>>> +}
>>>> +
>>>> +static struct dma_async_tx_descriptor *stm32_dma3_prep_slave_sg(struct dma_chan *c,
>>>> + struct scatterlist *sgl,
>>>> + unsigned int sg_len,
>>>> + enum dma_transfer_direction dir,
>>>> + unsigned long flags, void *context)
>>>> +{
>>>> + struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
>>>> + struct stm32_dma3_swdesc *swdesc;
>>>> + struct scatterlist *sg;
>>>> + size_t len;
>>>> + dma_addr_t sg_addr, dev_addr, src, dst;
>>>> + u32 i, j, count, ctr1, ctr2;
>>>> + int ret;
>>>> +
>>>> + count = sg_len;
>>>> + for_each_sg(sgl, sg, sg_len, i) {
>>>> + len = sg_dma_len(sg);
>>>> + if (len > STM32_DMA3_MAX_BLOCK_SIZE)
>>>> + count += DIV_ROUND_UP(len, STM32_DMA3_MAX_BLOCK_SIZE) - 1;
>>>> + }
>>>> +
>>>> + swdesc = stm32_dma3_chan_desc_alloc(chan, count);
>>>> + if (!swdesc)
>>>> + return NULL;
>>>> +
>>>> + /* sg_len and i correspond to the initial sgl; count and j correspond to the hwdesc LL */
>>>> + j = 0;
>>>> + for_each_sg(sgl, sg, sg_len, i) {
>>>> + sg_addr = sg_dma_address(sg);
>>>> + dev_addr = (dir == DMA_MEM_TO_DEV) ? chan->dma_config.dst_addr :
>>>> + chan->dma_config.src_addr;
>>>> + len = sg_dma_len(sg);
>>>> +
>>>> + do {
>>>> + size_t chunk = min_t(size_t, len, STM32_DMA3_MAX_BLOCK_SIZE);
>>>> +
>>>> + if (dir == DMA_MEM_TO_DEV) {
>>>> + src = sg_addr;
>>>> + dst = dev_addr;
>>>> +
>>>> + ret = stm32_dma3_chan_prep_hw(chan, dir, &swdesc->ccr, &ctr1, &ctr2,
>>>> + src, dst, chunk);
>>>> +
>>>> + if (FIELD_GET(CTR1_DINC, ctr1))
>>>> + dev_addr += chunk;
>>>> + } else { /* (dir == DMA_DEV_TO_MEM || dir == DMA_MEM_TO_MEM) */
>>>> + src = dev_addr;
>>>> + dst = sg_addr;
>>>> +
>>>> + ret = stm32_dma3_chan_prep_hw(chan, dir, &swdesc->ccr, &ctr1, &ctr2,
>>>> + src, dst, chunk);
>>>> +
>>>> + if (FIELD_GET(CTR1_SINC, ctr1))
>>>> + dev_addr += chunk;
>>>> + }
>>>> +
>>>> + if (ret)
>>>> + goto err_desc_free;
>>>> +
>>>> + stm32_dma3_chan_prep_hwdesc(chan, swdesc, j, src, dst, chunk,
>>>> + ctr1, ctr2, j == (count - 1), false);
>>>> +
>>>> + sg_addr += chunk;
>>>> + len -= chunk;
>>>> + j++;
>>>> + } while (len);
>>>> + }
>>>> +
>>>> + /* Enable Error interrupts */
>>>> + swdesc->ccr |= CCR_USEIE | CCR_ULEIE | CCR_DTEIE;
>>>> + /* Enable Transfer state interrupts */
>>>> + swdesc->ccr |= CCR_TCIE;
>>>> +
>>>> + swdesc->cyclic = false;
>>>> +
>>>> + return vchan_tx_prep(&chan->vchan, &swdesc->vdesc, flags);
>>>> +
>>>> +err_desc_free:
>>>> + stm32_dma3_chan_desc_free(chan, swdesc);
>>>> +
>>>> + return NULL;
>>>> +}
>>>> +
>>>> +static void stm32_dma3_caps(struct dma_chan *c, struct dma_slave_caps *caps)
>>>> +{
>>>> + struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
>>>> +
>>>> + if (!chan->fifo_size) {
>>>> + caps->max_burst = 0;
>>>> + caps->src_addr_widths &= ~BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
>>>> + caps->dst_addr_widths &= ~BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
>>>> + } else {
>>>> + /* Burst transfer should not exceed half of the fifo size */
>>>> + caps->max_burst = chan->max_burst;
>>>> + if (caps->max_burst < DMA_SLAVE_BUSWIDTH_8_BYTES) {
>>>> + caps->src_addr_widths &= ~BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
>>>> + caps->dst_addr_widths &= ~BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
>>>> + }
>>>> + }
>>>> +}
>>>> +
>>>> +static int stm32_dma3_config(struct dma_chan *c, struct dma_slave_config *config)
>>>> +{
>>>> + struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
>>>> +
>>>> + memcpy(&chan->dma_config, config, sizeof(*config));
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int stm32_dma3_terminate_all(struct dma_chan *c)
>>>> +{
>>>> + struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
>>>> + unsigned long flags;
>>>> + LIST_HEAD(head);
>>>> +
>>>> + spin_lock_irqsave(&chan->vchan.lock, flags);
>>>> +
>>>> + if (chan->swdesc) {
>>>> + vchan_terminate_vdesc(&chan->swdesc->vdesc);
>>>> + chan->swdesc = NULL;
>>>> + }
>>>> +
>>>> + stm32_dma3_chan_stop(chan);
>>>> +
>>>> + vchan_get_all_descriptors(&chan->vchan, &head);
>>>> +
>>>> + spin_unlock_irqrestore(&chan->vchan.lock, flags);
>>>> + vchan_dma_desc_free_list(&chan->vchan, &head);
>>>> +
>>>> + dev_dbg(chan2dev(chan), "vchan %pK: terminated\n", &chan->vchan);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static void stm32_dma3_synchronize(struct dma_chan *c)
>>>> +{
>>>> + struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
>>>> +
>>>> + vchan_synchronize(&chan->vchan);
>>>> +}
>>>> +
>>>> +static void stm32_dma3_issue_pending(struct dma_chan *c)
>>>> +{
>>>> + struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
>>>> + unsigned long flags;
>>>> +
>>>> + spin_lock_irqsave(&chan->vchan.lock, flags);
>>>> +
>>>> + if (vchan_issue_pending(&chan->vchan) && !chan->swdesc) {
>>>> + dev_dbg(chan2dev(chan), "vchan %pK: issued\n", &chan->vchan);
>>>> + stm32_dma3_chan_start(chan);
>>>> + }
>>>> +
>>>> + spin_unlock_irqrestore(&chan->vchan.lock, flags);
>>>> +}
>>>> +
>>>> +static bool stm32_dma3_filter_fn(struct dma_chan *c, void *fn_param)
>>>> +{
>>>> + struct stm32_dma3_chan *chan = to_stm32_dma3_chan(c);
>>>> + struct stm32_dma3_ddata *ddata = to_stm32_dma3_ddata(chan);
>>>> + struct stm32_dma3_dt_conf *conf = fn_param;
>>>> + u32 mask, semcr;
>>>> + int ret;
>>>> +
>>>> + dev_dbg(c->device->dev, "%s(%s): req_line=%d ch_conf=%08x tr_conf=%08x\n",
>>>> + __func__, dma_chan_name(c), conf->req_line, conf->ch_conf, conf->tr_conf);
>>>> +
>>>> + if (!of_property_read_u32(c->device->dev->of_node, "dma-channel-mask", &mask))
>>>> + if (!(mask & BIT(chan->id)))
>>>> + return false;
>>>> +
>>>> + ret = pm_runtime_resume_and_get(ddata->dma_dev.dev);
>>>> + if (ret < 0)
>>>> + return false;
>>>> + semcr = readl_relaxed(ddata->base + STM32_DMA3_CSEMCR(chan->id));
>>>> + pm_runtime_put_sync(ddata->dma_dev.dev);
>>>> +
>>>> + /* Check if chan is free */
>>>> + if (semcr & CSEMCR_SEM_MUTEX)
>>>> + return false;
>>>> +
>>>> + /* Check if chan fifo fits well */
>>>> + if (FIELD_GET(STM32_DMA3_DT_FIFO, conf->ch_conf) != chan->fifo_size)
>>>> + return false;
>>>> +
>>>> + return true;
>>>> +}
>>>> +
>>>> +static struct dma_chan *stm32_dma3_of_xlate(struct of_phandle_args *dma_spec, struct of_dma *ofdma)
>>>> +{
>>>> + struct stm32_dma3_ddata *ddata = ofdma->of_dma_data;
>>>> + dma_cap_mask_t mask = ddata->dma_dev.cap_mask;
>>>> + struct stm32_dma3_dt_conf conf;
>>>> + struct stm32_dma3_chan *chan;
>>>> + struct dma_chan *c;
>>>> +
>>>> + if (dma_spec->args_count < 3) {
>>>> + dev_err(ddata->dma_dev.dev, "Invalid args count\n");
>>>> + return NULL;
>>>> + }
>>>> +
>>>> + conf.req_line = dma_spec->args[0];
>>>> + conf.ch_conf = dma_spec->args[1];
>>>> + conf.tr_conf = dma_spec->args[2];
>>>> +
>>>> + if (conf.req_line >= ddata->dma_requests) {
>>>> + dev_err(ddata->dma_dev.dev, "Invalid request line\n");
>>>> + return NULL;
>>>> + }
>>>> +
>>>> + /* Request dma channel among the generic dma controller list */
>>>> + c = dma_request_channel(mask, stm32_dma3_filter_fn, &conf);
>>>> + if (!c) {
>>>> + dev_err(ddata->dma_dev.dev, "No suitable channel found\n");
>>>> + return NULL;
>>>> + }
>>>> +
>>>> + chan = to_stm32_dma3_chan(c);
>>>> + chan->dt_config = conf;
>>>> +
>>>> + return c;
>>>> +}
>>>> +
>>>> +static u32 stm32_dma3_check_rif(struct stm32_dma3_ddata *ddata)
>>>> +{
>>>> + u32 chan_reserved, mask = 0, i, ccidcfgr, invalid_cid = 0;
>>>> +
>>>> + /* Reserve Secure channels */
>>>> + chan_reserved = readl_relaxed(ddata->base + STM32_DMA3_SECCFGR);
>>>> +
>>>> + /*
>>>> + * CID filtering must be configured to ensure that the DMA3 channel will inherit the CID of
>>>> + * the processor which is configuring and using the given channel.
>>>> + * In case CID filtering is not configured, dma-channel-mask property can be used to
>>>> + * specify available DMA channels to the kernel.
>>>> + */
>>>> + of_property_read_u32(ddata->dma_dev.dev->of_node, "dma-channel-mask", &mask);
>>>> +
>>>> + /* Reserve !CID-filtered not in dma-channel-mask, static CID != CID1, CID1 not allowed */
>>>> + for (i = 0; i < ddata->dma_channels; i++) {
>>>> + ccidcfgr = readl_relaxed(ddata->base + STM32_DMA3_CCIDCFGR(i));
>>>> +
>>>> + if (!(ccidcfgr & CCIDCFGR_CFEN)) { /* !CID-filtered */
>>>> + invalid_cid |= BIT(i);
>>>> + if (!(mask & BIT(i))) /* Not in dma-channel-mask */
>>>> + chan_reserved |= BIT(i);
>>>> + } else { /* CID-filtered */
>>>> + if (!(ccidcfgr & CCIDCFGR_SEM_EN)) { /* Static CID mode */
>>>> + if (FIELD_GET(CCIDCFGR_SCID, ccidcfgr) != CCIDCFGR_CID1)
>>>> + chan_reserved |= BIT(i);
>>>> + } else { /* Semaphore mode */
>>>> + if (!FIELD_GET(CCIDCFGR_SEM_WLIST_CID1, ccidcfgr))
>>>> + chan_reserved |= BIT(i);
>>>> + ddata->chans[i].semaphore_mode = true;
>>>> + }
>>>> + }
>>>> + dev_dbg(ddata->dma_dev.dev, "chan%d: %s mode, %s\n", i,
>>>> + !(ccidcfgr & CCIDCFGR_CFEN) ? "!CID-filtered" :
>>>> + ddata->chans[i].semaphore_mode ? "Semaphore" : "Static CID",
>>>> + (chan_reserved & BIT(i)) ? "denied" :
>>>> + mask & BIT(i) ? "force allowed" : "allowed");
>>>> + }
>>>> +
>>>> + if (invalid_cid)
>>>> + dev_warn(ddata->dma_dev.dev, "chan%*pbl have invalid CID configuration\n",
>>>> + ddata->dma_channels, &invalid_cid);
>>>> +
>>>> + return chan_reserved;
>>>> +}
>>>> +
>>>> +static const struct of_device_id stm32_dma3_of_match[] = {
>>>> + { .compatible = "st,stm32-dma3", },
>>>> + { /* sentinel */},
>>>> +};
>>>> +MODULE_DEVICE_TABLE(of, stm32_dma3_of_match);
>>>> +
>>>> +static int stm32_dma3_probe(struct platform_device *pdev)
>>>> +{
>>>> + struct device_node *np = pdev->dev.of_node;
>>>> + struct stm32_dma3_ddata *ddata;
>>>> + struct reset_control *reset;
>>>> + struct stm32_dma3_chan *chan;
>>>> + struct dma_device *dma_dev;
>>>> + u32 master_ports, chan_reserved, i, verr;
>>>> + u64 hwcfgr;
>>>> + int ret;
>>>> +
>>>> + ddata = devm_kzalloc(&pdev->dev, sizeof(*ddata), GFP_KERNEL);
>>>> + if (!ddata)
>>>> + return -ENOMEM;
>>>> + platform_set_drvdata(pdev, ddata);
>>>> +
>>>> + dma_dev = &ddata->dma_dev;
>>>> +
>>>> + ddata->base = devm_platform_ioremap_resource(pdev, 0);
>>>> + if (IS_ERR(ddata->base))
>>>> + return PTR_ERR(ddata->base);
>>>> +
>>>> + ddata->clk = devm_clk_get(&pdev->dev, NULL);
>>>> + if (IS_ERR(ddata->clk))
>>>> + return dev_err_probe(&pdev->dev, PTR_ERR(ddata->clk), "Failed to get clk\n");
>>>> +
>>>> + reset = devm_reset_control_get_optional(&pdev->dev, NULL);
>>>> + if (IS_ERR(reset))
>>>> + return dev_err_probe(&pdev->dev, PTR_ERR(reset), "Failed to get reset\n");
>>>> +
>>>> + ret = clk_prepare_enable(ddata->clk);
>>>> + if (ret)
>>>> + return dev_err_probe(&pdev->dev, ret, "Failed to enable clk\n");
>>>> +
>>>> + reset_control_reset(reset);
>>>> +
>>>> + INIT_LIST_HEAD(&dma_dev->channels);
>>>> +
>>>> + dma_cap_set(DMA_SLAVE, dma_dev->cap_mask);
>>>> + dma_cap_set(DMA_PRIVATE, dma_dev->cap_mask);
>>>> + dma_dev->dev = &pdev->dev;
>>>> + /*
>>>> + * This controller supports up to 8-byte buswidth depending on the port used and the
>>>> + * channel, and can only access address at even boundaries, multiple of the buswidth.
>>>> + */
>>>> + dma_dev->copy_align = DMAENGINE_ALIGN_8_BYTES;
>>>> + dma_dev->src_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
>>>> + BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
>>>> + BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |
>>>> + BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
>>>> + dma_dev->dst_addr_widths = BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
>>>> + BIT(DMA_SLAVE_BUSWIDTH_2_BYTES) |
>>>> + BIT(DMA_SLAVE_BUSWIDTH_4_BYTES) |
>>>> + BIT(DMA_SLAVE_BUSWIDTH_8_BYTES);
>>>> + dma_dev->directions = BIT(DMA_DEV_TO_MEM) | BIT(DMA_MEM_TO_DEV) | BIT(DMA_MEM_TO_MEM);
>>>> +
>>>> + dma_dev->descriptor_reuse = true;
>>>> + dma_dev->max_sg_burst = STM32_DMA3_MAX_SEG_SIZE;
>>>> + dma_dev->residue_granularity = DMA_RESIDUE_GRANULARITY_DESCRIPTOR;
>>>> + dma_dev->device_alloc_chan_resources = stm32_dma3_alloc_chan_resources;
>>>> + dma_dev->device_free_chan_resources = stm32_dma3_free_chan_resources;
>>>> + dma_dev->device_prep_slave_sg = stm32_dma3_prep_slave_sg;
>>>> + dma_dev->device_caps = stm32_dma3_caps;
>>>> + dma_dev->device_config = stm32_dma3_config;
>>>> + dma_dev->device_terminate_all = stm32_dma3_terminate_all;
>>>> + dma_dev->device_synchronize = stm32_dma3_synchronize;
>>>> + dma_dev->device_tx_status = dma_cookie_status;
>>>> + dma_dev->device_issue_pending = stm32_dma3_issue_pending;
>>>> +
>>>> + /* if dma_channels is not modified, get it from hwcfgr1 */
>>>> + if (of_property_read_u32(np, "dma-channels", &ddata->dma_channels)) {
>>>> + hwcfgr = readl_relaxed(ddata->base + STM32_DMA3_HWCFGR1);
>>>> + ddata->dma_channels = FIELD_GET(G_NUM_CHANNELS, hwcfgr);
>>>> + }
>>>> +
>>>> + /* if dma_requests is not modified, get it from hwcfgr2 */
>>>> + if (of_property_read_u32(np, "dma-requests", &ddata->dma_requests)) {
>>>> + hwcfgr = readl_relaxed(ddata->base + STM32_DMA3_HWCFGR2);
>>>> + ddata->dma_requests = FIELD_GET(G_MAX_REQ_ID, hwcfgr) + 1;
>>>> + }
>>>> +
>>>> + /* G_MASTER_PORTS, G_M0_DATA_WIDTH_ENC, G_M1_DATA_WIDTH_ENC in HWCFGR1 */
>>>> + hwcfgr = readl_relaxed(ddata->base + STM32_DMA3_HWCFGR1);
>>>> + master_ports = FIELD_GET(G_MASTER_PORTS, hwcfgr);
>>>> +
>>>> + ddata->ports_max_dw[0] = FIELD_GET(G_M0_DATA_WIDTH_ENC, hwcfgr);
>>>> + if (master_ports == AXI64 || master_ports == AHB32) /* Single master port */
>>>> + ddata->ports_max_dw[1] = DW_INVALID;
>>>> + else /* Dual master ports */
>>>> + ddata->ports_max_dw[1] = FIELD_GET(G_M1_DATA_WIDTH_ENC, hwcfgr);
>>>> +
>>>> + ddata->chans = devm_kcalloc(&pdev->dev, ddata->dma_channels, sizeof(*ddata->chans),
>>>> + GFP_KERNEL);
>>>> + if (!ddata->chans) {
>>>> + ret = -ENOMEM;
>>>> + goto err_clk_disable;
>>>> + }
>>>> +
>>>> + chan_reserved = stm32_dma3_check_rif(ddata);
>>>> +
>>>> + if (chan_reserved == GENMASK(ddata->dma_channels - 1, 0)) {
>>>> + ret = -ENODEV;
>>>> + dev_err_probe(&pdev->dev, ret, "No channel available, abort registration\n");
>>>> + goto err_clk_disable;
>>>> + }
>>>> +
>>>> + /* G_FIFO_SIZE x=0..7 in HWCFGR3 and G_FIFO_SIZE x=8..15 in HWCFGR4 */
>>>> + hwcfgr = readl_relaxed(ddata->base + STM32_DMA3_HWCFGR3);
>>>> + hwcfgr |= ((u64)readl_relaxed(ddata->base + STM32_DMA3_HWCFGR4)) << 32;
>>>> +
>>>> + for (i = 0; i < ddata->dma_channels; i++) {
>>>> + if (chan_reserved & BIT(i))
>>>> + continue;
>>>> +
>>>> + chan = &ddata->chans[i];
>>>> + chan->id = i;
>>>> + chan->fifo_size = get_chan_hwcfg(i, G_FIFO_SIZE(i), hwcfgr);
>>>> + /* If chan->fifo_size > 0 then half of the fifo size, else no burst when no FIFO */
>>>> + chan->max_burst = (chan->fifo_size) ? (1 << (chan->fifo_size + 1)) / 2 : 0;
>>>> + chan->vchan.desc_free = stm32_dma3_chan_vdesc_free;
>>>> +
>>>> + vchan_init(&chan->vchan, dma_dev);
>>>> + }
>>>> +
>>>> + ret = dmaenginem_async_device_register(dma_dev);
>>>> + if (ret)
>>>> + goto err_clk_disable;
>>>> +
>>>> + for (i = 0; i < ddata->dma_channels; i++) {
>>>> + if (chan_reserved & BIT(i))
>>>> + continue;
>>>> +
>>>> + ret = platform_get_irq(pdev, i);
>>>> + if (ret < 0)
>>>> + goto err_clk_disable;
>>>> +
>>>> + chan = &ddata->chans[i];
>>>> + chan->irq = ret;
>>>> +
>>>> + ret = devm_request_irq(&pdev->dev, chan->irq, stm32_dma3_chan_irq, 0,
>>>> + dev_name(chan2dev(chan)), chan);
>>>> + if (ret) {
>>>> + dev_err_probe(&pdev->dev, ret, "Failed to request channel %s IRQ\n",
>>>> + dev_name(chan2dev(chan)));
>>>> + goto err_clk_disable;
>>>> + }
>>>> + }
>>>> +
>>>> + ret = of_dma_controller_register(np, stm32_dma3_of_xlate, ddata);
>>>> + if (ret) {
>>>> + dev_err_probe(&pdev->dev, ret, "Failed to register controller\n");
>>>> + goto err_clk_disable;
>>>> + }
>>>> +
>>>> + verr = readl_relaxed(ddata->base + STM32_DMA3_VERR);
>>>> +
>>>> + pm_runtime_set_active(&pdev->dev);
>>>> + pm_runtime_enable(&pdev->dev);
>>>> + pm_runtime_get_noresume(&pdev->dev);
>>>> + pm_runtime_put(&pdev->dev);
>>>> +
>>>> + dev_info(&pdev->dev, "STM32 DMA3 registered rev:%lu.%lu\n",
>>>> + FIELD_GET(VERR_MAJREV, verr), FIELD_GET(VERR_MINREV, verr));
>>>> +
>>>> + return 0;
>>>> +
>>>> +err_clk_disable:
>>>> + clk_disable_unprepare(ddata->clk);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +static void stm32_dma3_remove(struct platform_device *pdev)
>>>> +{
>>>> + pm_runtime_disable(&pdev->dev);
>>>> +}
>>>> +
>>>> +static int stm32_dma3_runtime_suspend(struct device *dev)
>>>> +{
>>>> + struct stm32_dma3_ddata *ddata = dev_get_drvdata(dev);
>>>> +
>>>> + clk_disable_unprepare(ddata->clk);
>>>> +
>>>> + return 0;
>>>> +}
>>>> +
>>>> +static int stm32_dma3_runtime_resume(struct device *dev)
>>>> +{
>>>> + struct stm32_dma3_ddata *ddata = dev_get_drvdata(dev);
>>>> + int ret;
>>>> +
>>>> + ret = clk_prepare_enable(ddata->clk);
>>>> + if (ret)
>>>> + dev_err(dev, "Failed to enable clk: %d\n", ret);
>>>> +
>>>> + return ret;
>>>> +}
>>>> +
>>>> +static const struct dev_pm_ops stm32_dma3_pm_ops = {
>>>> + SYSTEM_SLEEP_PM_OPS(pm_runtime_force_suspend, pm_runtime_force_resume)
>>>> + RUNTIME_PM_OPS(stm32_dma3_runtime_suspend, stm32_dma3_runtime_resume, NULL)
>>>> +};
>>>> +
>>>> +static struct platform_driver stm32_dma3_driver = {
>>>> + .probe = stm32_dma3_probe,
>>>> + .remove_new = stm32_dma3_remove,
>>>> + .driver = {
>>>> + .name = "stm32-dma3",
>>>> + .of_match_table = stm32_dma3_of_match,
>>>> + .pm = pm_ptr(&stm32_dma3_pm_ops),
>>>> + },
>>>> +};
>>>> +
>>>> +static int __init stm32_dma3_init(void)
>>>> +{
>>>> + return platform_driver_register(&stm32_dma3_driver);
>>>> +}
>>>> +
>>>> +subsys_initcall(stm32_dma3_init);
>>>> +
>>>> +MODULE_DESCRIPTION("STM32 DMA3 controller driver");
>>>> +MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@foss.st.com>");
>>>> +MODULE_LICENSE("GPL");
>>>> --
>>>> 2.25.1
>>>>

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