Re: [PATCH v4 02/10] dmaengine: Actions: Add support for S700 DMA engine
From: Vinod Koul <vkoul@kernel.org>
Date: 2020-06-24 06:15:36
Also in:
dmaengine, lkml
Hi Amit, On 09-06-20, 15:47, Amit Singh Tomar wrote:
quoted hunk ↗ jump to hunk
@@ -372,6 +383,7 @@ static inline int owl_dma_cfg_lli(struct owl_dma_vchan *vchan, struct dma_slave_config *sconfig, bool is_cyclic) { + struct owl_dma *od = to_owl_dma(vchan->vc.chan.device); u32 mode, ctrlb; mode = OWL_DMA_MODE_PW(0);@@ -427,14 +439,26 @@ static inline int owl_dma_cfg_lli(struct owl_dma_vchan *vchan, lli->hw[OWL_DMADESC_DADDR] = dst; lli->hw[OWL_DMADESC_SRC_STRIDE] = 0; lli->hw[OWL_DMADESC_DST_STRIDE] = 0; - /* - * Word starts from offset 0xC is shared between frame length - * (max frame length is 1MB) and frame count, where first 20 - * bits are for frame length and rest of 12 bits are for frame - * count. - */ - lli->hw[OWL_DMADESC_FLEN] = len | FCNT_VAL << 20; - lli->hw[OWL_DMADESC_CTRLB] = ctrlb; + + if (od->devid == S700_DMA) { + /* Max frame length is 1MB */ + lli->hw[OWL_DMADESC_FLEN] = len; + /* + * On S700, word starts from offset 0x1C is shared between + * frame count and ctrlb, where first 12 bits are for frame + * count and rest of 20 bits are for ctrlb. + */ + lli->hw[OWL_DMADESC_CTRLB] = FCNT_VAL | ctrlb; + } else { + /* + * On S900, word starts from offset 0xC is shared between + * frame length (max frame length is 1MB) and frame count, + * where first 20 bits are for frame length and rest of + * 12 bits are for frame count. + */ + lli->hw[OWL_DMADESC_FLEN] = len | FCNT_VAL << 20; + lli->hw[OWL_DMADESC_CTRLB] = ctrlb;
Unfortunately this wont scale, we will keep adding new conditions for newer SoC's! So rather than this why not encode max frame length in driver_data rather than S900_DMA/S700_DMA.. In future one can add values for newer SoC and not code above logic again.
+static const struct of_device_id owl_dma_match[] = {
+ { .compatible = "actions,s900-dma", .data = (void *)S900_DMA,},
+ { .compatible = "actions,s700-dma", .data = (void *)S700_DMA,},Is the .compatible documented, Documentation patch should come before the driver use patch in a series
static int owl_dma_probe(struct platform_device *pdev)
{
struct device_node *np = pdev->dev.of_node;
struct owl_dma *od;
int ret, i, nr_channels, nr_requests;
+ const struct of_device_id *of_id =
+ of_match_device(owl_dma_match, &pdev->dev);You care about driver_data rather than of_id, so using of_device_get_match_data() would be better..
quoted hunk ↗ jump to hunk
od = devm_kzalloc(&pdev->dev, sizeof(*od), GFP_KERNEL); if (!od)@@ -1083,6 +1116,8 @@ static int owl_dma_probe(struct platform_device *pdev) dev_info(&pdev->dev, "dma-channels %d, dma-requests %d\n", nr_channels, nr_requests); + od->devid = (enum owl_dma_id)(uintptr_t)of_id->data;
Funny casts, I dont think you need uintptr_t! -- ~Vinod _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel