diff mbox series

[v8,4/4] dmaengine: sf-pdma: Get number of channel by device tree

Message ID f08a95b6582a51712c5b2c3cb859136d07bfa8b9.1648461096.git.zong.li@sifive.com (mailing list archive)
State New, archived
Headers show
Series Determine the number of DMA channels by 'dma-channels' property | expand

Commit Message

Zong Li March 28, 2022, 9:52 a.m. UTC 
It currently assumes that there are always four channels, it would
cause the error if there is actually less than four channels. Change
that by getting number of channel from device tree.

For backwards-compatibility, it uses the default value (i.e. 4) when
there is no 'dma-channels' information in dts.

Signed-off-by: Zong Li <zong.li@sifive.com>
Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
---
 drivers/dma/sf-pdma/sf-pdma.c | 24 ++++++++++++++++--------
 drivers/dma/sf-pdma/sf-pdma.h |  8 ++------
 2 files changed, 18 insertions(+), 14 deletions(-)

Comments

Bin Meng March 29, 2022, 1:35 a.m. UTC | #1 
On Mon, Mar 28, 2022 at 7:38 PM Zong Li <zong.li@sifive.com> wrote:
>
> It currently assumes that there are always four channels, it would
> cause the error if there is actually less than four channels. Change
> that by getting number of channel from device tree.
>
> For backwards-compatibility, it uses the default value (i.e. 4) when
> there is no 'dma-channels' information in dts.
>
> Signed-off-by: Zong Li <zong.li@sifive.com>
> Acked-by: Palmer Dabbelt <palmer@rivosinc.com>
> ---
>  drivers/dma/sf-pdma/sf-pdma.c | 24 ++++++++++++++++--------
>  drivers/dma/sf-pdma/sf-pdma.h |  8 ++------
>  2 files changed, 18 insertions(+), 14 deletions(-)
>

Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
diff mbox series

Patch

diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c
index f12606aeff87..db5a4ef76077 100644
--- a/drivers/dma/sf-pdma/sf-pdma.c
+++ b/drivers/dma/sf-pdma/sf-pdma.c
@@ -482,23 +482,30 @@  static void sf_pdma_setup_chans(struct sf_pdma *pdma)
 static int sf_pdma_probe(struct platform_device *pdev)
 {
 	struct sf_pdma *pdma;
-	struct sf_pdma_chan *chan;
 	struct resource *res;
-	int len, chans;
-	int ret;
+	int ret, n_chans;
 	const enum dma_slave_buswidth widths =
 		DMA_SLAVE_BUSWIDTH_1_BYTE | DMA_SLAVE_BUSWIDTH_2_BYTES |
 		DMA_SLAVE_BUSWIDTH_4_BYTES | DMA_SLAVE_BUSWIDTH_8_BYTES |
 		DMA_SLAVE_BUSWIDTH_16_BYTES | DMA_SLAVE_BUSWIDTH_32_BYTES |
 		DMA_SLAVE_BUSWIDTH_64_BYTES;
 
-	chans = PDMA_NR_CH;
-	len = sizeof(*pdma) + sizeof(*chan) * chans;
-	pdma = devm_kzalloc(&pdev->dev, len, GFP_KERNEL);
+	ret = of_property_read_u32(pdev->dev.of_node, "dma-channels", &n_chans);
+	if (ret) {
+		/* backwards-compatibility for no dma-channels property */
+		dev_dbg(&pdev->dev, "set number of channels to default value: 4\n");
+		n_chans = PDMA_MAX_NR_CH;
+	} else if (n_chans > PDMA_MAX_NR_CH) {
+		dev_err(&pdev->dev, "the number of channels exceeds the maximum\n");
+		return -EINVAL;
+	}
+
+	pdma = devm_kzalloc(&pdev->dev, struct_size(pdma, chans, n_chans),
+			    GFP_KERNEL);
 	if (!pdma)
 		return -ENOMEM;
 
-	pdma->n_chans = chans;
+	pdma->n_chans = n_chans;
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	pdma->membase = devm_ioremap_resource(&pdev->dev, res);
@@ -556,7 +563,7 @@  static int sf_pdma_remove(struct platform_device *pdev)
 	struct sf_pdma_chan *ch;
 	int i;
 
-	for (i = 0; i < PDMA_NR_CH; i++) {
+	for (i = 0; i < pdma->n_chans; i++) {
 		ch = &pdma->chans[i];
 
 		devm_free_irq(&pdev->dev, ch->txirq, ch);
@@ -574,6 +581,7 @@  static int sf_pdma_remove(struct platform_device *pdev)
 
 static const struct of_device_id sf_pdma_dt_ids[] = {
 	{ .compatible = "sifive,fu540-c000-pdma" },
+	{ .compatible = "sifive,pdma0" },
 	{},
 };
 MODULE_DEVICE_TABLE(of, sf_pdma_dt_ids);
diff --git a/drivers/dma/sf-pdma/sf-pdma.h b/drivers/dma/sf-pdma/sf-pdma.h
index 0c20167b097d..dcb3687bd5da 100644
--- a/drivers/dma/sf-pdma/sf-pdma.h
+++ b/drivers/dma/sf-pdma/sf-pdma.h
@@ -22,11 +22,7 @@ 
 #include "../dmaengine.h"
 #include "../virt-dma.h"
 
-#define PDMA_NR_CH					4
-
-#if (PDMA_NR_CH != 4)
-#error "Please define PDMA_NR_CH to 4"
-#endif
+#define PDMA_MAX_NR_CH					4
 
 #define PDMA_BASE_ADDR					0x3000000
 #define PDMA_CHAN_OFFSET				0x1000
@@ -118,7 +114,7 @@  struct sf_pdma {
 	void __iomem            *membase;
 	void __iomem            *mappedbase;
 	u32			n_chans;
-	struct sf_pdma_chan	chans[PDMA_NR_CH];
+	struct sf_pdma_chan	chans[];
 };
 
 #endif /* _SF_PDMA_H */