dmaengine: sf-pdma: Get number of channel by device tree

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>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Link: https://lore.kernel.org/r/f08a95b6582a51712c5b2c3cb859136d07bfa8b9.1648461096.git.zong.li@sifive.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>

diff --git a/drivers/dma/sf-pdma/sf-pdma.c b/drivers/dma/sf-pdma/sf-pdma.c
index f12606a..db5a4ef 100644 (file)
--- 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 0c20167..dcb3687 100644 (file)
--- 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 */