Re: [PATCH RESEND] dmaengine: at_xdmac: get the number of DMA channels from device tree
From: Vinod Koul <vkoul@kernel.org>
Date: 2025-12-16 15:18:20
Also in:
dmaengine, lkml
On 03-12-25, 13:11, Robert Marko wrote:
From: Tony Han <redacted> In case of kernel runs in non-secure mode, the number of DMA channels can be got from device tree since the value read from GTYPE register is "0" as it's always secured. As the number of channels can never be negative, update them to the type "unsigned". This is required for LAN969x.
You updated the changelog, but tagged it as resend. It should be v2!
quoted hunk ↗ jump to hunk
Signed-off-by: Tony Han <redacted> Signed-off-by: Robert Marko <robert.marko@sartura.hr> --- drivers/dma/at_xdmac.c | 26 +++++++++++++++++++++++--- 1 file changed, 23 insertions(+), 3 deletions(-)diff --git a/drivers/dma/at_xdmac.c b/drivers/dma/at_xdmac.c index 3fbc74710a13..acabf82e293c 100644 --- a/drivers/dma/at_xdmac.c +++ b/drivers/dma/at_xdmac.c@@ -2257,12 +2257,29 @@ static int __maybe_unused atmel_xdmac_runtime_resume(struct device *dev) return clk_enable(atxdmac->clk); } +static inline int at_xdmac_get_channel_number(struct platform_device *pdev, + u32 reg, u32 *pchannels) +{ + int ret; + + if (reg) { + *pchannels = AT_XDMAC_NB_CH(reg); + return 0; + } + + ret = of_property_read_u32(pdev->dev.of_node, "dma-channels", pchannels); + if (ret) + dev_err(&pdev->dev, "can't get number of channels\n");
Do we need to log error, I thought the API did that...
quoted hunk ↗ jump to hunk
+ + return ret; +} + static int at_xdmac_probe(struct platform_device *pdev) { struct at_xdmac *atxdmac; - int irq, nr_channels, i, ret; + int irq, ret; void __iomem *base; - u32 reg; + u32 nr_channels, i, reg; irq = platform_get_irq(pdev, 0); if (irq < 0)@@ -2278,7 +2295,10 @@ static int at_xdmac_probe(struct platform_device *pdev) * of channels to do the allocation. */ reg = readl_relaxed(base + AT_XDMAC_GTYPE); - nr_channels = AT_XDMAC_NB_CH(reg); + ret = at_xdmac_get_channel_number(pdev, reg, &nr_channels); + if (ret) + return ret; + if (nr_channels > AT_XDMAC_MAX_CHAN) { dev_err(&pdev->dev, "invalid number of channels (%u)\n", nr_channels);-- 2.52.0
-- ~Vinod