This is a note to let you know that I've just added the patch titled MIPS: lantiq: dma: reset correct number of channel to the 5.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: mips-lantiq-dma-reset-correct-number-of-channel.patch and it can be found in the queue-5.4 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 84e8c5bf81e3b04bb0695e9e85eb676624ec2d99 Author: Aleksander Jan Bajkowski <olek2@xxxxx> Date: Tue Sep 14 23:20:59 2021 +0200 MIPS: lantiq: dma: reset correct number of channel [ Upstream commit 5ca9ce2ba4d5884cd94d1a856c675ab1242cd242 ] Different SoCs have a different number of channels, e.g .: * amazon-se has 10 channels, * danube+ar9 have 20 channels, * vr9 has 28 channels, * ar10 has 24 channels. We can read the ID register and, depending on the reported number of channels, reset the appropriate number of channels. Signed-off-by: Aleksander Jan Bajkowski <olek2@xxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/arch/mips/lantiq/xway/dma.c b/arch/mips/lantiq/xway/dma.c index 24c6267f78698..e45077aecf83a 100644 --- a/arch/mips/lantiq/xway/dma.c +++ b/arch/mips/lantiq/xway/dma.c @@ -30,6 +30,7 @@ #define LTQ_DMA_PCTRL 0x44 #define LTQ_DMA_IRNEN 0xf4 +#define DMA_ID_CHNR GENMASK(26, 20) /* channel number */ #define DMA_DESCPT BIT(3) /* descriptor complete irq */ #define DMA_TX BIT(8) /* TX channel direction */ #define DMA_CHAN_ON BIT(0) /* channel on / off bit */ @@ -40,7 +41,6 @@ #define DMA_POLL BIT(31) /* turn on channel polling */ #define DMA_CLK_DIV4 BIT(6) /* polling clock divider */ #define DMA_2W_BURST BIT(1) /* 2 word burst length */ -#define DMA_MAX_CHANNEL 20 /* the soc has 20 channels */ #define DMA_ETOP_ENDIANNESS (0xf << 8) /* endianness swap etop channels */ #define DMA_WEIGHT (BIT(17) | BIT(16)) /* default channel wheight */ @@ -206,7 +206,7 @@ ltq_dma_init(struct platform_device *pdev) { struct clk *clk; struct resource *res; - unsigned id; + unsigned int id, nchannels; int i; res = platform_get_resource(pdev, IORESOURCE_MEM, 0); @@ -228,17 +228,18 @@ ltq_dma_init(struct platform_device *pdev) ltq_dma_w32(0, LTQ_DMA_IRNEN); /* reset/configure each channel */ - for (i = 0; i < DMA_MAX_CHANNEL; i++) { + id = ltq_dma_r32(LTQ_DMA_ID); + nchannels = ((id & DMA_ID_CHNR) >> 20); + for (i = 0; i < nchannels; i++) { ltq_dma_w32(i, LTQ_DMA_CS); ltq_dma_w32(DMA_CHAN_RST, LTQ_DMA_CCTRL); ltq_dma_w32(DMA_POLL | DMA_CLK_DIV4, LTQ_DMA_CPOLL); ltq_dma_w32_mask(DMA_CHAN_ON, 0, LTQ_DMA_CCTRL); } - id = ltq_dma_r32(LTQ_DMA_ID); dev_info(&pdev->dev, "Init done - hw rev: %X, ports: %d, channels: %d\n", - id & 0x1f, (id >> 16) & 0xf, id >> 20); + id & 0x1f, (id >> 16) & 0xf, nchannels); return 0; }