linux-kernel - Re: [RFC PATCH v5 1/9] mmc: dw_mmc: Add external dma interface support

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Message-ID: <1522710.BT6Gc0L6oH@diego>
Date:	Sat, 15 Aug 2015 00:13:49 +0200
From:	Heiko Stübner <heiko@...ech.de>
To:	Shawn Lin <shawn.lin@...k-chips.com>
Cc:	jh80.chung@...sung.com, ulf.hansson@...aro.org,
	Vineet.Gupta1@...opsys.com, Wei Xu <xuwei5@...ilicon.com>,
	Joachim Eastwood <manabian@...il.com>,
	Alexey Brodkin <abrodkin@...opsys.com>,
	Kukjin Kim <kgene@...nel.org>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Russell King <linux@....linux.org.uk>,
	Zhangfei Gao <zhangfei.gao@...aro.org>,
	Jun Nie <jun.nie@...aro.org>,
	Ralf Baechle <ralf@...ux-mips.org>,
	Govindraj Raja <govindraj.raja@...tec.com>,
	Arnd Bergmann <arnd@...db.de>, dianders@...omium.org,
	linux-samsung-soc@...r.kernel.org, linux-mips@...ux-mips.org,
	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-rockchip@...ts.infradead.org, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [RFC PATCH v5 1/9] mmc: dw_mmc: Add external dma interface support

Hi Shawn,

Am Freitag, 14. August 2015, 16:34:35 schrieb Shawn Lin:
> DesignWare MMC Controller can supports two types of DMA
> mode: external dma and internal dma. We get a RK312x platform
> integrated dw_mmc and ARM pl330 dma controller. This patch add
> edmac ops to support these platforms. I've tested it on RK312x
> platform with edmac mode and RK3288 platform with idmac mode.
> 
> Signed-off-by: Shawn Lin <shawn.lin@...k-chips.com>

judging by your "from", I guess you're running this on some older Rockchip soc 
without the idma? Because I tried testing this on a Radxa Rock, but only got 
failures, from the start (failed to read card status register). In PIO mode 
everything works again.


I guess I overlooked just some tiny detail, but to me the dma channel ids seem 
correct after all. Maybe you have any hints what I'm doing wrong?

diff --git a/arch/arm/boot/dts/rk3xxx.dtsi b/arch/arm/boot/dts/rk3xxx.dtsi
index 4497d28..92d7156 100644
--- a/arch/arm/boot/dts/rk3xxx.dtsi
+++ b/arch/arm/boot/dts/rk3xxx.dtsi
@@ -217,6 +217,8 @@
                interrupts = <GIC_SPI 23 IRQ_TYPE_LEVEL_HIGH>;
                clocks = <&cru HCLK_SDMMC>, <&cru SCLK_SDMMC>;
                clock-names = "biu", "ciu";
+             dmas = <&dmac2 1>;
+             dma-names = "rx-tx";
                fifo-depth = <256>;
                status = "disabled";
        };
@@ -227,6 +229,8 @@
                interrupts = <GIC_SPI 24 IRQ_TYPE_LEVEL_HIGH>;
                clocks = <&cru HCLK_SDIO>, <&cru SCLK_SDIO>;
                clock-names = "biu", "ciu";
+             dmas = <&dmac2 3>;
+             dma-names = "rx-tx";
                fifo-depth = <256>;
                status = "disabled";
        };
@@ -237,6 +241,8 @@
                interrupts = <GIC_SPI 25 IRQ_TYPE_LEVEL_HIGH>;
                clocks = <&cru HCLK_EMMC>, <&cru SCLK_EMMC>;
                clock-names = "biu", "ciu";
+             dmas = <&dmac2 4>;
+             dma-names = "rx-tx";
                fifo-depth = <256>;
                status = "disabled";
        };


[...]

> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index fcbf552..e01ead3 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -2517,8 +2642,23 @@ static void dw_mci_cleanup_slot(struct dw_mci_slot
> *slot, unsigned int id) static void dw_mci_init_dma(struct dw_mci *host)
>  {
>  	int addr_config;
> +	int trans_mode;
> +	struct device *dev = host->dev;
> +	struct device_node *np = dev->of_node;
> +
> +	/* Check tansfer mode */
> +	trans_mode = SDMMC_GET_TRANS_MODE(mci_readl(host, HCON));
> +	if (trans_mode == 0) {
> +		trans_mode = TRANS_MODE_IDMAC;
> +	} else if (trans_mode == 1 || trans_mode == 2) {
> +		trans_mode = TRANS_MODE_EDMAC;
> +	} else {
> +		trans_mode = TRANS_MODE_PIO;
> +		goto no_dma;
> +	}
> +
>  	/* Check ADDR_CONFIG bit in HCON to find IDMAC address bus width */
> -	addr_config = (mci_readl(host, HCON) >> 27) & 0x01;
> +	addr_config = SDMMC_GET_ADDR_CONFIG(mci_readl(host, HCON));
> 
>  	if (addr_config == 1) {
>  		/* host supports IDMAC in 64-bit address mode */

I guess the idmac address size checking block

        /* Check ADDR_CONFIG bit in HCON to find IDMAC address bus width */
        addr_config = SDMMC_GET_ADDR_CONFIG(mci_readl(host, HCON));

        if (addr_config == 1) {
                /* host supports IDMAC in 64-bit address mode */
                host->dma_64bit_address = 1;
                dev_info(host->dev, "IDMAC supports 64-bit address mode.\n");
                if (!dma_set_mask(host->dev, DMA_BIT_MASK(64)))
                        dma_set_coherent_mask(host->dev, DMA_BIT_MASK(64));
        } else {
                /* host supports IDMAC in 32-bit address mode */
                host->dma_64bit_address = 0;
                dev_info(host->dev, "IDMAC supports 32-bit address mode.\n");
        }

could either live inside the trans_mode == 0 conditional above or get its own
if (trans_mode == 0) conditional. Either way I guess it should not talk about 
idmac when either pio or extdmac are used.


Thanks
Heiko
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