Re: [PATCH v5 2/3] mmc: sdhci-tegra: Add support to program MC stream ID

[Adrian Hunter]

On 27/09/22 14:13, Prathamesh Shete wrote:
> SMMU clients are supposed to program stream ID from
> their respective address spaces instead of MC override.
> Define NVQUIRK_PROGRAM_STREAMID and use it to program
> SMMU stream ID from the SDMMC client address space.
> 
> Signed-off-by: Aniruddha TVS Rao <anrao@xxxxxxxxxx>
> Signed-off-by: Prathamesh Shete <pshete@xxxxxxxxxx>
> ---
>  drivers/mmc/host/sdhci-tegra.c | 47 ++++++++++++++++++++++++++++++++++
>  1 file changed, 47 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
> index a6c5bbae77b4..46f37cc26dbb 100644
> --- a/drivers/mmc/host/sdhci-tegra.c
> +++ b/drivers/mmc/host/sdhci-tegra.c
> @@ -25,6 +25,9 @@
>  #include <linux/mmc/slot-gpio.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/ktime.h>
> +#ifdef CONFIG_IOMMU_API
> +#include <linux/iommu.h>
> +#endif
>  
>  #include <soc/tegra/common.h>
>  
> @@ -94,6 +97,8 @@
>  #define SDHCI_TEGRA_AUTO_CAL_STATUS			0x1ec
>  #define SDHCI_TEGRA_AUTO_CAL_ACTIVE			BIT(31)
>  
> +#define SDHCI_TEGRA_CIF2AXI_CTRL_0			0x1fc
> +
>  #define NVQUIRK_FORCE_SDHCI_SPEC_200			BIT(0)
>  #define NVQUIRK_ENABLE_BLOCK_GAP_DET			BIT(1)
>  #define NVQUIRK_ENABLE_SDHCI_SPEC_300			BIT(2)
> @@ -121,6 +126,7 @@
>  #define NVQUIRK_HAS_TMCLK				BIT(10)
>  
>  #define NVQUIRK_HAS_ANDROID_GPT_SECTOR			BIT(11)
> +#define NVQUIRK_PROGRAM_STREAMID			BIT(12)
>  
>  /* SDMMC CQE Base Address for Tegra Host Ver 4.1 and Higher */
>  #define SDHCI_TEGRA_CQE_BASE_ADDR			0xF000
> @@ -128,6 +134,8 @@
>  #define SDHCI_TEGRA_CQE_TRNS_MODE	(SDHCI_TRNS_MULTI | \
>  					 SDHCI_TRNS_BLK_CNT_EN | \
>  					 SDHCI_TRNS_DMA)
> +#define SDHCI_TEGRA_STREAMID_MASK			0xff
> +#define SDHCI_TEGRA_WRITE_STREAMID_SHIFT		0x8
>  
>  struct sdhci_tegra_soc_data {
>  	const struct sdhci_pltfm_data *pdata;
> @@ -177,6 +185,9 @@ struct sdhci_tegra {
>  	bool enable_hwcq;
>  	unsigned long curr_clk_rate;
>  	u8 tuned_tap_delay;
> +#ifdef CONFIG_IOMMU_API
> +	u32 streamid;
> +#endif
>  };
>  
>  static u16 tegra_sdhci_readw(struct sdhci_host *host, int reg)
> @@ -1564,6 +1575,7 @@ static const struct sdhci_tegra_soc_data soc_data_tegra234 = {
>  		    NVQUIRK_DIS_CARD_CLK_CONFIG_TAP |
>  		    NVQUIRK_ENABLE_SDR50 |
>  		    NVQUIRK_ENABLE_SDR104 |
> +		    NVQUIRK_PROGRAM_STREAMID |
>  		    NVQUIRK_HAS_TMCLK,
>  	.min_tap_delay = 95,
>  	.max_tap_delay = 111,
> @@ -1636,6 +1648,9 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
>  	struct sdhci_host *host;
>  	struct sdhci_pltfm_host *pltfm_host;
>  	struct sdhci_tegra *tegra_host;
> +#ifdef CONFIG_IOMMU_API
> +	struct iommu_fwspec *fwspec;
> +#endif

Move this below

>  	struct clk *clk;
>  	int rc;
>  
> @@ -1775,6 +1790,25 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
>  	if (rc)
>  		goto err_add_host;
>  
> +	/* Program MC streamID for DMA transfers */
> +#ifdef CONFIG_IOMMU_API
> +	if (soc_data->nvquirks & NVQUIRK_PROGRAM_STREAMID) {

Can put it here

		struct iommu_fwspec *fwspec;


> +		fwspec = dev_iommu_fwspec_get(&pdev->dev);
> +		if (fwspec == NULL) {
> +			dev_warn(mmc_dev(host->mmc),
> +				"iommu fwspec is NULL, continue without stream ID\n");
> +		} else {
> +			tegra_host->streamid = fwspec->ids[0] & 0xffff;
> +			tegra_sdhci_writel(host, (tegra_host->streamid &
> +						SDHCI_TEGRA_STREAMID_MASK) |
> +						((tegra_host->streamid <<
> +						SDHCI_TEGRA_WRITE_STREAMID_SHIFT)
> +						& SDHCI_TEGRA_STREAMID_MASK),
> +						SDHCI_TEGRA_CIF2AXI_CTRL_0);

This is hard to read.  Maybe use GENMASK and FIELD_PREP, or if the bytes
need swapping, one of the byte swapping macros.

Also, isn't this always zero ?

	((tegra_host->streamid << SDHCI_TEGRA_WRITE_STREAMID_SHIFT) & SDHCI_TEGRA_STREAMID_MASK),


> +		}
> +	}
> +#endif
> +
>  	return 0;
>  
>  err_add_host:
> @@ -1861,6 +1895,10 @@ static int sdhci_tegra_suspend(struct device *dev)
>  static int sdhci_tegra_resume(struct device *dev)
>  {
>  	struct sdhci_host *host = dev_get_drvdata(dev);
> +#ifdef CONFIG_IOMMU_API
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);
> +#endif
>  	int ret;
>  
>  	ret = mmc_gpio_set_cd_wake(host->mmc, false);
> @@ -1871,6 +1909,15 @@ static int sdhci_tegra_resume(struct device *dev)
>  	if (ret)
>  		return ret;
>  
> +	/* Re-program MC streamID for DMA transfers */
> +#ifdef CONFIG_IOMMU_API
> +	if (tegra_host->soc_data->nvquirks & NVQUIRK_PROGRAM_STREAMID) {
> +		tegra_sdhci_writel(host, tegra_host->streamid |
> +					(tegra_host->streamid << 8),

This looks like it ought to be the same calculation as above ?

> +					SDHCI_TEGRA_CIF2AXI_CTRL_0);
> +	}
> +#endif
> +
>  	ret = sdhci_resume_host(host);
>  	if (ret)
>  		goto disable_clk;