Re: [PATCH V7 2/2] mmc: tegra: HW Command Queue Support for Tegra SDMMC

Thierry Reding
2019-01-10T15:12:00Z

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On Wed, Jan 02, 2019 at 11:36:48AM -0800, Sowjanya Komatineni wrote:
> This patch adds HW Command Queue for supported Tegra SDMMC
> controllers.
>
> As per SD Host 4.20 Spec for Host Control 1 Register, DMA Select
> options supported are
>
> With Host Version 4 Enable = 0,
> b'00:SDMA, b'10:32-bit ADMA2, b'11:64-bit ADMA2
>
> With Host Version 4 Enable = 1,
> b'00:SDMA, b'10:ADMA2, b'11:ADMA3
> Support for 32-bit or 64-bit system addressing of DMAs is selected
> thru 64-bit Addressing in Host Control 2 register.
>
> ADMA3 performs integrated descriptor and each command descriptor
> is followed by ADMA2 descriptor. Command queuing need to fetch
> command and transfer descriptors so need ADMA3 DMA Type.
>
> Tegra SDMMC Host design prevents write access to BLOCK_COUNT
> registers when CQE is enabled to prevent SW from updating block
> size during Command Queue mode so need tegra specific sdhci
> cqe callback.
>
> Signed-off-by: Sowjanya Komatineni <skomatineni@nvidia.com>
> ---
> drivers/mmc/host/Kconfig | 1 +
> drivers/mmc/host/sdhci-tegra.c | 107 ++++++++++++++++++++++++++++++++++++++++-
> drivers/mmc/host/sdhci.c | 16 ++++--
> drivers/mmc/host/sdhci.h | 1 +
> 4 files changed, 120 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/host/Kconfig b/drivers/mmc/host/Kconfig
> index 1b58739d9744..5aa2de2c7609 100644
> --- a/drivers/mmc/host/Kconfig
> +++ b/drivers/mmc/host/Kconfig
> @@ -250,6 +250,7 @@ config MMC_SDHCI_TEGRA
> depends on ARCH_TEGRA
> depends on MMC_SDHCI_PLTFM
> select MMC_SDHCI_IO_ACCESSORS
> + select MMC_CQHCI
> help
> This selects the Tegra SD/MMC controller. If you have a Tegra
> platform with SD or MMC devices, say Y or M here.
> diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
> index 7b95d088fdef..7beecd1da94a 100644
> --- a/drivers/mmc/host/sdhci-tegra.c
> +++ b/drivers/mmc/host/sdhci-tegra.c
> @@ -33,6 +33,7 @@
> #include <linux/ktime.h>
>
> #include "sdhci-pltfm.h"
> +#include "cqhci.h"
>
> /* Tegra SDHOST controller vendor register definitions */
> #define SDHCI_TEGRA_VENDOR_CLOCK_CTRL 0x100
> @@ -89,6 +90,9 @@
> #define NVQUIRK_NEEDS_PAD_CONTROL BIT(7)
> #define NVQUIRK_DIS_CARD_CLK_CONFIG_TAP BIT(8)
>
> +/* SDMMC CQE Base Address for Tegra Host Ver 4.1 and Higher */
> +#define SDHCI_TEGRA_CQE_BASE_ADDR 0xF000
> +
> struct sdhci_tegra_soc_data {
> const struct sdhci_pltfm_data *pdata;
> u32 nvquirks;
> @@ -128,6 +132,7 @@ struct sdhci_tegra {
> u32 default_tap;
> u32 default_trim;
> u32 dqs_trim;
> + bool enable_hwcq;
> };
>
> static u16 tegra_sdhci_readw(struct sdhci_host *host, int reg)
> @@ -836,6 +841,49 @@ static void tegra_sdhci_voltage_switch(struct sdhci_host *host)
> tegra_host->pad_calib_required = true;
> }
>
> +static void sdhci_tegra_cqe_enable(struct mmc_host *mmc)
> +{
> + struct cqhci_host *cq_host = mmc->cqe_private;
> + u32 cqcfg = 0;
> +
> + /* Tegra SDMMC Controller design prevents write access to BLOCK_COUNT
> + * registers when CQE is enabled.
> + */

Block comments usually have the opening /* on a line by itself.

> + cqcfg = cqhci_readl(cq_host, CQHCI_CFG);
> + if (cqcfg & CQHCI_ENABLE)
> + cqhci_writel(cq_host, (cqcfg & ~CQHCI_ENABLE), CQHCI_CFG);
> +
> + sdhci_cqe_enable(mmc);
> +
> + if (cqcfg & CQHCI_ENABLE)
> + cqhci_writel(cq_host, cqcfg, CQHCI_CFG);
> +
> +}

Extra blank line above.

> +
> +static void sdhci_tegra_dumpregs(struct mmc_host *mmc)
> +{
> + sdhci_dumpregs(mmc_priv(mmc));
> +}
> +
> +static u32 sdhci_tegra_cqhci_irq(struct sdhci_host *host, u32 intmask)
> +{
> + int cmd_error = 0;
> + int data_error = 0;
> +
> + if (!sdhci_cqe_irq(host, intmask, &cmd_error, &data_error))
> + return intmask;
> +
> + cqhci_irq(host->mmc, intmask, cmd_error, data_error);
> +
> + return 0;
> +}
> +
> +static const struct cqhci_host_ops sdhci_tegra_cqhci_ops = {
> + .enable = sdhci_tegra_cqe_enable,
> + .disable = sdhci_cqe_disable,
> + .dumpregs = sdhci_tegra_dumpregs,
> +};
> +
> static const struct sdhci_ops tegra_sdhci_ops = {
> .get_ro = tegra_sdhci_get_ro,
> .read_w = tegra_sdhci_readw,
> @@ -989,6 +1037,7 @@ static const struct sdhci_ops tegra186_sdhci_ops = {
> .set_uhs_signaling = tegra_sdhci_set_uhs_signaling,
> .voltage_switch = tegra_sdhci_voltage_switch,
> .get_max_clock = tegra_sdhci_get_max_clock,
> + .irq = sdhci_tegra_cqhci_irq,
> };
>
> static const struct sdhci_pltfm_data sdhci_tegra186_pdata = {
> @@ -1030,6 +1079,55 @@ static const struct of_device_id sdhci_tegra_dt_match[] = {
> };
> MODULE_DEVICE_TABLE(of, sdhci_tegra_dt_match);
>
> +static int sdhci_tegra_add_host(struct sdhci_host *host)
> +{
> + struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_tegra *tegra_host = sdhci_pltfm_priv(pltfm_host);
> + struct cqhci_host *cq_host;
> + bool dma64;
> + int ret;
> +
> + if (!tegra_host->enable_hwcq)
> + return sdhci_add_host(host);
> +
> + host->v4_mode = true;
> +
> + ret = sdhci_setup_host(host);
> + if (ret)
> + return ret;
> +
> + host->mmc->caps2 |= MMC_CAP2_CQE | MMC_CAP2_CQE_DCMD;
> +
> + cq_host = devm_kzalloc(host->mmc->parent,
> + sizeof(*cq_host), GFP_KERNEL);
> + if (!cq_host) {
> + ret = -ENOMEM;
> + goto cleanup;
> + }
> +
> + cq_host->mmio = host->ioaddr + SDHCI_TEGRA_CQE_BASE_ADDR;
> + cq_host->ops = &sdhci_tegra_cqhci_ops;
> +
> + dma64 = host->flags & SDHCI_USE_64_BIT_DMA;
> + if (dma64)
> + cq_host->caps |= CQHCI_TASK_DESC_SZ_128;
> +
> + ret = cqhci_init(cq_host, host->mmc, dma64);
> + if (ret)
> + goto cleanup;
> +
> + ret = __sdhci_add_host(host);
> + if (ret)
> + goto cleanup;
> +
> + return 0;
> +
> +cleanup:
> + sdhci_cleanup_host(host);
> + return ret;
> +
> +}

Gratuituous blank line above.

> +
> static int sdhci_tegra_probe(struct platform_device *pdev)
> {
> const struct of_device_id *match;
> @@ -1039,6 +1137,7 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
> struct sdhci_tegra *tegra_host;
> struct clk *clk;
> int rc;
> + struct resource *iomem;
>
> match = of_match_device(sdhci_tegra_dt_match, &pdev->dev);
> if (!match)
> @@ -1056,6 +1155,12 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
> tegra_host->pad_control_available = false;
> tegra_host->soc_data = soc_data;
>
> + iomem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (resource_size(iomem) > SDHCI_TEGRA_CQE_BASE_ADDR)
> + tegra_host->enable_hwcq = true;
> + else
> + tegra_host->enable_hwcq = false;
> +
> if (soc_data->nvquirks & NVQUIRK_NEEDS_PAD_CONTROL) {
> rc = tegra_sdhci_init_pinctrl_info(&pdev->dev, tegra_host);
> if (rc == 0)
> @@ -1117,7 +1222,7 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
>
> usleep_range(2000, 4000);
>
> - rc = sdhci_add_host(host);
> + rc = sdhci_tegra_add_host(host);
> if (rc)
> goto err_add_host;
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index fde984d10619..c368230c364d 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -3308,10 +3308,18 @@ void sdhci_cqe_enable(struct mmc_host *mmc)
>
> ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
> ctrl &= ~SDHCI_CTRL_DMA_MASK;
> - if (host->flags & SDHCI_USE_64_BIT_DMA)
> - ctrl |= SDHCI_CTRL_ADMA64;
> - else
> - ctrl |= SDHCI_CTRL_ADMA32;
> + /* As per SD Host 4.20 Spec, Host with V4 Mode enable supports ADMA3
> + * DMA type. ADMA3 performs integrated descriptor which is needed for
> + * cmd queuing as it need to fetch both cmd and transfer descriptors.
> + */

Correct block comment style, please.

Thanks,
Thierry

> + if (host->v4_mode) {
> + ctrl |= SDHCI_CTRL_ADMA3;
> + } else {
> + if (host->flags & SDHCI_USE_64_BIT_DMA)
> + ctrl |= SDHCI_CTRL_ADMA64;
> + else
> + ctrl |= SDHCI_CTRL_ADMA32;
> + }
> sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
>
> sdhci_writew(host, SDHCI_MAKE_BLKSZ(host->sdma_boundary, 512),
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index b001cf4d3d7e..6e2a08f92645 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -88,6 +88,7 @@
> #define SDHCI_CTRL_ADMA1 0x08
> #define SDHCI_CTRL_ADMA32 0x10
> #define SDHCI_CTRL_ADMA64 0x18
> +#define SDHCI_CTRL_ADMA3 0x18
> #define SDHCI_CTRL_8BITBUS 0x20
> #define SDHCI_CTRL_CDTEST_INS 0x40
> #define SDHCI_CTRL_CDTEST_EN 0x80
> --
> 2.7.4
>

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