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SubjectRe: [PATCH 13/40] mmc: tegra: Poll for calibration completion
On Wed, Aug 01, 2018 at 07:32:03PM +0300, Aapo Vienamo wrote:
> Implement polling with 10 ms timeout for automatic pad drive strength
> calibration.
>
> Signed-off-by: Aapo Vienamo <avienamo@nvidia.com>
> ---
> drivers/mmc/host/sdhci-tegra.c | 21 ++++++++++++++++-----
> 1 file changed, 16 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
> index 7d98455..c8ff267 100644
> --- a/drivers/mmc/host/sdhci-tegra.c
> +++ b/drivers/mmc/host/sdhci-tegra.c
> @@ -16,6 +16,7 @@
> #include <linux/err.h>
> #include <linux/module.h>
> #include <linux/init.h>
> +#include <linux/iopoll.h>
> #include <linux/platform_device.h>
> #include <linux/clk.h>
> #include <linux/io.h>
> @@ -50,6 +51,9 @@
> #define SDHCI_AUTO_CAL_START BIT(31)
> #define SDHCI_AUTO_CAL_ENABLE BIT(29)
>
> +#define SDHCI_TEGRA_AUTO_CAL_STATUS 0x1ec
> +#define SDHCI_TEGRA_AUTO_CAL_ACTIVE BIT(31)
> +
> #define NVQUIRK_FORCE_SDHCI_SPEC_200 BIT(0)
> #define NVQUIRK_ENABLE_BLOCK_GAP_DET BIT(1)
> #define NVQUIRK_ENABLE_SDHCI_SPEC_300 BIT(2)
> @@ -228,13 +232,20 @@ static void tegra_sdhci_reset(struct sdhci_host *host, u8 mask)
>
> static void tegra_sdhci_pad_autocalib(struct sdhci_host *host)
> {
> - u32 val;
> + u32 reg;
> + int ret;
> +
> + reg = sdhci_readl(host, SDHCI_TEGRA_AUTO_CAL_CONFIG);
> + reg |= SDHCI_AUTO_CAL_ENABLE | SDHCI_AUTO_CAL_START;
> + sdhci_writel(host, reg, SDHCI_TEGRA_AUTO_CAL_CONFIG);
>

I know this is preexisting, but I want to make sure we cover this so we
don't run into this down the road: do these bits automatically clear on
calibration completion? Can we run these multiple times and get
everything properly calibrated?

Thierry

> - mdelay(1);
> + /* 10 ms timeout */
> + ret = readl_poll_timeout(host->ioaddr + SDHCI_TEGRA_AUTO_CAL_STATUS,
> + reg, !(reg & SDHCI_TEGRA_AUTO_CAL_ACTIVE),
> + 1, 10000);
>
> - val = sdhci_readl(host, SDHCI_TEGRA_AUTO_CAL_CONFIG);
> - val |= SDHCI_AUTO_CAL_ENABLE | SDHCI_AUTO_CAL_START;
> - sdhci_writel(host,val, SDHCI_TEGRA_AUTO_CAL_CONFIG);
> + if (ret)
> + dev_err(mmc_dev(host->mmc), "Pad autocal timed out\n");
> }
>
> static void tegra_sdhci_set_clock(struct sdhci_host *host, unsigned int clock)
> --
> 2.7.4
>
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