linux-kernel - Re: [PATCH v1 2/3] mmc: tegra: Implement HW busy wait timeout based on command busy time

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Message-ID: <ae9f09a9-8f39-8dc0-c1c8-fdf40fcea1f6@intel.com>
Date:   Tue, 17 Mar 2020 11:51:07 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Sowjanya Komatineni <skomatineni@...dia.com>,
        ulf.hansson@...aro.org, baolin.wang@...aro.org,
        kstewart@...uxfoundation.org, tglx@...utronix.de,
        bradleybolen@...il.com, gregkh@...uxfoundation.org,
        thierry.reding@...il.com, jonathanh@...dia.com
Cc:     anrao@...dia.com, linux-tegra@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-mmc@...r.kernel.org
Subject: Re: [PATCH v1 2/3] mmc: tegra: Implement HW busy wait timeout based
 on command busy time

On 10/03/20 2:13 am, Sowjanya Komatineni wrote:
> Tegra host supports HW busy detection and timeouts based on the
> count programmed in SDHCI_TIMEOUT_CONTROL register and max busy
> timeout it supports is 11s in finite busy wait mode.
> 
> Some operations like SLEEP_AWAKE, ERASE and flush cache through
> SWITCH commands take longer than 11s and Tegra host supports
> infinite HW busy wait mode where HW waits forever till the card
> is busy without HW timeout.
> 
> This patch implements Tegra specific set_timeout sdhci_ops to allow
> switching between finite and infinite HW busy detection wait modes
> based on the device command expected operation time.
> 
> Signed-off-by: Sowjanya Komatineni <skomatineni@...dia.com>
> ---
>  drivers/mmc/host/sdhci-tegra.c | 31 +++++++++++++++++++++++++++++++

Acked-by: Adrian Hunter <adrian.hunter@...el.com>

>  1 file changed, 31 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c
> index 403ac44..40a221d 100644
> --- a/drivers/mmc/host/sdhci-tegra.c
> +++ b/drivers/mmc/host/sdhci-tegra.c
> @@ -45,6 +45,7 @@
>  #define SDHCI_TEGRA_CAP_OVERRIDES_DQS_TRIM_SHIFT	8
>  
>  #define SDHCI_TEGRA_VENDOR_MISC_CTRL			0x120
> +#define SDHCI_MISC_CTRL_ERASE_TIMEOUT_LIMIT		BIT(0)
>  #define SDHCI_MISC_CTRL_ENABLE_SDR104			0x8
>  #define SDHCI_MISC_CTRL_ENABLE_SDR50			0x10
>  #define SDHCI_MISC_CTRL_ENABLE_SDHCI_SPEC_300		0x20
> @@ -1227,6 +1228,34 @@ static u32 sdhci_tegra_cqhci_irq(struct sdhci_host *host, u32 intmask)
>  	return 0;
>  }
>  
> +static void tegra_sdhci_set_timeout(struct sdhci_host *host,
> +				    struct mmc_command *cmd)
> +{
> +	u32 val;
> +
> +	/*
> +	 * HW busy detection timeout is based on programmed data timeout
> +	 * counter and maximum supported timeout is 11s which may not be
> +	 * enough for long operations like cache flush, sleep awake, erase.
> +	 *
> +	 * ERASE_TIMEOUT_LIMIT bit of VENDOR_MISC_CTRL register allows
> +	 * host controller to wait for busy state until the card is busy
> +	 * without HW timeout.
> +	 *
> +	 * So, use infinite busy wait mode for operations that may take
> +	 * more than maximum HW busy timeout of 11s otherwise use finite
> +	 * busy wait mode.
> +	 */
> +	val = sdhci_readl(host, SDHCI_TEGRA_VENDOR_MISC_CTRL);
> +	if (cmd && cmd->busy_timeout >= 11 * HZ)
> +		val |= SDHCI_MISC_CTRL_ERASE_TIMEOUT_LIMIT;
> +	else
> +		val &= ~SDHCI_MISC_CTRL_ERASE_TIMEOUT_LIMIT;
> +	sdhci_writel(host, val, SDHCI_TEGRA_VENDOR_MISC_CTRL);
> +
> +	__sdhci_set_timeout(host, cmd);
> +}
> +
>  static const struct cqhci_host_ops sdhci_tegra_cqhci_ops = {
>  	.write_l    = tegra_cqhci_writel,
>  	.enable	= sdhci_tegra_cqe_enable,
> @@ -1366,6 +1395,7 @@ static const struct sdhci_ops tegra210_sdhci_ops = {
>  	.set_uhs_signaling = tegra_sdhci_set_uhs_signaling,
>  	.voltage_switch = tegra_sdhci_voltage_switch,
>  	.get_max_clock = tegra_sdhci_get_max_clock,
> +	.set_timeout = tegra_sdhci_set_timeout,
>  };
>  
>  static const struct sdhci_pltfm_data sdhci_tegra210_pdata = {
> @@ -1403,6 +1433,7 @@ static const struct sdhci_ops tegra186_sdhci_ops = {
>  	.voltage_switch = tegra_sdhci_voltage_switch,
>  	.get_max_clock = tegra_sdhci_get_max_clock,
>  	.irq = sdhci_tegra_cqhci_irq,
> +	.set_timeout = tegra_sdhci_set_timeout,
>  };
>  
>  static const struct sdhci_pltfm_data sdhci_tegra186_pdata = {
>