linux-kernel - Re: [PATCH] mmc: sdhci-msm: Add support for UHS cards

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Message-ID: <5790B89A.3090605@intel.com>
Date:	Thu, 21 Jul 2016 14:57:14 +0300
From:	Adrian Hunter <adrian.hunter@...el.com>
To:	Georgi Djakov <georgi.djakov@...aro.org>, ulf.hansson@...aro.org
Cc:	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-msm@...r.kernel.org
Subject: Re: [PATCH] mmc: sdhci-msm: Add support for UHS cards

On 24/06/16 18:07, Georgi Djakov wrote:
> Enabling support for ultra high speed mode cards requires some
> voltage switching and interaction with the PMIC via a special
> power IRQ. Add support for this.
> 
> Signed-off-by: Georgi Djakov <georgi.djakov@...aro.org>


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


> ---
>  drivers/mmc/host/sdhci-msm.c |   66 ++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 66 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index 0653fe730150..ac5700233e12 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -32,6 +32,21 @@
>  #define CORE_POWER		0x0
>  #define CORE_SW_RST		BIT(7)
>  
> +#define CORE_PWRCTL_STATUS	0xdc
> +#define CORE_PWRCTL_MASK	0xe0
> +#define CORE_PWRCTL_CLEAR	0xe4
> +#define CORE_PWRCTL_CTL		0xe8
> +#define CORE_PWRCTL_BUS_OFF	BIT(0)
> +#define CORE_PWRCTL_BUS_ON	BIT(1)
> +#define CORE_PWRCTL_IO_LOW	BIT(2)
> +#define CORE_PWRCTL_IO_HIGH	BIT(3)
> +#define CORE_PWRCTL_BUS_SUCCESS BIT(0)
> +#define CORE_PWRCTL_IO_SUCCESS	BIT(2)
> +#define REQ_BUS_OFF		BIT(0)
> +#define REQ_BUS_ON		BIT(1)
> +#define REQ_IO_LOW		BIT(2)
> +#define REQ_IO_HIGH		BIT(3)
> +#define INT_MASK		0xf
>  #define MAX_PHASES		16
>  #define CORE_DLL_LOCK		BIT(7)
>  #define CORE_DLL_EN		BIT(16)
> @@ -56,6 +71,7 @@
>  struct sdhci_msm_host {
>  	struct platform_device *pdev;
>  	void __iomem *core_mem;	/* MSM SDCC mapped address */
> +	int pwr_irq;		/* power irq */
>  	struct clk *clk;	/* main SD/MMC bus clock */
>  	struct clk *pclk;	/* SDHC peripheral bus clock */
>  	struct clk *bus_clk;	/* SDHC bus voter clock */
> @@ -410,6 +426,39 @@ retry:
>  	return rc;
>  }
>  
> +static void sdhci_msm_voltage_switch(struct sdhci_host *host)
> +{
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> +	u32 irq_status, irq_ack = 0;
> +
> +	irq_status = readl_relaxed(msm_host->core_mem + CORE_PWRCTL_STATUS);
> +	irq_status &= INT_MASK;
> +
> +	writel_relaxed(irq_status, msm_host->core_mem + CORE_PWRCTL_CLEAR);
> +
> +	if (irq_status & (CORE_PWRCTL_BUS_ON | CORE_PWRCTL_BUS_OFF))
> +		irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
> +	if (irq_status & (CORE_PWRCTL_IO_LOW | CORE_PWRCTL_IO_HIGH))
> +		irq_ack |= CORE_PWRCTL_IO_SUCCESS;
> +
> +	/*
> +	 * The driver has to acknowledge the interrupt, switch voltages and
> +	 * report back if it succeded or not to this register. The voltage
> +	 * switches are handled by the sdhci core, so just report success.
> +	 */
> +	writel_relaxed(irq_ack, msm_host->core_mem + CORE_PWRCTL_CTL);
> +}
> +
> +static irqreturn_t sdhci_msm_pwr_irq(int irq, void *data)
> +{
> +	struct sdhci_host *host = (struct sdhci_host *)data;
> +
> +	sdhci_msm_voltage_switch(host);
> +
> +	return IRQ_HANDLED;
> +}
> +
>  static const struct of_device_id sdhci_msm_dt_match[] = {
>  	{ .compatible = "qcom,sdhci-msm-v4" },
>  	{},
> @@ -423,6 +472,7 @@ static const struct sdhci_ops sdhci_msm_ops = {
>  	.set_clock = sdhci_set_clock,
>  	.set_bus_width = sdhci_set_bus_width,
>  	.set_uhs_signaling = sdhci_set_uhs_signaling,
> +	.voltage_switch = sdhci_msm_voltage_switch,
>  };
>  
>  static const struct sdhci_pltfm_data sdhci_msm_pdata = {
> @@ -545,6 +595,22 @@ static int sdhci_msm_probe(struct platform_device *pdev)
>  			       CORE_VENDOR_SPEC_CAPABILITIES0);
>  	}
>  
> +	/* Setup IRQ for handling power/voltage tasks with PMIC */
> +	msm_host->pwr_irq = platform_get_irq_byname(pdev, "pwr_irq");
> +	if (msm_host->pwr_irq < 0) {
> +		dev_err(&pdev->dev, "Get pwr_irq failed (%d)\n",
> +			msm_host->pwr_irq);
> +		goto clk_disable;
> +	}
> +
> +	ret = devm_request_threaded_irq(&pdev->dev, msm_host->pwr_irq, NULL,
> +					sdhci_msm_pwr_irq, IRQF_ONESHOT,
> +					dev_name(&pdev->dev), host);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Request IRQ failed (%d)\n", ret);
> +		goto clk_disable;
> +	}
> +
>  	ret = sdhci_add_host(host);
>  	if (ret)
>  		goto clk_disable;
>