Re: [PATCH V1 3/3] mmc: sdhci-msm: Use internal voltage control

From: Adrian Hunter
Date: Wed Jul 25 2018 - 10:06:54 EST

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On 20/07/18 13:46, Vijay Viswanath wrote:
> Some sdhci-msm controllers require that voltage switching be done after
> the HW is ready for it. The HW informs its readiness through power irq.
> The voltage switching should happen only then.
>
> Use the quirk for internal voltage switching and then control the
> voltage switching using power irq.
>
> Signed-off-by: Asutosh Das <asutoshd@xxxxxxxxxxxxxx>
> Signed-off-by: Venkat Gopalakrishnan <venkatg@xxxxxxxxxxxxxx>
> Signed-off-by: Veerabhadrarao Badiganti <vbadigan@xxxxxxxxxxxxxx>
> Signed-off-by: Vijay Viswanath <vviswana@xxxxxxxxxxxxxx>
> ---
> drivers/mmc/host/sdhci-msm.c | 220 ++++++++++++++++++++++++++++++++++++++++---
> 1 file changed, 209 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-msm.c b/drivers/mmc/host/sdhci-msm.c
> index a0dc3e1..47732a2 100644
> --- a/drivers/mmc/host/sdhci-msm.c
> +++ b/drivers/mmc/host/sdhci-msm.c
> @@ -43,7 +43,9 @@
> #define CORE_PWRCTL_IO_LOW BIT(2)
> #define CORE_PWRCTL_IO_HIGH BIT(3)
> #define CORE_PWRCTL_BUS_SUCCESS BIT(0)
> +#define CORE_PWRCTL_BUS_FAIL BIT(1)
> #define CORE_PWRCTL_IO_SUCCESS BIT(2)
> +#define CORE_PWRCTL_IO_FAIL BIT(3)
> #define REQ_BUS_OFF BIT(0)
> #define REQ_BUS_ON BIT(1)
> #define REQ_IO_LOW BIT(2)
> @@ -236,6 +238,14 @@ struct sdhci_msm_variant_info {
> const struct sdhci_msm_offset *offset;
> };
>
> +/* Holds voltage regulator information to be used by the driver*/
> +struct sdhci_msm_vreg_info {
> + bool vmmc_load;
> + u32 vmmc_level[2];
> + bool vqmmc_load;
> + u32 vqmmc_level[2];
> +};

Kernel style is not to introduce structures that are only ever wholly
contained within one other structure i.e. the members of struct
sdhci_msm_vreg_info could just be in struct sdhci_msm_host instead.

> +
> struct sdhci_msm_host {
> struct platform_device *pdev;
> void __iomem *core_mem; /* MSM SDCC mapped address */
> @@ -258,6 +268,8 @@ struct sdhci_msm_host {
> bool mci_removed;
> const struct sdhci_msm_variant_ops *var_ops;
> const struct sdhci_msm_offset *offset;
> + struct sdhci_msm_vreg_info vreg_info;
> + bool pltfm_init_done;
> };
>
> static const struct sdhci_msm_offset *sdhci_priv_msm_offset(struct sdhci_host *host)
> @@ -1314,11 +1326,13 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
> {
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> struct sdhci_msm_host *msm_host = sdhci_pltfm_priv(pltfm_host);
> + struct mmc_host *mmc = host->mmc;
> u32 irq_status, irq_ack = 0;
> - int retry = 10;
> + int retry = 10, ret = 0;
> u32 pwr_state = 0, io_level = 0;
> u32 config;
> const struct sdhci_msm_offset *msm_offset = msm_host->offset;
> + struct sdhci_msm_vreg_info vreg_info = msm_host->vreg_info;
>
> irq_status = msm_host_readl(msm_host, host,
> msm_offset->core_pwrctl_status);
> @@ -1351,14 +1365,91 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
>
> /* Handle BUS ON/OFF*/
> if (irq_status & CORE_PWRCTL_BUS_ON) {
> - pwr_state = REQ_BUS_ON;
> - io_level = REQ_IO_HIGH;
> - irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
> + if (!IS_ERR(mmc->supply.vmmc)) {
> + if (vreg_info.vmmc_load)
> + ret = regulator_set_load(mmc->supply.vmmc,
> + vreg_info.vmmc_level[1]);
> + ret |= mmc_regulator_set_ocr(mmc, mmc->supply.vmmc,
> + mmc->ios.vdd);

Or-ing error numbers seems a bit weird. The code is a bit crammed also,
so I suggest adding helper functions. For example consider something like:

static int sdhci_msm_set_vmmc(struct sdhci_msm_host *msm_host,
struct mmc_host *mmc, int level)
{
int load = msm_host->vmmc_level[level];
int ret;

if (IS_ERR(mmc->supply.vmmc))
return 0;

if (msm_host->vmmc_load) {
ret = regulator_set_load(mmc->supply.vmmc, load);
if (ret)
goto out;
}

ret = mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, mmc->ios.vdd);
out:
if (ret)
pr_err("%s: vmmc failed: %d\n", mmc_hostname(mmc), ret);

return ret;
}

> + if (ret)
> + pr_err("%s: vmmc enable failed: %d\n",
> + mmc_hostname(mmc), ret);
> + }
> +
> + if (!IS_ERR(mmc->supply.vqmmc) && !ret) {
> + struct mmc_ios ios;
> +
> + if (vreg_info.vqmmc_load)
> + ret = regulator_set_load(mmc->supply.vqmmc,
> + vreg_info.vqmmc_level[1]);
> + /*
> + * The IO voltage regulator maynot always support
> + * a voltage close to vdd. Set IO voltage based on
> + * capability of the regulator.
> + */
> + if (msm_host->caps_0 & CORE_3_0V_SUPPORT)
> + ios.signal_voltage = MMC_SIGNAL_VOLTAGE_330;
> + else if (msm_host->caps_0 & CORE_1_8V_SUPPORT)
> + ios.signal_voltage = MMC_SIGNAL_VOLTAGE_180;
> + if (msm_host->caps_0 & CORE_VOLT_SUPPORT) {
> + pr_err("%s: %s: setting signal voltage: %d\n",
> + mmc_hostname(mmc), __func__,
> + ios.signal_voltage);

Why pr_err()?

> + ret |= mmc_regulator_set_vqmmc(mmc, &ios);

Again I suggest createing a helper function and not or-ing error numbers.

> + }
> +
> + if (!ret)
> + ret = regulator_enable(mmc->supply.vqmmc);
> + if (ret)
> + pr_err("%s: vqmmc enable failed: %d\n",
> + mmc_hostname(mmc), ret);
> + }
> + if (!ret) {
> + pwr_state = REQ_BUS_ON;
> + io_level = REQ_IO_HIGH;
> + irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
> + } else {
> + pr_err("%s: BUS_ON req failed(%d). irq_status: 0x%08x\n",
> + mmc_hostname(mmc), ret, irq_status);
> + irq_ack |= CORE_PWRCTL_BUS_FAIL;
> + }
> }
> if (irq_status & CORE_PWRCTL_BUS_OFF) {
> - pwr_state = REQ_BUS_OFF;
> - io_level = REQ_IO_LOW;
> - irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
> + /*
> + * During platform initialization, we may get BUS_OFF request
> + * and turn off the supply. EMMC devices expect Power off
> + * notification before being turned off. So wait till platform
> + * initialization is over to actually turn off power.
> + */
> + if (!IS_ERR(mmc->supply.vmmc) && msm_host->pltfm_init_done) {
> + if (vreg_info.vmmc_load)
> + ret = regulator_set_load(mmc->supply.vmmc,
> + vreg_info.vmmc_level[0]);
> + ret |= mmc_regulator_set_ocr(mmc, mmc->supply.vmmc,
> + mmc->ios.vdd);
> + if (ret)
> + pr_err("%s: vmmc disabling failed: %d\n",
> + mmc_hostname(mmc), ret);
> + }

So with the function above, that would be:

if (msm_host->pltfm_init_done)
ret = sdhci_msm_set_vmmc(msm_host, mmc, 0)

> + if (!IS_ERR(mmc->supply.vqmmc) && msm_host->pltfm_init_done &&
> + !ret) {
> + if (vreg_info.vqmmc_load)
> + ret = regulator_set_load(mmc->supply.vqmmc,
> + vreg_info.vqmmc_level[0]);
> + ret |= regulator_disable(mmc->supply.vqmmc);
> + if (ret)
> + pr_err("%s: vqmmc disabling failed: %d\n",
> + mmc_hostname(mmc), ret);
> + }
> + if (!ret) {
> + pwr_state = REQ_BUS_OFF;
> + io_level = REQ_IO_LOW;
> + irq_ack |= CORE_PWRCTL_BUS_SUCCESS;
> + } else {
> + pr_err("%s: BUS_ON req failed(%d). irq_status: 0x%08x\n",
> + mmc_hostname(mmc), ret, irq_status);
> + irq_ack |= CORE_PWRCTL_BUS_FAIL;
> + }
> }
> /* Handle IO LOW/HIGH */
> if (irq_status & CORE_PWRCTL_IO_LOW) {
> @@ -1370,6 +1461,15 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
> irq_ack |= CORE_PWRCTL_IO_SUCCESS;
> }
>
> + if (io_level && !IS_ERR(mmc->supply.vqmmc) && !pwr_state) {
> + ret = mmc_regulator_set_vqmmc(mmc, &mmc->ios);
> + if (ret)
> + pr_err("%s: IO_level setting failed(%d). signal_voltage: %d, vdd: %d irq_status: 0x%08x\n",
> + mmc_hostname(mmc), ret,
> + mmc->ios.signal_voltage, mmc->ios.vdd,
> + irq_status);
> + }
> +
> /*
> * The driver has to acknowledge the interrupt, switch voltages and
> * report back if it succeded or not to this register. The voltage
> @@ -1415,10 +1515,9 @@ static void sdhci_msm_handle_pwr_irq(struct sdhci_host *host, int irq)
> msm_host->curr_pwr_state = pwr_state;
> if (io_level)
> msm_host->curr_io_level = io_level;
> -
> pr_debug("%s: %s: Handled IRQ(%d), irq_status=0x%x, ack=0x%x\n",
> - mmc_hostname(msm_host->mmc), __func__, irq, irq_status,
> - irq_ack);
> + mmc_hostname(msm_host->mmc), __func__,
> + irq, irq_status, irq_ack);

Seem to be some unrelated whitespace changes here.

> }
>
> static irqreturn_t sdhci_msm_pwr_irq(int irq, void *data)
> @@ -1563,6 +1662,13 @@ static void sdhci_msm_writeb(struct sdhci_host *host, u8 val, int reg)
> sdhci_msm_check_power_status(host, req_type);
> }
>
> +static void sdhci_msm_set_power(struct sdhci_host *host, unsigned char mode,
> + unsigned short vdd)
> +{
> + sdhci_set_power_noreg(host, mode, vdd);

Why not just have .set_power = sdhci_set_power_noreg()

> +
> +}
> +
> static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
> {
> struct mmc_host *mmc = msm_host->mmc;
> @@ -1605,6 +1711,91 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
> pr_debug("%s: supported caps: 0x%08x\n", mmc_hostname(mmc), caps);
> }
>
> +static int sdhci_msm_register_vreg(struct sdhci_msm_host *msm_host)
> +{
> + int ret = 0;
> +
> + ret = mmc_regulator_get_supply(msm_host->mmc);
> + if (ret)
> + return ret;
> + if (device_property_read_u32_array(&msm_host->pdev->dev,
> + "vmmc-current-level",
> + msm_host->vreg_info.vmmc_level, 2) >= 0)
> + msm_host->vreg_info.vmmc_load = true;
> + if (device_property_read_u32_array(&msm_host->pdev->dev,
> + "vqmmc-current-level",
> + msm_host->vreg_info.vqmmc_level, 2) >= 0)
> + msm_host->vreg_info.vqmmc_load = true;
> +
> + sdhci_msm_set_regulator_caps(msm_host);
> +
> + return 0;
> +
> +}
> +
> +static int sdhci_msm_start_signal_voltage_switch(struct mmc_host *mmc,
> + struct mmc_ios *ios)
> +{
> + struct sdhci_host *host = mmc_priv(mmc);
> + u16 ctrl;
> +
> + /*
> + * Signal Voltage Switching is only applicable for Host Controllers
> + * v3.00 and above.
> + */
> + if (host->version < SDHCI_SPEC_300)
> + return 0;
> +
> + ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> +
> + switch (ios->signal_voltage) {
> + case MMC_SIGNAL_VOLTAGE_330:
> + if (!(host->flags & SDHCI_SIGNALING_330))
> + return -EINVAL;
> + /* Set 1.8V Signal Enable in the Host Control2 register to 0 */
> + ctrl &= ~SDHCI_CTRL_VDD_180;
> + sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
> +
> + /* 3.3V regulator output should be stable within 5 ms */
> + ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> + if (!(ctrl & SDHCI_CTRL_VDD_180))
> + return 0;
> +
> + pr_warn("%s: 3.3V regulator output did not became stable\n",
> + mmc_hostname(mmc));
> +
> + return -EAGAIN;
> + case MMC_SIGNAL_VOLTAGE_180:
> + if (!(host->flags & SDHCI_SIGNALING_180))
> + return -EINVAL;
> +
> + /*
> + * Enable 1.8V Signal Enable in the Host Control2
> + * register
> + */
> + ctrl |= SDHCI_CTRL_VDD_180;
> + sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
> +
> + /* 1.8V regulator output should be stable within 5 ms */
> + ctrl = sdhci_readw(host, SDHCI_HOST_CONTROL2);
> + if (ctrl & SDHCI_CTRL_VDD_180)
> + return 0;
> +
> + pr_warn("%s: 1.8V regulator output did not became stable\n",
> + mmc_hostname(mmc));
> +
> + return -EAGAIN;
> + case MMC_SIGNAL_VOLTAGE_120:
> + if (!(host->flags & SDHCI_SIGNALING_120))
> + return -EINVAL;
> + return 0;
> + default:
> + /* No signal voltage switch required */
> + return 0;
> + }
> +
> +}
> +
> static const struct sdhci_msm_variant_ops mci_var_ops = {
> .msm_readl_relaxed = sdhci_msm_mci_variant_readl_relaxed,
> .msm_writel_relaxed = sdhci_msm_mci_variant_writel_relaxed,
> @@ -1644,6 +1835,7 @@ static void sdhci_msm_set_regulator_caps(struct sdhci_msm_host *msm_host)
> .set_uhs_signaling = sdhci_msm_set_uhs_signaling,
> .write_w = sdhci_msm_writew,
> .write_b = sdhci_msm_writeb,
> + .set_power = sdhci_msm_set_power,
> };
>
> static const struct sdhci_pltfm_data sdhci_msm_pdata = {
> @@ -1672,6 +1864,8 @@ static int sdhci_msm_probe(struct platform_device *pdev)
> if (IS_ERR(host))
> return PTR_ERR(host);
>
> + host->mmc_host_ops.start_signal_voltage_switch =
> + sdhci_msm_start_signal_voltage_switch;

Perhaps put this where the other mmc_host_ops assignment is.

> host->sdma_boundary = 0;
> pltfm_host = sdhci_priv(host);
> msm_host = sdhci_pltfm_priv(pltfm_host);
> @@ -1819,6 +2013,10 @@ static int sdhci_msm_probe(struct platform_device *pdev)
> msm_offset->core_vendor_spec_capabilities0);
> }
>
> + ret = sdhci_msm_register_vreg(msm_host);
> + if (ret == -EPROBE_DEFER)

Why not just:

if (ret)

> + goto clk_disable;
> +
> /*
> * Power on reset state may trigger power irq if previous status of
> * PWRCTL was either BUS_ON or IO_HIGH_V. So before enabling pwr irq
> @@ -1867,7 +2065,7 @@ static int sdhci_msm_probe(struct platform_device *pdev)
> ret = sdhci_add_host(host);
> if (ret)
> goto pm_runtime_disable;
> - sdhci_msm_set_regulator_caps(msm_host);
> + msm_host->pltfm_init_done = true;
>
> pm_runtime_mark_last_busy(&pdev->dev);
> pm_runtime_put_autosuspend(&pdev->dev);
>

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Previous message: David Ahern: "Re: [PATCH RFC/RFT net-next 00/17] net: Convert neighbor tables to per-namespace"
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