On 27/03/17 10:49, Yangbo Lu wrote:
> eSDHC could select peripheral clock or platform clock as clock source by
> the PCS bit of eSDHC Control Register, and this bit couldn't be reset by
> software reset for all. In default, the platform clock is used. But we have
> to use peripheral clock since it has a higher frequency to support eMMC
> HS200 mode and SD UHS-I mode. This patch is to add peripheral clock support
> and use it instead of platform clock if it's declared in eSDHC dts node.
>
> Signed-off-by: Yangbo Lu <yangbo.lu@xxxxxxx>
Apart from minor comments:
Acked-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> ---
> Changes for v2:
> - None
> Changes for v3:
> - None
> ---
> drivers/mmc/host/sdhci-esdhc.h | 1 +
> drivers/mmc/host/sdhci-of-esdhc.c | 70 +++++++++++++++++++++++++++++++++++++--
> 2 files changed, 69 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-esdhc.h b/drivers/mmc/host/sdhci-esdhc.h
> index ece8b37..5343fc0 100644
> --- a/drivers/mmc/host/sdhci-esdhc.h
> +++ b/drivers/mmc/host/sdhci-esdhc.h
> @@ -54,6 +54,7 @@
>
> /* Control Register for DMA transfer */
> #define ESDHC_DMA_SYSCTL 0x40c
> +#define ESDHC_PERIPHERAL_CLK_SEL 0x00080000
> #define ESDHC_DMA_SNOOP 0x00000040
>
> #endif /* _DRIVERS_MMC_SDHCI_ESDHC_H */
> diff --git a/drivers/mmc/host/sdhci-of-esdhc.c b/drivers/mmc/host/sdhci-of-esdhc.c
> index ff37e74..7ce1caf 100644
> --- a/drivers/mmc/host/sdhci-of-esdhc.c
> +++ b/drivers/mmc/host/sdhci-of-esdhc.c
> @@ -19,6 +19,7 @@
> #include <linux/delay.h>
> #include <linux/module.h>
> #include <linux/sys_soc.h>
> +#include <linux/clk.h>
> #include <linux/mmc/host.h>
> #include "sdhci-pltfm.h"
> #include "sdhci-esdhc.h"
> @@ -30,6 +31,7 @@ struct sdhci_esdhc {
> u8 vendor_ver;
> u8 spec_ver;
> bool quirk_incorrect_hostver;
> + unsigned int peripheral_clock;
> };
>
> /**
> @@ -414,15 +416,25 @@ static int esdhc_of_enable_dma(struct sdhci_host *host)
> static unsigned int esdhc_of_get_max_clock(struct sdhci_host *host)
> {
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_esdhc *esdhc = sdhci_pltfm_priv(pltfm_host);
>
> - return pltfm_host->clock;
> + if (esdhc->peripheral_clock)
> + return esdhc->peripheral_clock;
> + else
> + return pltfm_host->clock;
> }
>
> static unsigned int esdhc_of_get_min_clock(struct sdhci_host *host)
> {
> struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> + struct sdhci_esdhc *esdhc = sdhci_pltfm_priv(pltfm_host);
> + unsigned int clock;
>
> - return pltfm_host->clock / 256 / 16;
> + if (esdhc->peripheral_clock)
> + clock = esdhc->peripheral_clock;
> + else
> + clock = pltfm_host->clock;
> + return clock / 256 / 16;
> }
>
> static void esdhc_of_set_clock(struct sdhci_host *host, unsigned int clock)
> @@ -512,6 +524,33 @@ static void esdhc_pltfm_set_bus_width(struct sdhci_host *host, int width)
> sdhci_writel(host, ctrl, ESDHC_PROCTL);
> }
>
> +static void esdhc_clock_enable(struct sdhci_host *host, bool enable)
> +{
> + u32 val;
> + u32 timeout;
> +
> + val = sdhci_readl(host, ESDHC_SYSTEM_CONTROL);
> +
> + if (enable)
> + val |= ESDHC_CLOCK_SDCLKEN;
> + else
> + val &= ~ESDHC_CLOCK_SDCLKEN;
> +
> + sdhci_writel(host, val, ESDHC_SYSTEM_CONTROL);
> +
> + timeout = 20;
> + val = ESDHC_CLOCK_STABLE;
> + while (!(sdhci_readl(host, ESDHC_PRSSTAT) & val)) {
> + if (timeout == 0) {
> + pr_err("%s: Internal clock never stabilised.\n",
> + mmc_hostname(host->mmc));
> + break;
> + }
> + timeout--;
> + mdelay(1);
If the time to stabilize is much less that 1 ms then this loop can waste
time. Have a look at the change in sdhci.c.
> + }
> +}
> +
> static void esdhc_reset(struct sdhci_host *host, u8 mask)
> {
> sdhci_reset(host, mask);
> @@ -613,6 +652,9 @@ static void esdhc_init(struct platform_device *pdev, struct sdhci_host *host)
> {
> struct sdhci_pltfm_host *pltfm_host;
> struct sdhci_esdhc *esdhc;
> + struct device_node *np;
> + struct clk *clk;
> + u32 val;
> u16 host_ver;
>
> pltfm_host = sdhci_priv(host);
> @@ -626,6 +668,30 @@ static void esdhc_init(struct platform_device *pdev, struct sdhci_host *host)
> esdhc->quirk_incorrect_hostver = true;
> else
> esdhc->quirk_incorrect_hostver = false;
> +
> + np = pdev->dev.of_node;
> + clk = of_clk_get(np, 0);
Should there be a clk_put somewhere?
> + if (!IS_ERR(clk)) {
> + /*
> + * esdhc->peripheral_clock would be assigned with a value
> + * which is eSDHC base clock when use periperal clock.
> + * For ls1046a, the clock value got by common clk API is
> + * peripheral clock while the eSDHC base clock is 1/2
> + * peripheral clock.
> + */
> + if (of_device_is_compatible(np, "fsl,ls1046a-esdhc"))
> + esdhc->peripheral_clock = clk_get_rate(clk) / 2;
> + else
> + esdhc->peripheral_clock = clk_get_rate(clk);
> + }
> +
> + if (esdhc->peripheral_clock) {
> + esdhc_clock_enable(host, false);
> + val = sdhci_readl(host, ESDHC_DMA_SYSCTL);
> + val |= ESDHC_PERIPHERAL_CLK_SEL;
> + sdhci_writel(host, val, ESDHC_DMA_SYSCTL);
> + esdhc_clock_enable(host, true);
> + }
> }
>
> static int sdhci_esdhc_probe(struct platform_device *pdev)
>
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