Re: [PATCH V5 3/3] mmc: sdhci: Fix O2 Host data read/write DLL Lock Phase shift issue

From: Adrian Hunter
Date: Thu Aug 08 2019 - 03:37:22 EST

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On 8/08/19 12:10 AM, Shirley Her (SC) wrote:
> Fix data read/write error in HS200 mode due to chip DLL lock phase shift
>
> Signed-off-by:Shirley Her <shirley.her@xxxxxxxxxxxxxx>
> ---
> change in V5:
> 1. split 2 patches into 3 patches
> 2. make dll_adjust_count start from 0
> 3. fix ret overwritten issue
> 4. use break instead of goto
>
> change in V4:
> 1. add a bug fix for V3
>
> change in V3:
> 1. add more explanation in dll_recovery and execute_tuning function
> 2. move dll_adjust_count to O2_host struct
> 3. fix some coding style error
> 4. renaming O2_PLL_WDT_CONTROL1 TO O2_PLL_DLL_WDT_CONTROL1
>
> change in V2:
> 1. use usleep_range instead of udelay
> 2. move dll_adjust_count to sdhci-pci-o2micro.c
>
> chagne in V1:
> 1. add error recovery function to relock DLL with correct phase
> 2. retuning HS200 after DLL locked
> ---
> drivers/mmc/host/sdhci-pci-o2micro.c | 111 ++++++++++++++++++++++++++++++++++-
> 1 file changed, 108 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mmc/host/sdhci-pci-o2micro.c b/drivers/mmc/host/sdhci-pci-o2micro.c
> index c780888..443d2a3 100644
> --- a/drivers/mmc/host/sdhci-pci-o2micro.c
> +++ b/drivers/mmc/host/sdhci-pci-o2micro.c
> @@ -55,9 +55,17 @@
> #define O2_PLL_FORCE_ACTIVE BIT(18)
> #define O2_PLL_LOCK_STATUS BIT(14)
> #define O2_PLL_SOFT_RESET BIT(12)
> +#define O2_DLL_LOCK_STATUS BIT(11)
>
> #define O2_SD_DETECT_SETTING 0x324
>
> +static const u32 dmdn_table[4] = {0x2B1C0000,

The size is not needed here i.e.

static const u32 dmdn_table[] = {0x2B1C0000,

> + 0x2C1A0000, 0x371B0000, 0x35100000};

But please define the constant:

#define DMDN_SZ ARRAY_SIZE(dmdn_table)

> +
> +struct o2_host {
> + u8 dll_adjust_count;
> +};
> +
> static void sdhci_o2_wait_card_detect_stable(struct sdhci_host *host)
> {
> ktime_t timeout;
> @@ -153,6 +161,32 @@ static void o2_pci_set_baseclk(struct sdhci_pci_chip *chip, u32 value)
> O2_SD_PLL_SETTING, scratch_32);
> }
>
> +static int sdhci_o2_wait_dll_detect_lock(struct sdhci_host *host)
> +{
> + ktime_t timeout;
> + u32 scratch32;
> +
> + usleep_range(5000, 6000);
> + scratch32 = sdhci_readl(host, O2_PLL_DLL_WDT_CONTROL1);
> + if (!(scratch32 & O2_DLL_LOCK_STATUS)) {
> + pr_warn("%s: DLL is still unlocked after wait 5ms\n",
> + mmc_hostname(host->mmc));
> + }
> +
> + /* Detect 1 s */
> + timeout = ktime_add_ms(ktime_get(), 1000);
> + while (1) {
> + bool timedout = ktime_after(ktime_get(), timeout);
> +
> + scratch32 = sdhci_readl(host, O2_PLL_DLL_WDT_CONTROL1);
> + if (!(scratch32 & O2_DLL_LOCK_STATUS))
> + return 0;
> +
> + if (timedout)
> + return 1;

There should be a usleep_range here.

> + }
> +}
> +
> static void sdhci_o2_set_tuning_mode(struct sdhci_host *host)
> {
> u16 reg;
> @@ -190,6 +224,66 @@ static void __sdhci_o2_execute_tuning(struct sdhci_host *host, u32 opcode)
> sdhci_reset_tuning(host);
> }
>
> +/* this function is used to fix o2 dll shift issue */
> +static int sdhci_o2_dll_recovery(struct sdhci_host *host)
> +{
> + int ret = 0;
> + u8 scratch_8 = 0;
> + u32 scratch_32 = 0;
> + struct sdhci_pci_slot *slot = sdhci_priv(host);
> + struct sdhci_pci_chip *chip = slot->chip;
> + struct o2_host *o2_host = sdhci_pci_priv(slot);
> +
> + /* Disable clock */
> + sdhci_writeb(host, 0, SDHCI_CLOCK_CONTROL);
> + while (o2_host->dll_adjust_count < 4 && 0 == ret) {

Please use DMDN_SZ here instead of 4

> + /* UnLock WP */
> + pci_read_config_byte(chip->pdev,
> + O2_SD_LOCK_WP, &scratch_8);
> + scratch_8 &= 0x7f;
> + pci_write_config_byte(chip->pdev, O2_SD_LOCK_WP, scratch_8);
> +
> + /* PLL software reset */
> + scratch_32 = sdhci_readl(host, O2_PLL_DLL_WDT_CONTROL1);
> + scratch_32 |= O2_PLL_SOFT_RESET;
> + sdhci_writel(host, scratch_32, O2_PLL_DLL_WDT_CONTROL1);
> +
> + pci_read_config_dword(chip->pdev,
> + O2_SD_FUNC_REG4,
> + &scratch_32);
> + /* Enable Base Clk setting change */
> + scratch_32 |= O2_SD_FREG4_ENABLE_CLK_SET;
> + pci_write_config_dword(chip->pdev, O2_SD_FUNC_REG4, scratch_32);
> + o2_pci_set_baseclk(chip, dmdn_table[o2_host->dll_adjust_count]);
> + o2_host->dll_adjust_count++;
> + /* Enable internal clock */
> + scratch_8 = SDHCI_CLOCK_INT_EN;
> + sdhci_writeb(host, scratch_8, SDHCI_CLOCK_CONTROL);
> +
> + if (sdhci_o2_get_cd(host->mmc)) {
> + if (sdhci_o2_wait_dll_detect_lock(host)) {
> + scratch_8 |= SDHCI_CLOCK_CARD_EN;
> + sdhci_writeb(host, scratch_8,
> + SDHCI_CLOCK_CONTROL);
> + ret = 1;
> + } else {
> + pr_warn("%s: DLL unlocked when dll_adjust_count is %d.\n",
> + mmc_hostname(host->mmc),
> + o2_host->dll_adjust_count);
> + }
> + }

if !sdhci_o2_get_cd(host->mmc) this will loop forever

> + }
> + if (o2_host->dll_adjust_count == 5)

Shouldn't that be:

if (!ret && o2_host->dll_adjust_count == DMDN_SZ)

> + pr_err("%s: DLL adjust over max times\n",
> + mmc_hostname(host->mmc));
> + /* Lock WP */
> + pci_read_config_byte(chip->pdev,
> + O2_SD_LOCK_WP, &scratch_8);
> + scratch_8 |= 0x80;
> + pci_write_config_byte(chip->pdev, O2_SD_LOCK_WP, scratch_8);
> + return ret;
> +}
> +
> static int sdhci_o2_execute_tuning(struct mmc_host *mmc, u32 opcode)
> {
> struct sdhci_host *host = mmc_priv(mmc);
> @@ -204,7 +298,16 @@ static int sdhci_o2_execute_tuning(struct mmc_host *mmc, u32 opcode)
>
> if (WARN_ON(opcode != MMC_SEND_TUNING_BLOCK_HS200))
> return -EINVAL;
> -
> + /*
> + * Judge the tuning reason, whether caused by dll shift
> + * If cause by dll shift, should call sdhci_o2_dll_recovery
> + */
> + if (!sdhci_o2_wait_dll_detect_lock(host))
> + if (!sdhci_o2_dll_recovery(host)) {
> + pr_err("%s: o2 dll recovery failed\n",
> + mmc_hostname(host->mmc));
> + return -EINVAL;
> + }
> /*
> * o2 sdhci host didn't support 8bit emmc tuning
> */
> @@ -371,7 +474,7 @@ static void sdhci_o2_enable_clk(struct sdhci_host *host, u16 clk)
> /* Enable internal clock */
> clk |= SDHCI_CLOCK_INT_EN;
> sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> -

Please leave the blank line. It improves readability.

> + sdhci_o2_enable_internal_clock(host);
> if (sdhci_o2_get_cd(host->mmc)) {
> clk |= SDHCI_CLOCK_CARD_EN;
> sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
> @@ -397,12 +500,13 @@ int sdhci_pci_o2_probe_slot(struct sdhci_pci_slot *slot)
> {
> struct sdhci_pci_chip *chip;
> struct sdhci_host *host;
> + struct o2_host *o2_host = sdhci_pci_priv(slot);
> u32 reg, caps;
> int ret;
>
> chip = slot->chip;
> host = slot->host;
> -

Please leave the blank line. It improves readability.

> + o2_host->dll_adjust_count = 0;
> caps = sdhci_readl(host, SDHCI_CAPABILITIES);
>
> /*
> @@ -689,4 +793,5 @@ const struct sdhci_pci_fixes sdhci_o2 = {
> .resume = sdhci_pci_o2_resume,
> #endif
> .ops = &sdhci_pci_o2_ops,
> + .priv_size = sizeof(struct o2_host),
> };
>

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