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Subject[PATCH V8 3/3] mmc: sdhci-pci-o2micro: Fix O2 Host data read/write DLL Lock phase shift issue
Date
Fix data read/write error in HS200 mode due to chip DLL lock phase shift

Signed-off-by: Shirley Her <shirley.her@bayhubtech.com>
---
change in V8:
1. fix patch format error

change in V7:
1. change subject
2. change the sdhci_o2_wait_dll_detect_lock_function
3. add suitable usleep_range() to detect dll lock status

change in V6:
1. define constant by using array size
2. add more explanation for the code
3. fix loop forever code error

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 | 124 ++++++++++++++++++++++++++++++++++-
1 file changed, 122 insertions(+), 2 deletions(-)

diff --git a/drivers/mmc/host/sdhci-pci-o2micro.c b/drivers/mmc/host/sdhci-pci-o2micro.c
index 57c8b83..d879d91 100644
--- a/drivers/mmc/host/sdhci-pci-o2micro.c
+++ b/drivers/mmc/host/sdhci-pci-o2micro.c
@@ -11,6 +11,7 @@
#include <linux/mmc/host.h>
#include <linux/mmc/mmc.h>
#include <linux/delay.h>
+#include <linux/iopoll.h>

#include "sdhci.h"
#include "sdhci-pci.h"
@@ -55,9 +56,18 @@
#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[] = {0x2B1C0000,
+ 0x2C1A0000, 0x371B0000, 0x35100000};
+#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;
@@ -133,7 +143,8 @@ static int sdhci_o2_get_cd(struct mmc_host *mmc)
{
struct sdhci_host *host = mmc_priv(mmc);

- sdhci_o2_enable_internal_clock(host);
+ if (!(sdhci_readw(host, O2_PLL_DLL_WDT_CONTROL1) & O2_PLL_LOCK_STATUS))
+ sdhci_o2_enable_internal_clock(host);

return !!(sdhci_readl(host, SDHCI_PRESENT_STATE) & SDHCI_CARD_PRESENT);
}
@@ -152,6 +163,25 @@ static void o2_pci_set_baseclk(struct sdhci_pci_chip *chip, u32 value)
O2_SD_PLL_SETTING, scratch_32);
}

+static u32 sdhci_o2_pll_dll_wdt_control(struct sdhci_host *host)
+{
+ return sdhci_readl(host, O2_PLL_DLL_WDT_CONTROL1);
+}
+
+/*
+ * This function is used to detect dll lock status.
+ * Since the dll lock status bit will toggle randomly
+ * with very short interval which needs to be polled
+ * as fast as possible. Set sleep_us as 1 microsecond.
+ */
+static int sdhci_o2_wait_dll_detect_lock(struct sdhci_host *host)
+{
+ u32 scratch32 = 0;
+
+ return readx_poll_timeout(sdhci_o2_pll_dll_wdt_control, host,
+ scratch32, !(scratch32 & O2_DLL_LOCK_STATUS), 1, 1000000);
+}
+
static void sdhci_o2_set_tuning_mode(struct sdhci_host *host)
{
u16 reg;
@@ -189,6 +219,83 @@ 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.
+ * It isn't necessary to detect card present before recovery.
+ * Firstly, it is used by bht emmc card, which is embedded.
+ * Second, before call recovery card present will be detected
+ * outside of the execute tuning function.
+ */
+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);
+
+ /* 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);
+ while (o2_host->dll_adjust_count < DMDN_SZ && !ret) {
+ /* Disable clock */
+ sdhci_writeb(host, 0, SDHCI_CLOCK_CONTROL);
+
+ /* 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]);
+
+ /* Enable internal clock */
+ scratch_8 = SDHCI_CLOCK_INT_EN;
+ sdhci_writeb(host, scratch_8, SDHCI_CLOCK_CONTROL);
+
+ if (sdhci_o2_get_cd(host->mmc)) {
+ /*
+ * need wait at least 5ms for dll status stable,
+ * after enable internal clock
+ */
+ usleep_range(5000, 6000);
+ 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);
+ }
+ } else {
+ pr_err("%s: card present detect failed.\n",
+ mmc_hostname(host->mmc));
+ break;
+ }
+
+ o2_host->dll_adjust_count++;
+ }
+ 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);
@@ -203,7 +310,16 @@ 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
*/
@@ -371,6 +487,7 @@ static void sdhci_o2_enable_clk(struct sdhci_host *host, u16 clk)
clk |= SDHCI_CLOCK_INT_EN;
sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);

+ 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);
@@ -396,12 +513,14 @@ 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;

+ o2_host->dll_adjust_count = 0;
caps = sdhci_readl(host, SDHCI_CAPABILITIES);

/*
@@ -688,4 +807,5 @@ const struct sdhci_pci_fixes sdhci_o2 = {
.resume = sdhci_pci_o2_resume,
#endif
.ops = &sdhci_pci_o2_ops,
+ .priv_size = sizeof(struct o2_host),
};
--
2.7.4
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