Re: [PATCH V8 1/2] scsi: ufs: set the device reference clock setting

From: Sayali Lokhande
Date: Thu Aug 16 2018 - 06:44:39 EST


On 8/13/2018 6:06 PM, Adrian Hunter wrote:
On 09/08/18 12:09, Sayali Lokhande wrote:
From: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>

UFS host supplies the reference clock to UFS device and UFS device
specification allows host to provide one of the 4 frequencies (19.2 MHz,
26 MHz, 38.4 MHz, 52 MHz) for reference clock. Host should set the
device reference clock frequency setting in the device based on what
frequency it is supplying to UFS device.

Signed-off-by: Subhash Jadavani <subhashj@xxxxxxxxxxxxxx>
Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
Signed-off-by: Sayali Lokhande <sayalil@xxxxxxxxxxxxxx>
---
drivers/scsi/ufs/ufs.h | 21 ++++++++++
drivers/scsi/ufs/ufshcd-pltfrm.c | 2 +
drivers/scsi/ufs/ufshcd.c | 89 ++++++++++++++++++++++++++++++++++++++++
drivers/scsi/ufs/ufshcd.h | 2 +
4 files changed, 114 insertions(+)

diff --git a/drivers/scsi/ufs/ufs.h b/drivers/scsi/ufs/ufs.h
index 14e5bf7..c555ac0 100644
--- a/drivers/scsi/ufs/ufs.h
+++ b/drivers/scsi/ufs/ufs.h
@@ -378,6 +378,27 @@ enum query_opcode {
UPIU_QUERY_OPCODE_TOGGLE_FLAG = 0x8,
};
+/* bRefClkFreq attribute values */
+enum ref_clk_freq_hz {
+ REF_CLK_FREQ_19_2_MHZ = 19200000,
+ REF_CLK_FREQ_26_MHZ = 26000000,
+ REF_CLK_FREQ_38_4_MHZ = 38400000,
+ REF_CLK_FREQ_52_MHZ = 52000000,
+};
+
+enum bref_clk_freq {
+ bREF_CLK_FREQ_0, /* 19.2 MHz */
+ bREF_CLK_FREQ_1, /* 26 MHz */
+ bREF_CLK_FREQ_2, /* 38.4 MHz */
+ bREF_CLK_FREQ_3, /* 52 MHz */
+ bREF_CLK_FREQ_INVAL,
+};
+
+struct ufs_ref_clk {
+ enum ref_clk_freq_hz freq_hz;
+ enum bref_clk_freq val;
+};
+
/* Query response result code */
enum {
QUERY_RESULT_SUCCESS = 0x00,
diff --git a/drivers/scsi/ufs/ufshcd-pltfrm.c b/drivers/scsi/ufs/ufshcd-pltfrm.c
index e82bde0..0953563 100644
--- a/drivers/scsi/ufs/ufshcd-pltfrm.c
+++ b/drivers/scsi/ufs/ufshcd-pltfrm.c
@@ -343,6 +343,8 @@ int ufshcd_pltfrm_init(struct platform_device *pdev,
pm_runtime_set_active(&pdev->dev);
pm_runtime_enable(&pdev->dev);
+ ufshcd_parse_dev_ref_clk_freq(hba);
+
ufshcd_init_lanes_per_dir(hba);
err = ufshcd_init(hba, mmio_base, irq);
diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c5b1bf1..0cbdde7 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -6296,6 +6296,89 @@ static void ufshcd_def_desc_sizes(struct ufs_hba *hba)
hba->desc_size.hlth_desc = QUERY_DESC_HEALTH_DEF_SIZE;
}
+static struct ufs_ref_clk ufs_ref_clk_freqs[] = {
+ {REF_CLK_FREQ_19_2_MHZ, bREF_CLK_FREQ_0},
+ {REF_CLK_FREQ_26_MHZ, bREF_CLK_FREQ_1},
+ {REF_CLK_FREQ_38_4_MHZ, bREF_CLK_FREQ_2},
+ {REF_CLK_FREQ_52_MHZ, bREF_CLK_FREQ_3},
+};
+
+static inline enum bref_clk_freq
+ufs_get_bref_clk_for_ref_clk_freq_hz(u32 freq)
+{
+ enum bref_clk_freq val;
+
+ for (val = bREF_CLK_FREQ_0; val <= bREF_CLK_FREQ_3; val++)
+ if (ufs_ref_clk_freqs[val].freq_hz == freq)
+ return val;
+
+ /* if no match found, return invalid*/
+ return bREF_CLK_FREQ_INVAL;
+}
+
+void ufshcd_parse_dev_ref_clk_freq(struct ufs_hba *hba)
+{
+ struct device *dev = hba->dev;
+ struct device_node *np = dev->of_node;
+ struct clk *refclk = NULL;
+ u32 freq = 0;
+
+ if (!np)
+ return;
+
+ hba->dev_ref_clk_freq = bREF_CLK_FREQ_INVAL;
+
+ refclk = of_clk_get_by_name(np, "ref_clk");
What about users that don't use DT?
If there is no DT entry present for ref_clk, we simply set to bREF_CLK_FREQ_INVAL and thus ref clk will not be changed. It will maintain the Manufacturer default value whatever is set by the ufs device vendor.

+ if (!refclk)
+ return;
+
+ freq = clk_get_rate(refclk);
+ if (freq > REF_CLK_FREQ_52_MHZ) {
+ dev_err(hba->dev,
+ "%s: invalid ref_clk setting = %d\n",
+ __func__, freq);
+ return;
+ }
+
+ hba->dev_ref_clk_freq =
+ ufs_get_bref_clk_for_ref_clk_freq_hz(freq);
+}
+
+static int ufshcd_set_dev_ref_clk(struct ufs_hba *hba)
+{
+ int err = 0;
+ int ref_clk = -1;
+
+ err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_READ_ATTR,
+ QUERY_ATTR_IDN_REF_CLK_FREQ, 0, 0, &ref_clk);
+
+ if (err) {
+ dev_err(hba->dev, "%s: failed reading bRefClkFreq. err = %d\n",
+ __func__, err);
+ goto out;
+ }
+
+ if (ref_clk == hba->dev_ref_clk_freq)
+ goto out; /* nothing to update */
+
+ err = ufshcd_query_attr_retry(hba, UPIU_QUERY_OPCODE_WRITE_ATTR,
+ QUERY_ATTR_IDN_REF_CLK_FREQ, 0, 0,
+ &hba->dev_ref_clk_freq);
+
+ if (err)
+ dev_err(hba->dev, "%s: bRefClkFreq setting to %d Hz failed\n",
+ __func__, ufs_ref_clk_freqs[hba->dev_ref_clk_freq].freq_hz);
+ /*
+ * It is good to print this out here to debug any later failures
+ * related to gear switch.
+ */
+ dev_dbg(hba->dev, "%s: bRefClkFreq setting to %d Hz succeeded\n",
+ __func__, ufs_ref_clk_freqs[hba->dev_ref_clk_freq].freq_hz);
+
+out:
+ return err;
+}
+
/**
* ufshcd_probe_hba - probe hba to detect device and initialize
* @hba: per-adapter instance
@@ -6361,6 +6444,12 @@ static int ufshcd_probe_hba(struct ufs_hba *hba)
"%s: Failed getting max supported power mode\n",
__func__);
} else {
+ /*
+ * Set the right value to bRefClkFreq before attempting to
+ * switch to HS gears.
+ */
+ if (hba->dev_ref_clk_freq < bREF_CLK_FREQ_INVAL)
hba->dev_ref_clk_freq does not always get initialized
In ufshcd_parse_dev_ref_clk_freq() function we are initializing the hba->dev_ref_clk_freqto inval as default. This parse function will be always called in init and thus dev_ref_clk_freq should always get initialized to defult inval or valid setting if found (in between 19.2 MHz to 52MHz).

+ ufshcd_set_dev_ref_clk(hba);
ret = ufshcd_config_pwr_mode(hba, &hba->max_pwr_info.info);
if (ret) {
dev_err(hba->dev, "%s: Failed setting power mode, err = %d\n",
diff --git a/drivers/scsi/ufs/ufshcd.h b/drivers/scsi/ufs/ufshcd.h
index 8110dcd..101a75c 100644
--- a/drivers/scsi/ufs/ufshcd.h
+++ b/drivers/scsi/ufs/ufshcd.h
@@ -548,6 +548,7 @@ struct ufs_hba {
void *priv;
unsigned int irq;
bool is_irq_enabled;
+ u32 dev_ref_clk_freq;
/* Interrupt aggregation support is broken */
#define UFSHCD_QUIRK_BROKEN_INTR_AGGR 0x1
@@ -746,6 +747,7 @@ static inline void ufshcd_rmwl(struct ufs_hba *hba, u32 mask, u32 val, u32 reg)
int ufshcd_wait_for_register(struct ufs_hba *hba, u32 reg, u32 mask,
u32 val, unsigned long interval_us,
unsigned long timeout_ms, bool can_sleep);
+void ufshcd_parse_dev_ref_clk_freq(struct ufs_hba *hba);
static inline void check_upiu_size(void)
{