scsi: ufs: Enable WriteBooster on some pre-3.1 UFS devices

The WriteBooster feature can be supported by some pre-3.1 UFS devices by
upgrading firmware.

To enable WriteBooster feature in such devices, introduce a device quirk to
relax the entrance condition of ufshcd_wb_probe() to allow host driver to
check those devices' WriteBooster capability.

WriteBooster feature can be available if below all conditions are
satisfied,

 1. Host enables WriteBooster capability

 2. UFS 3.1 device or UFS pre-3.1 device with quirk
    UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES enabled

 3. The device descriptor shall have DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP
    field

 4. WriteBooster support is specified in above field

Link: https://lore.kernel.org/r/20200508080115.24233-2-stanley.chu@mediatek.com
Reviewed-by: Avri Altman <avri.altman@wdc.com>
Reviewed-by: Asutosh Das <asutoshd@codeaurora.org>
Signed-off-by: Stanley Chu <stanley.chu@mediatek.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

drivers/scsi/ufs/ufs_quirks.h

@@ -101,4 +101,11 @@ struct ufs_dev_fix {
  */
 #define UFS_DEVICE_QUIRK_HOST_VS_DEBUGSAVECONFIGTIME	(1 << 9)
 
+/*
+ * Some pre-3.1 UFS devices can support extended features by upgrading
+ * the firmware. Enable this quirk to make UFS core driver probe and enable
+ * supported features on such devices.
+ */
+#define UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES (1 << 10)
+
 #endif /* UFS_QUIRKS_H_ */

drivers/scsi/ufs/ufshcd.c

@@ -6800,9 +6800,19 @@ out:
 
 static void ufshcd_wb_probe(struct ufs_hba *hba, u8 *desc_buf)
 {
+	if (!ufshcd_is_wb_allowed(hba))
+		return;
+
+	if (hba->desc_size.dev_desc < DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP + 4)
+		goto wb_disabled;
+
 	hba->dev_info.d_ext_ufs_feature_sup =
 		get_unaligned_be32(desc_buf +
 				   DEVICE_DESC_PARAM_EXT_UFS_FEATURE_SUP);
+
+	if (!(hba->dev_info.d_ext_ufs_feature_sup & UFS_DEV_WRITE_BOOSTER_SUP))
+		goto wb_disabled;
+
 	/*
 	 * WB may be supported but not configured while provisioning.
 	 * The spec says, in dedicated wb buffer mode,
@@ -6818,11 +6828,29 @@ static void ufshcd_wb_probe(struct ufs_hba *hba, u8 *desc_buf)
 	hba->dev_info.b_presrv_uspc_en =
 		desc_buf[DEVICE_DESC_PARAM_WB_PRESRV_USRSPC_EN];
 
-	if (!((hba->dev_info.d_ext_ufs_feature_sup &
+	if (!(hba->dev_info.b_wb_buffer_type &&
-		 UFS_DEV_WRITE_BOOSTER_SUP) &&
-		hba->dev_info.b_wb_buffer_type &&
 	      hba->dev_info.d_wb_alloc_units))
-		hba->caps &= ~UFSHCD_CAP_WB_EN;
+		goto wb_disabled;
+
+	return;
+
+wb_disabled:
+	hba->caps &= ~UFSHCD_CAP_WB_EN;
+}
+
+static void ufs_fixup_device_setup(struct ufs_hba *hba)
+{
+	struct ufs_dev_fix *f;
+	struct ufs_dev_info *dev_info = &hba->dev_info;
+
+	for (f = ufs_fixups; f->quirk; f++) {
+		if ((f->wmanufacturerid == dev_info->wmanufacturerid ||
+		     f->wmanufacturerid == UFS_ANY_VENDOR) &&
+		     ((dev_info->model &&
+		       STR_PRFX_EQUAL(f->model, dev_info->model)) ||
+		      !strcmp(f->model, UFS_ANY_MODEL)))
+			hba->dev_quirks |= f->quirk;
+	}
 }
 
 static int ufs_get_device_desc(struct ufs_hba *hba)
@@ -6862,10 +6890,6 @@ static int ufs_get_device_desc(struct ufs_hba *hba)
 
 	model_index = desc_buf[DEVICE_DESC_PARAM_PRDCT_NAME];
 
-	/* Enable WB only for UFS-3.1 */
-	if (dev_info->wspecversion >= 0x310)
-		ufshcd_wb_probe(hba, desc_buf);
-
 	err = ufshcd_read_string_desc(hba, model_index,
 				      &dev_info->model, SD_ASCII_STD);
 	if (err < 0) {
@@ -6874,6 +6898,16 @@ static int ufs_get_device_desc(struct ufs_hba *hba)
 		goto out;
 	}
 
+	ufs_fixup_device_setup(hba);
+
+	/*
+	 * Probe WB only for UFS-3.1 devices or UFS devices with quirk
+	 * UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES enabled
+	 */
+	if (dev_info->wspecversion >= 0x310 ||
+	    (hba->dev_quirks & UFS_DEVICE_QUIRK_SUPPORT_EXTENDED_FEATURES))
+		ufshcd_wb_probe(hba, desc_buf);
+
 	/*
 	 * ufshcd_read_string_desc returns size of the string
 	 * reset the error value
@@ -6893,21 +6927,6 @@ static void ufs_put_device_desc(struct ufs_hba *hba)
 	dev_info->model = NULL;
 }
 
-static void ufs_fixup_device_setup(struct ufs_hba *hba)
-{
-	struct ufs_dev_fix *f;
-	struct ufs_dev_info *dev_info = &hba->dev_info;
-
-	for (f = ufs_fixups; f->quirk; f++) {
-		if ((f->wmanufacturerid == dev_info->wmanufacturerid ||
-		     f->wmanufacturerid == UFS_ANY_VENDOR) &&
-		     ((dev_info->model &&
-		       STR_PRFX_EQUAL(f->model, dev_info->model)) ||
-		      !strcmp(f->model, UFS_ANY_MODEL)))
-			hba->dev_quirks |= f->quirk;
-	}
-}
-
 /**
  * ufshcd_tune_pa_tactivate - Tunes PA_TActivate of local UniPro
  * @hba: per-adapter instance
@@ -7244,8 +7263,6 @@ static int ufshcd_device_params_init(struct ufs_hba *hba)
 
 	ufshcd_get_ref_clk_gating_wait(hba);
 
-	ufs_fixup_device_setup(hba);
-
 	if (!ufshcd_query_flag_retry(hba, UPIU_QUERY_OPCODE_READ_FLAG,
 			QUERY_FLAG_IDN_PWR_ON_WPE, &flag))
 		hba->dev_info.f_power_on_wp_en = flag;