[PATCH v2 07/11] scsi: ufs: ufs-qcom: Fixup PAM-4 TX L0_L1_L2_L3 adaptation pattern length

[Can Guo <can.guo@oss.qualcomm.com>]

If HS-G6 Power Mode change handshake is successful and outbound data Lanes
are expected to transmit ADAPT, M-TX Lanes shall be configured as

if (Adapt Type == REFRESH)
  TX_HS_ADAPT_LENGTH_L0_L1_L2_L3 = PA_PeerRxHsG6AdaptRefreshL0L1L2L3.
else if (Adapt Type == INITIAL)
  TX_HS_ADAPT_LENGTH_L0_L1_L2_L3 = PA_PeerRxHsG6AdaptInitialL0L1L2L3.

On some platforms, the ADAPT_L0_L1_L2_L3 duration on Host TX Lanes is only
a half of theoretical ADAPT_L0_L1_L2_L3 duration TADAPT_L0_L1_L2_L3 (in
PAM-4 UI) calculated from TX_HS_ADAPT_LENGTH_L0_L1_L2_L3.

For such platforms, the workaround is to double the ADAPT_L0_L1_L2_L3
duration by uplifting TX_HS_ADAPT_LENGTH_L0_L1_L2_L3. UniPro initializes
TX_HS_ADAPT_LENGTH_L0_L1_L2_L3 during HS-G6 Power Mode change handshake,
it would be too late for SW to update TX_HS_ADAPT_LENGTH_L0_L1_L2_L3 post
HS-G6 Power Mode change. Update PA_PeerRxHsG6AdaptRefreshL0L1L2L3 and
PA_PeerRxHsG6AdaptInitialL0L1L2L3 post Link Startup and before HS-G6
Power Mode change, so that the UniPro would use the updated value during
HS-G6 Power Mode change handshake.

Signed-off-by: Can Guo <can.guo@oss.qualcomm.com>
---
 drivers/ufs/host/ufs-qcom.c | 175 ++++++++++++++++++++++++++++++++++++
 1 file changed, 175 insertions(+)

diff --git a/drivers/ufs/host/ufs-qcom.c b/drivers/ufs/host/ufs-qcom.c
index 5eb12a999eb1..3a9279066192 100644
--- a/drivers/ufs/host/ufs-qcom.c
+++ b/drivers/ufs/host/ufs-qcom.c
@@ -1079,10 +1079,185 @@ static void ufs_qcom_override_pa_tx_hsg1_sync_len(struct ufs_hba *hba)
 		dev_err(hba->dev, "Failed (%d) set PA_TX_HSG1_SYNC_LENGTH\n", err);
 }
 
+/**
+ * ufs_qcom_double_t_adapt_l0l1l2l3 - Create a new adapt that doubles the
+ * adaptation duration TADAPT_L0_L1_L2_L3 derived from the old adapt.
+ *
+ * @old_adapt: Original ADAPT_L0_L1_L2_L3 capability
+ *
+ * ADAPT_length_L0_L1_L2_L3 formula from M-PHY spec:
+ * if (ADAPT_range_L0_L1_L2_L3 == COARSE) {
+ *   ADAPT_length_L0_L1_L2_L3 = [0, 12]
+ *   ADAPT_L0_L1_L2_L3 = 215 x 2^ADAPT_length_L0_L1_L2_L3
+ * } else if (ADAPT_range_L0_L1_L2_L3 == FINE) {
+ *   ADAPT_length_L0_L1_L2_L3 = [0, 127]
+ *   TADAPT_L0_L1_L2_L3 = 215 x (ADAPT_length_L0_L1_L2_L3 + 1)
+ * }
+ *
+ * To double the adaptation duration TADAPT_L0_L1_L2_L3:
+ * 1. If adapt range is COARSE (1'b1), new adapt = old adapt + 1.
+ * 2. If adapt range is FINE (1'b0):
+ *   a) If old adapt length is < 64, (new adapt + 1) = 2 * (old adapt + 1).
+ *   b) If old adapt length is >= 64, set new adapt to 0x88 using COARSE
+ *      range, because new adapt get from equation in a) shall exceed 127.
+ *
+ * Examples:
+ * ADAPT_range_L0_L1_L2_L3 | ADAPT_length_L0_L1_L2_L3 | TADAPT_L0_L1_L2_L3 (PAM-4 UI)
+ *		0			3			131072
+ *		0			7			262144
+ *		0			63			2097152
+ *		0			64			2129920
+ *		0			127			4194304
+ *		1			8			8388608
+ *		1			9			16777216
+ *		1			10			33554432
+ *		1			11			67108864
+ *		1			12			134217728
+ *
+ * Return: new adapt.
+ */
+static inline u32 ufs_qcom_double_t_adapt_l0l1l2l3(u32 old_adapt)
+{
+	u32 adapt_length = old_adapt & 0x7F;
+	u32 new_adapt;
+
+	/* Adapt range == COARSE */
+	if (old_adapt & 0x80) {
+		new_adapt = (adapt_length + 1) | 0x80;
+	} else {
+		if (adapt_length < 64)
+			new_adapt = (adapt_length << 1) + 1;
+		else
+			new_adapt = 0x88;
+	}
+
+	return new_adapt;
+}
+
+static inline void ufs_qcom_limit_max_gear(struct ufs_hba *hba,
+					   enum ufs_hs_gear_tag gear)
+{
+	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
+	struct ufs_pa_layer_attr *pwr_info = &hba->max_pwr_info.info;
+	struct ufs_host_params *host_params = &host->host_params;
+
+	host_params->hs_tx_gear = gear;
+	host_params->hs_rx_gear = gear;
+	pwr_info->gear_tx = gear;
+	pwr_info->gear_rx = gear;
+
+	dev_warn(hba->dev, "Limited max gear of both sides to HS-G%d\n", gear);
+}
+
+static void ufs_qcom_fixup_tx_adapt_l0l1l2l3(struct ufs_hba *hba)
+{
+	struct ufs_qcom_host *host = ufshcd_get_variant(hba);
+	struct ufs_pa_layer_attr *pwr_info = &hba->max_pwr_info.info;
+	struct ufs_host_params *host_params = &host->host_params;
+	u32 adapt_l0l1l2l3, new_adapt, actual_adapt;
+	bool limit_speed = false;
+	int err;
+
+	if (host->hw_ver.major != 0x7 || host->hw_ver.minor > 0x1 ||
+	    host_params->hs_tx_gear <= UFS_HS_G5 ||
+	    pwr_info->gear_tx <= UFS_HS_G5)
+		return;
+
+	err = ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTINITIALL0L1L2L3), &adapt_l0l1l2l3);
+	if (err)
+		goto out;
+
+	if (adapt_l0l1l2l3 > ADAPT_L0L1L2L3_LENGTH_MAX) {
+		dev_err(hba->dev, "PA_PeerRxHsG6AdaptInitialL0L1L2L3 value (0x%x) exceeds MAX.\n",
+			adapt_l0l1l2l3);
+		err = -EINVAL;
+		goto out;
+	}
+
+	new_adapt = ufs_qcom_double_t_adapt_l0l1l2l3(adapt_l0l1l2l3);
+	dev_dbg(hba->dev, "Original PA_PeerRxHsG6AdaptInitialL0L1L2L3 value = 0x%x, new value = 0x%x\n",
+		adapt_l0l1l2l3, new_adapt);
+
+	/*
+	 * 0x8C is the max possible value allowed by UniPro v3.0 spec, some HWs
+	 * can accept 0x8D but some cannot.
+	 */
+	if (new_adapt <= ADAPT_L0L1L2L3_LENGTH_MAX ||
+	    (new_adapt == ADAPT_L0L1L2L3_LENGTH_MAX + 1 && host->hw_ver.minor == 0x1)) {
+		err = ufshcd_dme_set(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTINITIALL0L1L2L3),
+				     new_adapt);
+		if (err)
+			goto out;
+
+		err = ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTINITIALL0L1L2L3),
+				     &actual_adapt);
+		if (err)
+			goto out;
+
+		if (actual_adapt != new_adapt) {
+			limit_speed = true;
+			dev_warn(hba->dev, "Failed to update host PA_PeerRxHsG6AdaptInitialL0L1L2L3 to new value 0x%x, actual value = 0x%x\n",
+				 new_adapt, actual_adapt);
+		}
+	} else {
+		limit_speed = true;
+		dev_warn(hba->dev, "New PA_PeerRxHsG6AdaptInitialL0L1L2L3 value (0x%x) is too large!\n",
+			 new_adapt);
+	}
+
+	err = ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTREFRESHL0L1L2L3), &adapt_l0l1l2l3);
+	if (err)
+		goto out;
+
+	if (adapt_l0l1l2l3 > ADAPT_L0L1L2L3_LENGTH_MAX) {
+		dev_err(hba->dev, "PA_PeerRxHsG6AdaptRefreshL0L1L2L3 value (0x%x) exceeds MAX.\n",
+			adapt_l0l1l2l3);
+		err = -EINVAL;
+		goto out;
+	}
+
+	new_adapt = ufs_qcom_double_t_adapt_l0l1l2l3(adapt_l0l1l2l3);
+	dev_dbg(hba->dev, "Original PA_PeerRxHsG6AdaptRefreshL0L1L2L3 value = 0x%x, new value = 0x%x\n",
+		adapt_l0l1l2l3, new_adapt);
+
+	/*
+	 * 0x8C is the max possible value allowed by UniPro v3.0 spec, some HWs
+	 * can accept 0x8D but some cannot.
+	 */
+	if (new_adapt <= ADAPT_L0L1L2L3_LENGTH_MAX ||
+	    (new_adapt == ADAPT_L0L1L2L3_LENGTH_MAX + 1 && host->hw_ver.minor == 0x1)) {
+		err = ufshcd_dme_set(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTREFRESHL0L1L2L3),
+				     new_adapt);
+		if (err)
+			goto out;
+
+		err = ufshcd_dme_get(hba, UIC_ARG_MIB(PA_PEERRXHSG6ADAPTREFRESHL0L1L2L3),
+				     &actual_adapt);
+		if (err)
+			goto out;
+
+		if (actual_adapt != new_adapt) {
+			limit_speed = true;
+			dev_warn(hba->dev, "Failed to update host PA_PeerRxHsG6AdaptRefreshL0L1L2L3 to new value 0x%x, actual value = 0x%x\n",
+				 new_adapt, actual_adapt);
+		}
+	} else {
+		limit_speed = true;
+		dev_warn(hba->dev, "New PA_PeerRxHsG6AdaptRefreshL0L1L2L3 value (0x%x) is too large!\n",
+			 new_adapt);
+	}
+
+out:
+	if (limit_speed || err)
+		ufs_qcom_limit_max_gear(hba, UFS_HS_G5);
+}
+
 static int ufs_qcom_apply_dev_quirks(struct ufs_hba *hba)
 {
 	int err = 0;
 
+	ufs_qcom_fixup_tx_adapt_l0l1l2l3(hba);
+
 	if (hba->dev_quirks & UFS_DEVICE_QUIRK_HOST_PA_SAVECONFIGTIME)
 		err = ufs_qcom_quirk_host_pa_saveconfigtime(hba);
 
-- 
2.34.1