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Subject[PATCH v4 2/7] scsi: ufs-qcom: Add reset control support for host controller
Date
Add reset control for host controller so that host controller can be reset
as required in its power up sequence.

Signed-off-by: Can Guo <cang@codeaurora.org>
---
drivers/scsi/ufs/ufs-qcom.c | 53 +++++++++++++++++++++++++++++++++++++++++++++
drivers/scsi/ufs/ufs-qcom.h | 3 +++
2 files changed, 56 insertions(+)

diff --git a/drivers/scsi/ufs/ufs-qcom.c b/drivers/scsi/ufs/ufs-qcom.c
index a5b7148..c69c29a1c 100644
--- a/drivers/scsi/ufs/ufs-qcom.c
+++ b/drivers/scsi/ufs/ufs-qcom.c
@@ -246,6 +246,44 @@ static void ufs_qcom_select_unipro_mode(struct ufs_qcom_host *host)
mb();
}

+/**
+ * ufs_qcom_host_reset - reset host controller and PHY
+ */
+static int ufs_qcom_host_reset(struct ufs_hba *hba)
+{
+ int ret = 0;
+ struct ufs_qcom_host *host = ufshcd_get_variant(hba);
+
+ if (!host->core_reset) {
+ dev_warn(hba->dev, "%s: reset control not set\n", __func__);
+ goto out;
+ }
+
+ ret = reset_control_assert(host->core_reset);
+ if (ret) {
+ dev_err(hba->dev, "%s: core_reset assert failed, err = %d\n",
+ __func__, ret);
+ goto out;
+ }
+
+ /*
+ * The hardware requirement for delay between assert/deassert
+ * is at least 3-4 sleep clock (32.7KHz) cycles, which comes to
+ * ~125us (4/32768). To be on the safe side add 200us delay.
+ */
+ usleep_range(200, 210);
+
+ ret = reset_control_deassert(host->core_reset);
+ if (ret)
+ dev_err(hba->dev, "%s: core_reset deassert failed, err = %d\n",
+ __func__, ret);
+
+ usleep_range(1000, 1100);
+
+out:
+ return ret;
+}
+
static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
{
struct ufs_qcom_host *host = ufshcd_get_variant(hba);
@@ -254,6 +292,12 @@ static int ufs_qcom_power_up_sequence(struct ufs_hba *hba)
bool is_rate_B = (UFS_QCOM_LIMIT_HS_RATE == PA_HS_MODE_B)
? true : false;

+ /* Reset UFS Host Controller and PHY */
+ ret = ufs_qcom_host_reset(hba);
+ if (ret)
+ dev_warn(hba->dev, "%s: host reset returned %d\n",
+ __func__, ret);
+
if (is_rate_B)
phy_set_mode(phy, PHY_MODE_UFS_HS_B);

@@ -1101,6 +1145,15 @@ static int ufs_qcom_init(struct ufs_hba *hba)
host->hba = hba;
ufshcd_set_variant(hba, host);

+ /* Setup the reset control of HCI */
+ host->core_reset = devm_reset_control_get(hba->dev, "rst");
+ if (IS_ERR(host->core_reset)) {
+ err = PTR_ERR(host->core_reset);
+ dev_warn(dev, "Failed to get reset control %d\n", err);
+ host->core_reset = NULL;
+ err = 0;
+ }
+
/* Fire up the reset controller. Failure here is non-fatal. */
host->rcdev.of_node = dev->of_node;
host->rcdev.ops = &ufs_qcom_reset_ops;
diff --git a/drivers/scsi/ufs/ufs-qcom.h b/drivers/scsi/ufs/ufs-qcom.h
index d401f17..2d95e7c 100644
--- a/drivers/scsi/ufs/ufs-qcom.h
+++ b/drivers/scsi/ufs/ufs-qcom.h
@@ -6,6 +6,7 @@
#define UFS_QCOM_H_

#include <linux/reset-controller.h>
+#include <linux/reset.h>

#define MAX_UFS_QCOM_HOSTS 1
#define MAX_U32 (~(u32)0)
@@ -233,6 +234,8 @@ struct ufs_qcom_host {
u32 dbg_print_en;
struct ufs_qcom_testbus testbus;

+ /* Reset control of HCI */
+ struct reset_control *core_reset;
struct reset_controller_dev rcdev;

struct gpio_desc *device_reset;
--
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project
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