[PATCH V3 08/21] phy: tegra: p2u: Set ENABLE_L2_EXIT_RATE_CHANGE in calibration

Vidya Sagar
2022-10-13T18:43:04Z

Set ENABLE_L2_EXIT_RATE_CHANGE register bit to request UPHY PLL rate change
to Gen1 during initialization. This helps in the below surprise link down
cases,
- Surprise link down happens at Gen3/Gen4 link speed.
- Surprise link down happens and external REFCLK is cut off, which causes
UPHY PLL rate to deviate to an invalid rate.

Signed-off-by: Vidya Sagar <vidyas@nvidia.com>
---
V3:
* Removed "Reported-by: kernel test robot <lkp@intel.com>" based on Bjorn's review comment
* Reworded the commit message

V2:
* Addressed review comment from test bot and Vinod

drivers/phy/tegra/phy-tegra194-p2u.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)

diff --git a/drivers/phy/tegra/phy-tegra194-p2u.c b/drivers/phy/tegra/phy-tegra194-p2u.c
index 1415ca71de38..633e6b747275 100644
--- a/drivers/phy/tegra/phy-tegra194-p2u.c
+++ b/drivers/phy/tegra/phy-tegra194-p2u.c
@@ -15,6 +15,7 @@
#include <linux/phy/phy.h>

#define P2U_CONTROL_CMN 0x74
+#define P2U_CONTROL_CMN_ENABLE_L2_EXIT_RATE_CHANGE BIT(13)
#define P2U_CONTROL_CMN_SKP_SIZE_PROTECTION_EN BIT(20)

#define P2U_PERIODIC_EQ_CTRL_GEN3 0xc0
@@ -85,8 +86,21 @@ static int tegra_p2u_power_on(struct phy *x)
return 0;
}

+static int tegra_p2u_calibrate(struct phy *x)
+{
+ struct tegra_p2u *phy = phy_get_drvdata(x);
+ u32 val;
+
+ val = p2u_readl(phy, P2U_CONTROL_CMN);
+ val |= P2U_CONTROL_CMN_ENABLE_L2_EXIT_RATE_CHANGE;
+ p2u_writel(phy, val, P2U_CONTROL_CMN);
+
+ return 0;
+}
+
static const struct phy_ops ops = {
.power_on = tegra_p2u_power_on,
+ .calibrate = tegra_p2u_calibrate,
.owner = THIS_MODULE,
};

--
2.17.1