This patch series contains enhancements to the pcie-tegra194.c driver
that works for both Tegra194 and Tegra234 SoCs and for both RootPort
and Endpoint modes.
Vidya Sagar (9):
PCI: tegra194: Use devm_gpiod_get_optional() to parse
"nvidia,refclk-select"
PCI: tegra194: Drive CLKREQ signal low explicitly
PCI: tegra194: Fix polling delay for L2 state
PCI: tegra194: Handle errors in BPMP response
PCI: tegra194: Apply pinctrl settings for both PCIe RP and EP
PCI: tegra194: Refactor LTSSM state polling on surprise down
PCI: tegra194: Disable direct speed change for EP
phy: tegra: p2u: Set ENABLE_L2_EXIT_RATE_CHANGE in calibration
PCI: tegra194: Calibrate P2U for endpoint mode
drivers/pci/controller/dwc/pcie-tegra194.c | 126 +++++++++++++++------
drivers/phy/tegra/phy-tegra194-p2u.c | 14 +++
2 files changed, 104 insertions(+), 36 deletions(-)
--
2.17.1
Currently, the default setting is that CLKREQ signal of a Root Port
is internally overridden to '0' to enable REFCLK flowing out to the slot.
It is observed that one of the PCIe switches (case in point Broadcom PCIe
Gen4 switch) is propagating the CLKREQ signal of the root port to the
downstream side of the switch and expecting the endpoints to pull it low
so that it (PCIe switch) can give out the REFCLK although the Switch as
such doesn't support CLK-PM or ASPM-L1SS. So, as a work-around, this patch
drives the CLKREQ of the Root Port itself low to avoid link up issues
between PCIe switch downstream port and endpoints. This is not a wrong
thing to do after all the CLKREQ is anyway being overridden to '0'
internally and now it is just that the same is being propagated outside
also.
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/controller/dwc/pcie-tegra194.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 2631685e3315..d053e52b1778 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -46,6 +46,7 @@
#define APPL_PINMUX_CLKREQ_OVERRIDE BIT(3)
#define APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE_EN BIT(4)
#define APPL_PINMUX_CLK_OUTPUT_IN_OVERRIDE BIT(5)
+#define APPL_PINMUX_CLKREQ_DEFAULT_VALUE BIT(13)
#define APPL_CTRL 0x4
#define APPL_CTRL_SYS_PRE_DET_STATE BIT(6)
@@ -1453,6 +1454,7 @@ static int tegra_pcie_config_controller(struct tegra_pcie_dw *pcie,
val = appl_readl(pcie, APPL_PINMUX);
val |= APPL_PINMUX_CLKREQ_OVERRIDE_EN;
val &= ~APPL_PINMUX_CLKREQ_OVERRIDE;
+ val &= ~APPL_PINMUX_CLKREQ_DEFAULT_VALUE;
appl_writel(pcie, val, APPL_PINMUX);
}
--
2.17.1
PERST# and CLKREQ# pinctrl settings should be applied for both root port
and endpoint mode. Move pinctrl_pm_select_default_state() function call
from root port specific configuration function to probe().
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/controller/dwc/pcie-tegra194.c | 19 +++++++++++++------
1 file changed, 13 insertions(+), 6 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 65c2c689fcd5..f96f60c49dcb 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -1659,12 +1659,6 @@ static int tegra_pcie_config_rp(struct tegra_pcie_dw *pcie)
goto fail_pm_get_sync;
}
- ret = pinctrl_pm_select_default_state(dev);
- if (ret < 0) {
- dev_err(dev, "Failed to configure sideband pins: %d\n", ret);
- goto fail_pm_get_sync;
- }
-
ret = tegra_pcie_init_controller(pcie);
if (ret < 0) {
dev_err(dev, "Failed to initialize controller: %d\n", ret);
@@ -2122,6 +2116,19 @@ static int tegra_pcie_dw_probe(struct platform_device *pdev)
pp = &pci->pp;
pp->num_vectors = MAX_MSI_IRQS;
+ ret = pinctrl_pm_select_default_state(dev);
+ if (ret < 0) {
+ const char *level = KERN_ERR;
+
+ if (ret == -EPROBE_DEFER)
+ level = KERN_DEBUG;
+
+ dev_printk(level, dev,
+ "Failed to configure sideband pins: %d\n",
+ ret);
+ return ret;
+ }
+
ret = tegra_pcie_dw_parse_dt(pcie);
if (ret < 0) {
const char *level = KERN_ERR;
--
2.17.1
Calibrate P2U for endpoint to request UPHY PLL rate change to Gen1 during
initialization.
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/controller/dwc/pcie-tegra194.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 35d9c3ac3028..67dd97f3cd6e 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -1078,6 +1078,9 @@ static int tegra_pcie_enable_phy(struct tegra_pcie_dw *pcie)
ret = phy_power_on(pcie->phys[i]);
if (ret < 0)
goto phy_exit;
+
+ if (pcie->of_data->mode == DW_PCIE_EP_TYPE)
+ phy_calibrate(pcie->phys[i]);
}
return 0;
--
2.17.1
The return value from tegra_bpmp_transfer indicates the success or
failure of the IPC transaction with BPMP. If the transaction
succeeded, we also need to check the actual command's result code.
Add code to do this.
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/controller/dwc/pcie-tegra194.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index de477192c4b8..65c2c689fcd5 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -1203,6 +1203,7 @@ static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
struct mrq_uphy_response resp;
struct tegra_bpmp_message msg;
struct mrq_uphy_request req;
+ int err;
/*
* Controller-5 doesn't need to have its state set by BPMP-FW in
@@ -1225,7 +1226,13 @@ static int tegra_pcie_bpmp_set_ctrl_state(struct tegra_pcie_dw *pcie,
msg.rx.data = &resp;
msg.rx.size = sizeof(resp);
- return tegra_bpmp_transfer(pcie->bpmp, &msg);
+ err = tegra_bpmp_transfer(pcie->bpmp, &msg);
+ if (err)
+ return err;
+ if (msg.rx.ret)
+ return -EINVAL;
+
+ return 0;
}
static int tegra_pcie_bpmp_set_pll_state(struct tegra_pcie_dw *pcie,
@@ -1234,6 +1241,7 @@ static int tegra_pcie_bpmp_set_pll_state(struct tegra_pcie_dw *pcie,
struct mrq_uphy_response resp;
struct tegra_bpmp_message msg;
struct mrq_uphy_request req;
+ int err;
memset(&req, 0, sizeof(req));
memset(&resp, 0, sizeof(resp));
@@ -1253,7 +1261,13 @@ static int tegra_pcie_bpmp_set_pll_state(struct tegra_pcie_dw *pcie,
msg.rx.data = &resp;
msg.rx.size = sizeof(resp);
- return tegra_bpmp_transfer(pcie->bpmp, &msg);
+ err = tegra_bpmp_transfer(pcie->bpmp, &msg);
+ if (err)
+ return err;
+ if (msg.rx.ret)
+ return -EINVAL;
+
+ return 0;
}
static void tegra_pcie_downstream_dev_to_D0(struct tegra_pcie_dw *pcie)
--
2.17.1
Disable direct speed change for endpoint to prevent it from doing
speed change by itself post physical layer link up at gen1 and also
to leave link speed in control of the host.
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/controller/dwc/pcie-tegra194.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index e38fedd42034..35d9c3ac3028 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -1872,6 +1872,10 @@ static void pex_ep_event_pex_rst_deassert(struct tegra_pcie_dw *pcie)
reset_control_deassert(pcie->core_rst);
+ val = dw_pcie_readl_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL);
+ val &= ~PORT_LOGIC_SPEED_CHANGE;
+ dw_pcie_writel_dbi(pci, PCIE_LINK_WIDTH_SPEED_CONTROL, val);
+
if (pcie->update_fc_fixup) {
val = dw_pcie_readl_dbi(pci, CFG_TIMER_CTRL_MAX_FUNC_NUM_OFF);
val |= 0x1 << CFG_TIMER_CTRL_ACK_NAK_SHIFT;
--
2.17.1
On surprise down LTSSM state transisition from L0 -> Recovery.RcvrLock ->
Recovery.RcvrSpeed -> Gen1 Recovery.RcvrLock -> Detect.
Recovery.RcvrLock and Recovery.RcvrSpeed time is 24 msec and 48 msec
respectively. It takes ~96 msec to move from L0 to detect state, hence,
increase the poll time to 120 msec. Disable the LTSSM state after it moves
to detect to avoid LTSSM toggle between polling and detect.
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/controller/dwc/pcie-tegra194.c | 69 ++++++++++++++--------
1 file changed, 46 insertions(+), 23 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index f96f60c49dcb..e38fedd42034 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -140,7 +140,11 @@
#define APPL_DEBUG_PM_LINKST_IN_L0 0x11
#define APPL_DEBUG_LTSSM_STATE_MASK GENMASK(8, 3)
#define APPL_DEBUG_LTSSM_STATE_SHIFT 3
-#define LTSSM_STATE_PRE_DETECT 5
+#define LTSSM_STATE_DETECT_QUIET 0x00
+#define LTSSM_STATE_DETECT_ACT 0x08
+#define LTSSM_STATE_PRE_DETECT_QUIET 0x28
+#define LTSSM_STATE_DETECT_WAIT 0x30
+#define LTSSM_STATE_L2_IDLE 0xa8
#define APPL_RADM_STATUS 0xE4
#define APPL_PM_XMT_TURNOFF_STATE BIT(0)
@@ -209,7 +213,8 @@
#define PME_ACK_DELAY 100 /* 100 us */
#define PME_ACK_TIMEOUT 10000 /* 10 ms */
-#define LTSSM_TIMEOUT 50000 /* 50ms */
+#define LTSSM_DELAY 10000 /* 10 ms */
+#define LTSSM_TIMEOUT 120000 /* 120 ms */
#define GEN3_GEN4_EQ_PRESET_INIT 5
@@ -1606,23 +1611,31 @@ static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie)
data &= ~APPL_PINMUX_PEX_RST;
appl_writel(pcie, data, APPL_PINMUX);
- /*
- * Some cards do not go to detect state even after de-asserting
- * PERST#. So, de-assert LTSSM to bring link to detect state.
- */
- data = readl(pcie->appl_base + APPL_CTRL);
- data &= ~APPL_CTRL_LTSSM_EN;
- writel(data, pcie->appl_base + APPL_CTRL);
-
err = readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG,
data,
((data &
- APPL_DEBUG_LTSSM_STATE_MASK) >>
- APPL_DEBUG_LTSSM_STATE_SHIFT) ==
- LTSSM_STATE_PRE_DETECT,
- 1, LTSSM_TIMEOUT);
+ APPL_DEBUG_LTSSM_STATE_MASK) ==
+ LTSSM_STATE_DETECT_QUIET) ||
+ ((data &
+ APPL_DEBUG_LTSSM_STATE_MASK) ==
+ LTSSM_STATE_DETECT_ACT) ||
+ ((data &
+ APPL_DEBUG_LTSSM_STATE_MASK) ==
+ LTSSM_STATE_PRE_DETECT_QUIET) ||
+ ((data &
+ APPL_DEBUG_LTSSM_STATE_MASK) ==
+ LTSSM_STATE_DETECT_WAIT),
+ LTSSM_DELAY, LTSSM_TIMEOUT);
if (err)
dev_info(pcie->dev, "Link didn't go to detect state\n");
+
+ /*
+ * Deassert LTSSM state to stop the state toggling between
+ * polling and detect.
+ */
+ data = readl(pcie->appl_base + APPL_CTRL);
+ data &= ~APPL_CTRL_LTSSM_EN;
+ writel(data, pcie->appl_base + APPL_CTRL);
}
/*
* DBI registers may not be accessible after this as PLL-E would be
@@ -1698,19 +1711,29 @@ static void pex_ep_event_pex_rst_assert(struct tegra_pcie_dw *pcie)
if (pcie->ep_state == EP_STATE_DISABLED)
return;
- /* Disable LTSSM */
+ ret = readl_poll_timeout(pcie->appl_base + APPL_DEBUG, val,
+ ((val & APPL_DEBUG_LTSSM_STATE_MASK) ==
+ LTSSM_STATE_DETECT_QUIET) ||
+ ((val & APPL_DEBUG_LTSSM_STATE_MASK) ==
+ LTSSM_STATE_DETECT_ACT) ||
+ ((val & APPL_DEBUG_LTSSM_STATE_MASK) ==
+ LTSSM_STATE_PRE_DETECT_QUIET) ||
+ ((val & APPL_DEBUG_LTSSM_STATE_MASK) ==
+ LTSSM_STATE_DETECT_WAIT) ||
+ ((val & APPL_DEBUG_LTSSM_STATE_MASK) ==
+ LTSSM_STATE_L2_IDLE),
+ LTSSM_DELAY, LTSSM_TIMEOUT);
+ if (ret)
+ dev_err(pcie->dev, "LTSSM state: 0x%x timeout: %d\n", val, ret);
+
+ /*
+ * Deassert LTSSM state to stop the state toggling between
+ * polling and detect.
+ */
val = appl_readl(pcie, APPL_CTRL);
val &= ~APPL_CTRL_LTSSM_EN;
appl_writel(pcie, val, APPL_CTRL);
- ret = readl_poll_timeout(pcie->appl_base + APPL_DEBUG, val,
- ((val & APPL_DEBUG_LTSSM_STATE_MASK) >>
- APPL_DEBUG_LTSSM_STATE_SHIFT) ==
- LTSSM_STATE_PRE_DETECT,
- 1, LTSSM_TIMEOUT);
- if (ret)
- dev_err(pcie->dev, "Failed to go Detect state: %d\n", ret);
-
reset_control_assert(pcie->core_rst);
tegra_pcie_disable_phy(pcie);
--
2.17.1
Current L2 state polling with 1us interval is too aggressive. Based on
the experiments with different endpoints, LTSSM state transisition to L2
is happening between 6us ~ 40us. Hence, update the polling delay for L2
state from 1us to 100us for a better utilization of CPU cycles.
Fixes: 56e15a238d92 ("PCI: tegra: Add Tegra194 PCIe support")
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/controller/dwc/pcie-tegra194.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index d053e52b1778..de477192c4b8 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -206,7 +206,8 @@
#define CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_MASK GENMASK(11, 8)
#define CAP_SPCIE_CAP_OFF_USP_TX_PRESET0_SHIFT 8
-#define PME_ACK_TIMEOUT 10000
+#define PME_ACK_DELAY 100 /* 100 us */
+#define PME_ACK_TIMEOUT 10000 /* 10 ms */
#define LTSSM_TIMEOUT 50000 /* 50ms */
@@ -1556,7 +1557,7 @@ static int tegra_pcie_try_link_l2(struct tegra_pcie_dw *pcie)
return readl_poll_timeout_atomic(pcie->appl_base + APPL_DEBUG, val,
val & APPL_DEBUG_PM_LINKST_IN_L2_LAT,
- 1, PME_ACK_TIMEOUT);
+ PME_ACK_DELAY, PME_ACK_TIMEOUT);
}
static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie)
--
2.17.1
Set ENABLE_L2_EXIT_RATE_CHANGE to request UPHY PLL rate change to Gen1
during initialization. This helps in the below surprise down cases,
- Surprise down happens at Gen3/Gen4 link speed
- Surprise down happens and external REFCLK is cut off which causes
UPHY PLL rate to deviate to an invalid rate
ENABLE_L2_EXIT_RATE_CHANGE needs to be set to bring the UPHY PLL rate
back to Gen1 during controller initialization for the link up.
Signed-off-by: Vidya Sagar <[email protected]>
---
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..fb710e89acac 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;
}
+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
The GPIO DT property "nvidia,refclk-select" to select the PCIe reference
clock is optional. Use devm_gpiod_get_optional() to get it.
Signed-off-by: Vidya Sagar <[email protected]>
---
drivers/pci/controller/dwc/pcie-tegra194.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c
index 1b6b437823d2..2631685e3315 100644
--- a/drivers/pci/controller/dwc/pcie-tegra194.c
+++ b/drivers/pci/controller/dwc/pcie-tegra194.c
@@ -1176,9 +1176,9 @@ static int tegra_pcie_dw_parse_dt(struct tegra_pcie_dw *pcie)
return err;
}
- pcie->pex_refclk_sel_gpiod = devm_gpiod_get(pcie->dev,
- "nvidia,refclk-select",
- GPIOD_OUT_HIGH);
+ pcie->pex_refclk_sel_gpiod = devm_gpiod_get_optional(pcie->dev,
+ "nvidia,refclk-select",
+ GPIOD_OUT_HIGH);
if (IS_ERR(pcie->pex_refclk_sel_gpiod)) {
int err = PTR_ERR(pcie->pex_refclk_sel_gpiod);
const char *level = KERN_ERR;
--
2.17.1
Hi Vidya,
Thank you for the patch! Perhaps something to improve:
[auto build test WARNING on helgaas-pci/next]
[also build test WARNING on tegra/for-next linus/master v6.0-rc6 next-20220919]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]
url: https://github.com/intel-lab-lkp/linux/commits/Vidya-Sagar/Enhancements-to-pcie-tegra194-driver/20220919-224101
base: https://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci.git next
config: ia64-allyesconfig (https://download.01.org/0day-ci/archive/20220920/[email protected]/config)
compiler: ia64-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# https://github.com/intel-lab-lkp/linux/commit/3b12c1aea8ddaae70567a332fc676c76076bf624
git remote add linux-review https://github.com/intel-lab-lkp/linux
git fetch --no-tags linux-review Vidya-Sagar/Enhancements-to-pcie-tegra194-driver/20220919-224101
git checkout 3b12c1aea8ddaae70567a332fc676c76076bf624
# save the config file
mkdir build_dir && cp config build_dir/.config
COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=ia64 SHELL=/bin/bash drivers/phy/
If you fix the issue, kindly add following tag where applicable
Reported-by: kernel test robot <[email protected]>
All warnings (new ones prefixed by >>):
>> drivers/phy/tegra/phy-tegra194-p2u.c:89:5: warning: no previous prototype for 'tegra_p2u_calibrate' [-Wmissing-prototypes]
89 | int tegra_p2u_calibrate(struct phy *x)
| ^~~~~~~~~~~~~~~~~~~
vim +/tegra_p2u_calibrate +89 drivers/phy/tegra/phy-tegra194-p2u.c
88
> 89 int tegra_p2u_calibrate(struct phy *x)
90 {
91 struct tegra_p2u *phy = phy_get_drvdata(x);
92 u32 val;
93
94 val = p2u_readl(phy, P2U_CONTROL_CMN);
95 val |= P2U_CONTROL_CMN_ENABLE_L2_EXIT_RATE_CHANGE;
96 p2u_writel(phy, val, P2U_CONTROL_CMN);
97
98 return 0;
99 }
100
--
0-DAY CI Kernel Test Service
https://01.org/lkp
On 19-09-22, 20:06, Vidya Sagar wrote:
> Set ENABLE_L2_EXIT_RATE_CHANGE to request UPHY PLL rate change to Gen1
> during initialization. This helps in the below surprise down cases,
> - Surprise down happens at Gen3/Gen4 link speed
> - Surprise down happens and external REFCLK is cut off which causes
> UPHY PLL rate to deviate to an invalid rate
>
> ENABLE_L2_EXIT_RATE_CHANGE needs to be set to bring the UPHY PLL rate
> back to Gen1 during controller initialization for the link up.
>
> Signed-off-by: Vidya Sagar <[email protected]>
> ---
> 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..fb710e89acac 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;
> }
>
> +int tegra_p2u_calibrate(struct phy *x)
why not static?
> +{
> + 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
--
~Vinod