[PATCH 0/2] phy: qcom-qmp-pcie: Add support to keep refclk always on

[PATCH 0/2] phy: qcom-qmp-pcie: Add support to keep refclk always on

[Krishna chaitanya chundru]

This series adds support to provide refclk to endpoint even in low
power states.

Due to some platform specific issues with CLKREQ signal, it is not being
propagated to the host and as host doesn't know the clkreq signal host is
not sending refclk. Due to this endpoint is seeing linkdown and going
to bad state.
To avoid those ref clk should be provided always to the endpoint. The
issue is coming only when ep intiates the L1.1 or L1.2 exit and clkreq
is not being propagated properly to the host. 

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
Krishna chaitanya chundru (2):
      dt-bindings: phy: qcom,qmp: Add PCIe qcom,refclk-always-on property
      phy: qcom-qmp-pcie: Add support for keeping refclk always on

 .../bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml    |  5 +++++
 drivers/phy/qualcomm/phy-qcom-qmp-pcie.c            | 21 +++++++++++++++++----
 2 files changed, 22 insertions(+), 4 deletions(-)
---
base-commit: 71e68e182e382e951d6248bccc3c960dcec5a718
change-id: 20231106-refclk_always_on-9beae8297cb8

Best regards,
-- 
Krishna chaitanya chundru <quic_krichai@quicinc.com>

[PATCH 1/2] dt-bindings: phy: qcom,qmp: Add PCIe qcom,refclk-always-on property

[Krishna chaitanya chundru]

Document qcom,refclk-always-on property which is needed in some platforms
to supply refclk even in PCIe low power states.

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
 .../devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml          | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
index 2c3d6553a7ba..9daf0556ed3b 100644
--- a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
+++ b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
@@ -93,6 +93,11 @@ properties:
   "#phy-cells":
     const: 0
 
+  qcom,refclk-always-on:
+    type: boolean
+    description: A boolean property indicating the refclk is
+      always on even in Low power states (optional)
+
 required:
   - compatible
   - reg

-- 
2.42.0

[PATCH 2/2] phy: qcom-qmp-pcie: Add support for keeping refclk always on

[Krishna chaitanya chundru]

In PCIe low power states like L1.1 or L1.2 the phy will stop
supplying refclk to endpoint. If endpoint asserts clkreq to bring
back link L0, then RC needs to provide refclk to endpoint.

If there is some issues in platform with clkreq signal propagation
to host and due to that host will not send refclk which results PCIe link
down. For those platforms  phy needs to provide refclk even in low power
states.

Add a flag which indicates refclk is always supplied to endpoint.

Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
---
 drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 21 +++++++++++++++++----
 1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
index a63ca7424974..d7e377a7d96e 100644
--- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
+++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
@@ -43,6 +43,8 @@
 /* QPHY_PCS_STATUS bit */
 #define PHYSTATUS				BIT(6)
 #define PHYSTATUS_4_20				BIT(7)
+/* PCS_PCIE_ENDPOINT_REFCLK_CNTRL */
+#define EPCLK_ALWAYS_ON_EN			BIT(6)
 
 #define PHY_INIT_COMPLETE_TIMEOUT		10000
 
@@ -77,6 +79,7 @@ enum qphy_reg_layout {
 	QPHY_START_CTRL,
 	QPHY_PCS_STATUS,
 	QPHY_PCS_POWER_DOWN_CONTROL,
+	QPHY_PCS_ENDPOINT_REFCLK_CNTRL,
 	/* Keep last to ensure regs_layout arrays are properly initialized */
 	QPHY_LAYOUT_SIZE
 };
@@ -103,10 +106,11 @@ static const unsigned int sdm845_qhp_pciephy_regs_layout[QPHY_LAYOUT_SIZE] = {
 };
 
 static const unsigned int pciephy_v4_regs_layout[QPHY_LAYOUT_SIZE] = {
-	[QPHY_SW_RESET]			= QPHY_V4_PCS_SW_RESET,
-	[QPHY_START_CTRL]		= QPHY_V4_PCS_START_CONTROL,
-	[QPHY_PCS_STATUS]		= QPHY_V4_PCS_PCS_STATUS1,
-	[QPHY_PCS_POWER_DOWN_CONTROL]	= QPHY_V4_PCS_POWER_DOWN_CONTROL,
+	[QPHY_SW_RESET]				= QPHY_V4_PCS_SW_RESET,
+	[QPHY_START_CTRL]			= QPHY_V4_PCS_START_CONTROL,
+	[QPHY_PCS_STATUS]			= QPHY_V4_PCS_PCS_STATUS1,
+	[QPHY_PCS_POWER_DOWN_CONTROL]		= QPHY_V4_PCS_POWER_DOWN_CONTROL,
+	[QPHY_PCS_ENDPOINT_REFCLK_CNTRL]	= QPHY_V4_PCS_PCIE_ENDPOINT_REFCLK_CNTRL,
 };
 
 static const unsigned int pciephy_v5_regs_layout[QPHY_LAYOUT_SIZE] = {
@@ -2244,6 +2248,8 @@ struct qmp_pcie {
 	struct phy *phy;
 	int mode;
 
+	bool refclk_always_on;
+
 	struct clk_fixed_rate pipe_clk_fixed;
 };
 
@@ -3159,6 +3165,10 @@ static void qmp_pcie_init_registers(struct qmp_pcie *qmp, const struct qmp_phy_c
 	qmp_pcie_configure(pcs, tbls->pcs, tbls->pcs_num);
 	qmp_pcie_configure(pcs_misc, tbls->pcs_misc, tbls->pcs_misc_num);
 
+	if (qmp->refclk_always_on && cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL])
+		qphy_setbits(pcs_misc, cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL],
+			     EPCLK_ALWAYS_ON_EN);
+
 	if (cfg->lanes >= 4 && qmp->tcsr_4ln_config) {
 		qmp_pcie_configure(serdes, cfg->serdes_4ln_tbl, cfg->serdes_4ln_num);
 		qmp_pcie_init_port_b(qmp, tbls);
@@ -3681,6 +3691,9 @@ static int qmp_pcie_probe(struct platform_device *pdev)
 	if (ret)
 		goto err_node_put;
 
+	qmp->refclk_always_on = of_property_read_bool(dev->of_node,
+						      "qcom,refclk-always-on");
+
 	ret = phy_pipe_clk_register(qmp, np);
 	if (ret)
 		goto err_node_put;

-- 
2.42.0

Re: [PATCH 0/2] phy: qcom-qmp-pcie: Add support to keep refclk always on

[Dmitry Baryshkov]

On Mon, 6 Nov 2023 at 13:53, Krishna chaitanya chundru
<quic_krichai@quicinc.com> wrote:
>
> This series adds support to provide refclk to endpoint even in low
> power states.
>
> Due to some platform specific issues with CLKREQ signal, it is not being
> propagated to the host and as host doesn't know the clkreq signal host is
> not sending refclk. Due to this endpoint is seeing linkdown and going
> to bad state.

Is this a board issue or an SoC issue? In the latter case this should
go to the PHY configuration structure instead of being specified in
the DT.

> To avoid those ref clk should be provided always to the endpoint. The
> issue is coming only when ep intiates the L1.1 or L1.2 exit and clkreq
> is not being propagated properly to the host.
>
> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
> ---
> Krishna chaitanya chundru (2):
>       dt-bindings: phy: qcom,qmp: Add PCIe qcom,refclk-always-on property
>       phy: qcom-qmp-pcie: Add support for keeping refclk always on
>
>  .../bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml    |  5 +++++
>  drivers/phy/qualcomm/phy-qcom-qmp-pcie.c            | 21 +++++++++++++++++----
>  2 files changed, 22 insertions(+), 4 deletions(-)
> ---
> base-commit: 71e68e182e382e951d6248bccc3c960dcec5a718
> change-id: 20231106-refclk_always_on-9beae8297cb8
>
> Best regards,
> --
> Krishna chaitanya chundru <quic_krichai@quicinc.com>
>


-- 
With best wishes
Dmitry

Re: [PATCH 0/2] phy: qcom-qmp-pcie: Add support to keep refclk always on

[Krishna Chaitanya Chundru]

On 11/6/2023 5:28 PM, Dmitry Baryshkov wrote:
> On Mon, 6 Nov 2023 at 13:53, Krishna chaitanya chundru
> <quic_krichai@quicinc.com> wrote:
>> This series adds support to provide refclk to endpoint even in low
>> power states.
>>
>> Due to some platform specific issues with CLKREQ signal, it is not being
>> propagated to the host and as host doesn't know the clkreq signal host is
>> not sending refclk. Due to this endpoint is seeing linkdown and going
>> to bad state.
> Is this a board issue or an SoC issue? In the latter case this should
> go to the PHY configuration structure instead of being specified in
> the DT.

Hi Dmitry,

This is not SOC level issue it is a board issue.

- Krishna Chaitanya.

>> To avoid those ref clk should be provided always to the endpoint. The
>> issue is coming only when ep intiates the L1.1 or L1.2 exit and clkreq
>> is not being propagated properly to the host.
>>
>> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
>> ---
>> Krishna chaitanya chundru (2):
>>        dt-bindings: phy: qcom,qmp: Add PCIe qcom,refclk-always-on property
>>        phy: qcom-qmp-pcie: Add support for keeping refclk always on
>>
>>   .../bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml    |  5 +++++
>>   drivers/phy/qualcomm/phy-qcom-qmp-pcie.c            | 21 +++++++++++++++++----
>>   2 files changed, 22 insertions(+), 4 deletions(-)
>> ---
>> base-commit: 71e68e182e382e951d6248bccc3c960dcec5a718
>> change-id: 20231106-refclk_always_on-9beae8297cb8
>>
>> Best regards,
>> --
>> Krishna chaitanya chundru <quic_krichai@quicinc.com>
>>
>

Re: [PATCH 2/2] phy: qcom-qmp-pcie: Add support for keeping refclk always on

[Dmitry Baryshkov]

On Mon, 6 Nov 2023 at 13:53, Krishna chaitanya chundru
<quic_krichai@quicinc.com> wrote:
>
> In PCIe low power states like L1.1 or L1.2 the phy will stop
> supplying refclk to endpoint. If endpoint asserts clkreq to bring
> back link L0, then RC needs to provide refclk to endpoint.
>
> If there is some issues in platform with clkreq signal propagation
> to host and due to that host will not send refclk which results PCIe link
> down. For those platforms  phy needs to provide refclk even in low power
> states.
>
> Add a flag which indicates refclk is always supplied to endpoint.
>
> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
> ---
>  drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 21 +++++++++++++++++----
>  1 file changed, 17 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
> index a63ca7424974..d7e377a7d96e 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
> @@ -43,6 +43,8 @@
>  /* QPHY_PCS_STATUS bit */
>  #define PHYSTATUS                              BIT(6)
>  #define PHYSTATUS_4_20                         BIT(7)
> +/* PCS_PCIE_ENDPOINT_REFCLK_CNTRL */
> +#define EPCLK_ALWAYS_ON_EN                     BIT(6)


>
>  #define PHY_INIT_COMPLETE_TIMEOUT              10000
>
> @@ -77,6 +79,7 @@ enum qphy_reg_layout {
>         QPHY_START_CTRL,
>         QPHY_PCS_STATUS,
>         QPHY_PCS_POWER_DOWN_CONTROL,
> +       QPHY_PCS_ENDPOINT_REFCLK_CNTRL,
>         /* Keep last to ensure regs_layout arrays are properly initialized */
>         QPHY_LAYOUT_SIZE
>  };
> @@ -103,10 +106,11 @@ static const unsigned int sdm845_qhp_pciephy_regs_layout[QPHY_LAYOUT_SIZE] = {
>  };
>
>  static const unsigned int pciephy_v4_regs_layout[QPHY_LAYOUT_SIZE] = {
> -       [QPHY_SW_RESET]                 = QPHY_V4_PCS_SW_RESET,
> -       [QPHY_START_CTRL]               = QPHY_V4_PCS_START_CONTROL,
> -       [QPHY_PCS_STATUS]               = QPHY_V4_PCS_PCS_STATUS1,
> -       [QPHY_PCS_POWER_DOWN_CONTROL]   = QPHY_V4_PCS_POWER_DOWN_CONTROL,
> +       [QPHY_SW_RESET]                         = QPHY_V4_PCS_SW_RESET,
> +       [QPHY_START_CTRL]                       = QPHY_V4_PCS_START_CONTROL,
> +       [QPHY_PCS_STATUS]                       = QPHY_V4_PCS_PCS_STATUS1,
> +       [QPHY_PCS_POWER_DOWN_CONTROL]           = QPHY_V4_PCS_POWER_DOWN_CONTROL,

No unnecessary whitespace changes, please.

> +       [QPHY_PCS_ENDPOINT_REFCLK_CNTRL]        = QPHY_V4_PCS_PCIE_ENDPOINT_REFCLK_CNTRL,

Any other platform having this register?

>  };
>
>  static const unsigned int pciephy_v5_regs_layout[QPHY_LAYOUT_SIZE] = {
> @@ -2244,6 +2248,8 @@ struct qmp_pcie {
>         struct phy *phy;
>         int mode;
>
> +       bool refclk_always_on;
> +
>         struct clk_fixed_rate pipe_clk_fixed;
>  };
>
> @@ -3159,6 +3165,10 @@ static void qmp_pcie_init_registers(struct qmp_pcie *qmp, const struct qmp_phy_c
>         qmp_pcie_configure(pcs, tbls->pcs, tbls->pcs_num);
>         qmp_pcie_configure(pcs_misc, tbls->pcs_misc, tbls->pcs_misc_num);
>
> +       if (qmp->refclk_always_on && cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL])
> +               qphy_setbits(pcs_misc, cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL],
> +                            EPCLK_ALWAYS_ON_EN);
> +
>         if (cfg->lanes >= 4 && qmp->tcsr_4ln_config) {
>                 qmp_pcie_configure(serdes, cfg->serdes_4ln_tbl, cfg->serdes_4ln_num);
>                 qmp_pcie_init_port_b(qmp, tbls);
> @@ -3681,6 +3691,9 @@ static int qmp_pcie_probe(struct platform_device *pdev)
>         if (ret)
>                 goto err_node_put;
>
> +       qmp->refclk_always_on = of_property_read_bool(dev->of_node,
> +                                                     "qcom,refclk-always-on");

Error out if !cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL]).
Otherwise your DT value can be silently ignored.

> +
>         ret = phy_pipe_clk_register(qmp, np);
>         if (ret)
>                 goto err_node_put;
>
> --
> 2.42.0
>


-- 
With best wishes
Dmitry

Re: [PATCH 2/2] phy: qcom-qmp-pcie: Add support for keeping refclk always on

[Krishna Chaitanya Chundru]

On 11/6/2023 5:43 PM, Dmitry Baryshkov wrote:
> On Mon, 6 Nov 2023 at 13:53, Krishna chaitanya chundru
> <quic_krichai@quicinc.com> wrote:
>> In PCIe low power states like L1.1 or L1.2 the phy will stop
>> supplying refclk to endpoint. If endpoint asserts clkreq to bring
>> back link L0, then RC needs to provide refclk to endpoint.
>>
>> If there is some issues in platform with clkreq signal propagation
>> to host and due to that host will not send refclk which results PCIe link
>> down. For those platforms  phy needs to provide refclk even in low power
>> states.
>>
>> Add a flag which indicates refclk is always supplied to endpoint.
>>
>> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
>> ---
>>   drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 21 +++++++++++++++++----
>>   1 file changed, 17 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
>> index a63ca7424974..d7e377a7d96e 100644
>> --- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
>> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
>> @@ -43,6 +43,8 @@
>>   /* QPHY_PCS_STATUS bit */
>>   #define PHYSTATUS                              BIT(6)
>>   #define PHYSTATUS_4_20                         BIT(7)
>> +/* PCS_PCIE_ENDPOINT_REFCLK_CNTRL */
>> +#define EPCLK_ALWAYS_ON_EN                     BIT(6)
>
>>   #define PHY_INIT_COMPLETE_TIMEOUT              10000
>>
>> @@ -77,6 +79,7 @@ enum qphy_reg_layout {
>>          QPHY_START_CTRL,
>>          QPHY_PCS_STATUS,
>>          QPHY_PCS_POWER_DOWN_CONTROL,
>> +       QPHY_PCS_ENDPOINT_REFCLK_CNTRL,
>>          /* Keep last to ensure regs_layout arrays are properly initialized */
>>          QPHY_LAYOUT_SIZE
>>   };
>> @@ -103,10 +106,11 @@ static const unsigned int sdm845_qhp_pciephy_regs_layout[QPHY_LAYOUT_SIZE] = {
>>   };
>>
>>   static const unsigned int pciephy_v4_regs_layout[QPHY_LAYOUT_SIZE] = {
>> -       [QPHY_SW_RESET]                 = QPHY_V4_PCS_SW_RESET,
>> -       [QPHY_START_CTRL]               = QPHY_V4_PCS_START_CONTROL,
>> -       [QPHY_PCS_STATUS]               = QPHY_V4_PCS_PCS_STATUS1,
>> -       [QPHY_PCS_POWER_DOWN_CONTROL]   = QPHY_V4_PCS_POWER_DOWN_CONTROL,
>> +       [QPHY_SW_RESET]                         = QPHY_V4_PCS_SW_RESET,
>> +       [QPHY_START_CTRL]                       = QPHY_V4_PCS_START_CONTROL,
>> +       [QPHY_PCS_STATUS]                       = QPHY_V4_PCS_PCS_STATUS1,
>> +       [QPHY_PCS_POWER_DOWN_CONTROL]           = QPHY_V4_PCS_POWER_DOWN_CONTROL,
> No unnecessary whitespace changes, please.
I will remove above white space and keep below change as it is as it is 
throwing error as white space required there
>
>> +       [QPHY_PCS_ENDPOINT_REFCLK_CNTRL]        = QPHY_V4_PCS_PCIE_ENDPOINT_REFCLK_CNTRL,
> Any other platform having this register?
we have this register for other platforms also I will add that register 
in which ever versions it exits in next patch
>
>>   };
>>
>>   static const unsigned int pciephy_v5_regs_layout[QPHY_LAYOUT_SIZE] = {
>> @@ -2244,6 +2248,8 @@ struct qmp_pcie {
>>          struct phy *phy;
>>          int mode;
>>
>> +       bool refclk_always_on;
>> +
>>          struct clk_fixed_rate pipe_clk_fixed;
>>   };
>>
>> @@ -3159,6 +3165,10 @@ static void qmp_pcie_init_registers(struct qmp_pcie *qmp, const struct qmp_phy_c
>>          qmp_pcie_configure(pcs, tbls->pcs, tbls->pcs_num);
>>          qmp_pcie_configure(pcs_misc, tbls->pcs_misc, tbls->pcs_misc_num);
>>
>> +       if (qmp->refclk_always_on && cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL])
>> +               qphy_setbits(pcs_misc, cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL],
>> +                            EPCLK_ALWAYS_ON_EN);
>> +
>>          if (cfg->lanes >= 4 && qmp->tcsr_4ln_config) {
>>                  qmp_pcie_configure(serdes, cfg->serdes_4ln_tbl, cfg->serdes_4ln_num);
>>                  qmp_pcie_init_port_b(qmp, tbls);
>> @@ -3681,6 +3691,9 @@ static int qmp_pcie_probe(struct platform_device *pdev)
>>          if (ret)
>>                  goto err_node_put;
>>
>> +       qmp->refclk_always_on = of_property_read_bool(dev->of_node,
>> +                                                     "qcom,refclk-always-on");
> Error out if !cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL]).
> Otherwise your DT value can be silently ignored.

sure I will add this in next patch series.

- Krishna Chaitanya.

>> +
>>          ret = phy_pipe_clk_register(qmp, np);
>>          if (ret)
>>                  goto err_node_put;
>>
>> --
>> 2.42.0
>>
>

Re: [PATCH 2/2] phy: qcom-qmp-pcie: Add support for keeping refclk always on

[Bjorn Andersson]

On Mon, Nov 06, 2023 at 05:22:35PM +0530, Krishna chaitanya chundru wrote:
> In PCIe low power states like L1.1 or L1.2 the phy will stop
> supplying refclk to endpoint. If endpoint asserts clkreq to bring
> back link L0, then RC needs to provide refclk to endpoint.
> 
> If there is some issues in platform with clkreq signal propagation
> to host and due to that host will not send refclk which results PCIe link
> down. For those platforms  phy needs to provide refclk even in low power

Double <space> ------------^^

> states.
> 
> Add a flag which indicates refclk is always supplied to endpoint.
> 

The patch itself look good, the problem description looks good, but if
you have an indication that the refclk "is always supplied to the
endpoint", then you don't have a problem with refclk and I don't think
you need this patch.

Something to the tune of "keep refclk always supplied to endpoint" seems
to more appropriately describe what this flag is doing.

> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
> ---
>  drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 21 +++++++++++++++++----
>  1 file changed, 17 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
> index a63ca7424974..d7e377a7d96e 100644
> --- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
> @@ -43,6 +43,8 @@
>  /* QPHY_PCS_STATUS bit */
>  #define PHYSTATUS				BIT(6)
>  #define PHYSTATUS_4_20				BIT(7)
> +/* PCS_PCIE_ENDPOINT_REFCLK_CNTRL */
> +#define EPCLK_ALWAYS_ON_EN			BIT(6)
>  
>  #define PHY_INIT_COMPLETE_TIMEOUT		10000
>  
> @@ -77,6 +79,7 @@ enum qphy_reg_layout {
>  	QPHY_START_CTRL,
>  	QPHY_PCS_STATUS,
>  	QPHY_PCS_POWER_DOWN_CONTROL,
> +	QPHY_PCS_ENDPOINT_REFCLK_CNTRL,
>  	/* Keep last to ensure regs_layout arrays are properly initialized */
>  	QPHY_LAYOUT_SIZE
>  };
> @@ -103,10 +106,11 @@ static const unsigned int sdm845_qhp_pciephy_regs_layout[QPHY_LAYOUT_SIZE] = {
>  };
>  
>  static const unsigned int pciephy_v4_regs_layout[QPHY_LAYOUT_SIZE] = {
> -	[QPHY_SW_RESET]			= QPHY_V4_PCS_SW_RESET,
> -	[QPHY_START_CTRL]		= QPHY_V4_PCS_START_CONTROL,
> -	[QPHY_PCS_STATUS]		= QPHY_V4_PCS_PCS_STATUS1,
> -	[QPHY_PCS_POWER_DOWN_CONTROL]	= QPHY_V4_PCS_POWER_DOWN_CONTROL,
> +	[QPHY_SW_RESET]				= QPHY_V4_PCS_SW_RESET,
> +	[QPHY_START_CTRL]			= QPHY_V4_PCS_START_CONTROL,
> +	[QPHY_PCS_STATUS]			= QPHY_V4_PCS_PCS_STATUS1,
> +	[QPHY_PCS_POWER_DOWN_CONTROL]		= QPHY_V4_PCS_POWER_DOWN_CONTROL,
> +	[QPHY_PCS_ENDPOINT_REFCLK_CNTRL]	= QPHY_V4_PCS_PCIE_ENDPOINT_REFCLK_CNTRL,
>  };
>  
>  static const unsigned int pciephy_v5_regs_layout[QPHY_LAYOUT_SIZE] = {
> @@ -2244,6 +2248,8 @@ struct qmp_pcie {
>  	struct phy *phy;
>  	int mode;
>  
> +	bool refclk_always_on;
> +
>  	struct clk_fixed_rate pipe_clk_fixed;
>  };
>  
> @@ -3159,6 +3165,10 @@ static void qmp_pcie_init_registers(struct qmp_pcie *qmp, const struct qmp_phy_c
>  	qmp_pcie_configure(pcs, tbls->pcs, tbls->pcs_num);
>  	qmp_pcie_configure(pcs_misc, tbls->pcs_misc, tbls->pcs_misc_num);
>  
> +	if (qmp->refclk_always_on && cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL])
> +		qphy_setbits(pcs_misc, cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL],
> +			     EPCLK_ALWAYS_ON_EN);
> +
>  	if (cfg->lanes >= 4 && qmp->tcsr_4ln_config) {
>  		qmp_pcie_configure(serdes, cfg->serdes_4ln_tbl, cfg->serdes_4ln_num);
>  		qmp_pcie_init_port_b(qmp, tbls);
> @@ -3681,6 +3691,9 @@ static int qmp_pcie_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto err_node_put;
>  
> +	qmp->refclk_always_on = of_property_read_bool(dev->of_node,
> +						      "qcom,refclk-always-on");

Leave this line unwrapped, for readability.

Regards,
Bjorn

> +
>  	ret = phy_pipe_clk_register(qmp, np);
>  	if (ret)
>  		goto err_node_put;
> 
> -- 
> 2.42.0
> 

Re: [PATCH 1/2] dt-bindings: phy: qcom,qmp: Add PCIe qcom,refclk-always-on property

[Bjorn Andersson]

On Mon, Nov 06, 2023 at 05:22:34PM +0530, Krishna chaitanya chundru wrote:
> Document qcom,refclk-always-on property which is needed in some platforms
> to supply refclk even in PCIe low power states.
> 
> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
> ---
>  .../devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml          | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
> index 2c3d6553a7ba..9daf0556ed3b 100644
> --- a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
> +++ b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
> @@ -93,6 +93,11 @@ properties:
>    "#phy-cells":
>      const: 0
>  
> +  qcom,refclk-always-on:
> +    type: boolean
> +    description: A boolean property indicating the refclk is
> +      always on even in Low power states (optional)

As with the driver patch, please improve this description (and use your
80 characters).


It would also be preferable to capture (or at least indicate) the
problem that this flash is working around - so that future readers
doesn't need to go look in the commit history for the phy driver to
figure out what this is doing.

Regards,
Bjorn

> +
>  required:
>    - compatible
>    - reg
> 
> -- 
> 2.42.0
> 

Re: [PATCH 1/2] dt-bindings: phy: qcom,qmp: Add PCIe qcom,refclk-always-on property

[Krishna Chaitanya Chundru]

On 11/6/2023 9:50 PM, Bjorn Andersson wrote:
> On Mon, Nov 06, 2023 at 05:22:34PM +0530, Krishna chaitanya chundru wrote:
>> Document qcom,refclk-always-on property which is needed in some platforms
>> to supply refclk even in PCIe low power states.
>>
>> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
>> ---
>>   .../devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml          | 5 +++++
>>   1 file changed, 5 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
>> index 2c3d6553a7ba..9daf0556ed3b 100644
>> --- a/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
>> +++ b/Documentation/devicetree/bindings/phy/qcom,sc8280xp-qmp-pcie-phy.yaml
>> @@ -93,6 +93,11 @@ properties:
>>     "#phy-cells":
>>       const: 0
>>   
>> +  qcom,refclk-always-on:
>> +    type: boolean
>> +    description: A boolean property indicating the refclk is
>> +      always on even in Low power states (optional)
> As with the driver patch, please improve this description (and use your
> 80 characters).
>
>
> It would also be preferable to capture (or at least indicate) the
> problem that this flash is working around - so that future readers
> doesn't need to go look in the commit history for the phy driver to
> figure out what this is doing.
>
> Regards,
> Bjorn

Sure I will update this in my next patch.

- Krishna Chaitanya.

>> +
>>   required:
>>     - compatible
>>     - reg
>>
>> -- 
>> 2.42.0
>>

Re: [PATCH 2/2] phy: qcom-qmp-pcie: Add support for keeping refclk always on

[Krishna Chaitanya Chundru]

On 11/6/2023 9:47 PM, Bjorn Andersson wrote:
> On Mon, Nov 06, 2023 at 05:22:35PM +0530, Krishna chaitanya chundru wrote:
>> In PCIe low power states like L1.1 or L1.2 the phy will stop
>> supplying refclk to endpoint. If endpoint asserts clkreq to bring
>> back link L0, then RC needs to provide refclk to endpoint.
>>
>> If there is some issues in platform with clkreq signal propagation
>> to host and due to that host will not send refclk which results PCIe link
>> down. For those platforms  phy needs to provide refclk even in low power
> Double <space> ------------^^
ACK
>> states.
>>
>> Add a flag which indicates refclk is always supplied to endpoint.
>>
> The patch itself look good, the problem description looks good, but if
> you have an indication that the refclk "is always supplied to the
> endpoint", then you don't have a problem with refclk and I don't think
> you need this patch.
>
> Something to the tune of "keep refclk always supplied to endpoint" seems
> to more appropriately describe what this flag is doing.
Sure I will change it in my next patch.
>> Signed-off-by: Krishna chaitanya chundru <quic_krichai@quicinc.com>
>> ---
>>   drivers/phy/qualcomm/phy-qcom-qmp-pcie.c | 21 +++++++++++++++++----
>>   1 file changed, 17 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
>> index a63ca7424974..d7e377a7d96e 100644
>> --- a/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
>> +++ b/drivers/phy/qualcomm/phy-qcom-qmp-pcie.c
>> @@ -43,6 +43,8 @@
>>   /* QPHY_PCS_STATUS bit */
>>   #define PHYSTATUS				BIT(6)
>>   #define PHYSTATUS_4_20				BIT(7)
>> +/* PCS_PCIE_ENDPOINT_REFCLK_CNTRL */
>> +#define EPCLK_ALWAYS_ON_EN			BIT(6)
>>   
>>   #define PHY_INIT_COMPLETE_TIMEOUT		10000
>>   
>> @@ -77,6 +79,7 @@ enum qphy_reg_layout {
>>   	QPHY_START_CTRL,
>>   	QPHY_PCS_STATUS,
>>   	QPHY_PCS_POWER_DOWN_CONTROL,
>> +	QPHY_PCS_ENDPOINT_REFCLK_CNTRL,
>>   	/* Keep last to ensure regs_layout arrays are properly initialized */
>>   	QPHY_LAYOUT_SIZE
>>   };
>> @@ -103,10 +106,11 @@ static const unsigned int sdm845_qhp_pciephy_regs_layout[QPHY_LAYOUT_SIZE] = {
>>   };
>>   
>>   static const unsigned int pciephy_v4_regs_layout[QPHY_LAYOUT_SIZE] = {
>> -	[QPHY_SW_RESET]			= QPHY_V4_PCS_SW_RESET,
>> -	[QPHY_START_CTRL]		= QPHY_V4_PCS_START_CONTROL,
>> -	[QPHY_PCS_STATUS]		= QPHY_V4_PCS_PCS_STATUS1,
>> -	[QPHY_PCS_POWER_DOWN_CONTROL]	= QPHY_V4_PCS_POWER_DOWN_CONTROL,
>> +	[QPHY_SW_RESET]				= QPHY_V4_PCS_SW_RESET,
>> +	[QPHY_START_CTRL]			= QPHY_V4_PCS_START_CONTROL,
>> +	[QPHY_PCS_STATUS]			= QPHY_V4_PCS_PCS_STATUS1,
>> +	[QPHY_PCS_POWER_DOWN_CONTROL]		= QPHY_V4_PCS_POWER_DOWN_CONTROL,
>> +	[QPHY_PCS_ENDPOINT_REFCLK_CNTRL]	= QPHY_V4_PCS_PCIE_ENDPOINT_REFCLK_CNTRL,
>>   };
>>   
>>   static const unsigned int pciephy_v5_regs_layout[QPHY_LAYOUT_SIZE] = {
>> @@ -2244,6 +2248,8 @@ struct qmp_pcie {
>>   	struct phy *phy;
>>   	int mode;
>>   
>> +	bool refclk_always_on;
>> +
>>   	struct clk_fixed_rate pipe_clk_fixed;
>>   };
>>   
>> @@ -3159,6 +3165,10 @@ static void qmp_pcie_init_registers(struct qmp_pcie *qmp, const struct qmp_phy_c
>>   	qmp_pcie_configure(pcs, tbls->pcs, tbls->pcs_num);
>>   	qmp_pcie_configure(pcs_misc, tbls->pcs_misc, tbls->pcs_misc_num);
>>   
>> +	if (qmp->refclk_always_on && cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL])
>> +		qphy_setbits(pcs_misc, cfg->regs[QPHY_PCS_ENDPOINT_REFCLK_CNTRL],
>> +			     EPCLK_ALWAYS_ON_EN);
>> +
>>   	if (cfg->lanes >= 4 && qmp->tcsr_4ln_config) {
>>   		qmp_pcie_configure(serdes, cfg->serdes_4ln_tbl, cfg->serdes_4ln_num);
>>   		qmp_pcie_init_port_b(qmp, tbls);
>> @@ -3681,6 +3691,9 @@ static int qmp_pcie_probe(struct platform_device *pdev)
>>   	if (ret)
>>   		goto err_node_put;
>>   
>> +	qmp->refclk_always_on = of_property_read_bool(dev->of_node,
>> +						      "qcom,refclk-always-on");
> Leave this line unwrapped, for readability.
>
> Regards,
> Bjorn

sure I will update this in next patch.

- Krishna Chaitanya.

>> +
>>   	ret = phy_pipe_clk_register(qmp, np);
>>   	if (ret)
>>   		goto err_node_put;
>>
>> -- 
>> 2.42.0
>>