lkml.org 
[lkml]   [2023]   [Nov]   [7]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH 2/2] phy: qcom-qmp-pcie: Add support for keeping refclk always on
From

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
>>

\
 
 \ /
  Last update: 2023-11-20 13:51    [W:0.082 / U:0.180 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site