6.6-stable review patch. If anyone has any objections, please let me know.
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From: Siddharth Vadapalli s-vadapalli@ti.com
[ Upstream commit 22a9120479a40a56c13c5e473a0100fad2e017c0 ]
According to Section 2.2 of the PCI Express Card Electromechanical Specification (Revision 5.1), in order to ensure that the power and the reference clock are stable, PERST# has to be deasserted after a delay of 100 milliseconds (TPVPERL).
Currently, it is being assumed that the power is already stable, which is not necessarily true.
Hence, change the delay to PCIE_T_PVPERL_MS to guarantee that power and reference clock are stable.
Fixes: f3e25911a430 ("PCI: j721e: Add TI J721E PCIe driver") Fixes: f96b69713733 ("PCI: j721e: Use T_PERST_CLK_US macro") Link: https://lore.kernel.org/r/20241104074420.1862932-1-s-vadapalli@ti.com Signed-off-by: Siddharth Vadapalli s-vadapalli@ti.com Signed-off-by: Krzysztof Wilczyński kwilczynski@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/controller/cadence/pci-j721e.c | 26 ++++++++++------------ 1 file changed, 12 insertions(+), 14 deletions(-)
diff --git a/drivers/pci/controller/cadence/pci-j721e.c b/drivers/pci/controller/cadence/pci-j721e.c index 212b11c3145d8..f76a358e2b5b6 100644 --- a/drivers/pci/controller/cadence/pci-j721e.c +++ b/drivers/pci/controller/cadence/pci-j721e.c @@ -516,15 +516,14 @@ static int j721e_pcie_probe(struct platform_device *pdev) pcie->refclk = clk;
/* - * The "Power Sequencing and Reset Signal Timings" table of the - * PCI Express Card Electromechanical Specification, Revision - * 5.1, Section 2.9.2, Symbol "T_PERST-CLK", indicates PERST# - * should be deasserted after minimum of 100us once REFCLK is - * stable. The REFCLK to the connector in RC mode is selected - * while enabling the PHY. So deassert PERST# after 100 us. + * Section 2.2 of the PCI Express Card Electromechanical + * Specification (Revision 5.1) mandates that the deassertion + * of the PERST# signal should be delayed by 100 ms (TPVPERL). + * This shall ensure that the power and the reference clock + * are stable. */ if (gpiod) { - fsleep(PCIE_T_PERST_CLK_US); + msleep(PCIE_T_PVPERL_MS); gpiod_set_value_cansleep(gpiod, 1); }
@@ -615,15 +614,14 @@ static int j721e_pcie_resume_noirq(struct device *dev) return ret;
/* - * The "Power Sequencing and Reset Signal Timings" table of the - * PCI Express Card Electromechanical Specification, Revision - * 5.1, Section 2.9.2, Symbol "T_PERST-CLK", indicates PERST# - * should be deasserted after minimum of 100us once REFCLK is - * stable. The REFCLK to the connector in RC mode is selected - * while enabling the PHY. So deassert PERST# after 100 us. + * Section 2.2 of the PCI Express Card Electromechanical + * Specification (Revision 5.1) mandates that the deassertion + * of the PERST# signal should be delayed by 100 ms (TPVPERL). + * This shall ensure that the power and the reference clock + * are stable. */ if (pcie->reset_gpio) { - fsleep(PCIE_T_PERST_CLK_US); + msleep(PCIE_T_PVPERL_MS); gpiod_set_value_cansleep(pcie->reset_gpio, 1); }