From: Vidya Sagar Date: Thu, 3 Dec 2020 13:34:51 +0000 (+0530) Subject: PCI: tegra: Disable LTSSM during L2 entry X-Git-Tag: accepted/tizen/unified/20230118.172025~8161^2~7^2~4 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=cf68e3b7a6b75d8f0e68c80fb353cde1878ef682;p=platform%2Fkernel%2Flinux-rpi.git PCI: tegra: Disable LTSSM during L2 entry PCIe cards like Marvell SATA controller and some of the Samsung NVMe drives don't support taking the link to L2 state. When the link doesn't go to L2 state, Tegra194 requires the LTSSM to be disabled to allow PHY to start the next link up process cleanly during suspend/resume sequence. Failing to disable LTSSM results in the PCIe link not coming up in the next resume cycle. Link: https://lore.kernel.org/r/20201203133451.17716-6-vidyas@nvidia.com Tested-by: Thierry Reding Signed-off-by: Vidya Sagar Signed-off-by: Lorenzo Pieralisi Acked-by: Thierry Reding --- diff --git a/drivers/pci/controller/dwc/pcie-tegra194.c b/drivers/pci/controller/dwc/pcie-tegra194.c index f4109d7..5597b2a 100644 --- a/drivers/pci/controller/dwc/pcie-tegra194.c +++ b/drivers/pci/controller/dwc/pcie-tegra194.c @@ -1506,6 +1506,14 @@ 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 & @@ -1513,14 +1521,8 @@ static void tegra_pcie_dw_pme_turnoff(struct tegra_pcie_dw *pcie) APPL_DEBUG_LTSSM_STATE_SHIFT) == LTSSM_STATE_PRE_DETECT, 1, LTSSM_TIMEOUT); - if (err) { + if (err) dev_info(pcie->dev, "Link didn't go to detect state\n"); - } else { - /* Disable LTSSM after link is in detect state */ - data = appl_readl(pcie, APPL_CTRL); - data &= ~APPL_CTRL_LTSSM_EN; - appl_writel(pcie, data, APPL_CTRL); - } } /* * DBI registers may not be accessible after this as PLL-E would be