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[83.9.31.12]) by smtp.gmail.com with ESMTPSA id lg25-20020a170907181900b00a3c1e1ca800sm973242ejc.11.2024.02.10.09.10.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 10 Feb 2024 09:10:16 -0800 (PST) From: Konrad Dybcio Date: Sat, 10 Feb 2024 18:10:07 +0100 Subject: [PATCH v2 3/3] PCI: qcom: properly implement RC shutdown/power up Precedence: bulk X-Mailing-List: linux-arm-msm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240210-topic-8280_pcie-v2-3-1cef4b606883@linaro.org> References: <20240210-topic-8280_pcie-v2-0-1cef4b606883@linaro.org> In-Reply-To: <20240210-topic-8280_pcie-v2-0-1cef4b606883@linaro.org> To: Bjorn Andersson , Manivannan Sadhasivam , Lorenzo Pieralisi , =?utf-8?q?Krzysztof_Wilczy?= =?utf-8?q?=C5=84ski?= , Rob Herring , Bjorn Helgaas , Philipp Zabel Cc: linux-arm-msm@vger.kernel.org, linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, Johan Hovold , Konrad Dybcio , Bjorn Andersson X-Mailer: b4 0.13-dev-0438c Currently, we've only been minimizing the power draw while keeping the RC up at all times. This is suboptimal, as it draws a whole lot of power and prevents the SoC from power collapsing. Implement full shutdown and re-initialization to allow for powering off the controller. This is mainly indended for SC8280XP with a broken power rail setup, which requires a full RC shutdown/reinit in order to reach SoC-wide power collapse, but sleeping is generally better than not sleeping and less destructive suspend can be implemented later for platforms that support it. Co-developed-by: Bjorn Andersson Signed-off-by: Konrad Dybcio --- drivers/pci/controller/dwc/Kconfig | 1 + drivers/pci/controller/dwc/pcie-qcom.c | 159 ++++++++++++++++++++++++++------- 2 files changed, 126 insertions(+), 34 deletions(-) diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig index 8afacc90c63b..4ce266951cb6 100644 --- a/drivers/pci/controller/dwc/Kconfig +++ b/drivers/pci/controller/dwc/Kconfig @@ -268,6 +268,7 @@ config PCIE_DW_PLAT_EP config PCIE_QCOM bool "Qualcomm PCIe controller (host mode)" depends on OF && (ARCH_QCOM || COMPILE_TEST) + depends on QCOM_COMMAND_DB || QCOM_COMMAND_DB=n depends on PCI_MSI select PCIE_DW_HOST select CRC8 diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controller/dwc/pcie-qcom.c index 6a469ed213ce..c807833ee4a7 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -30,13 +30,18 @@ #include #include #include +#include #include "../../pci.h" #include "pcie-designware.h" +#include +#include + /* PARF registers */ #define PARF_SYS_CTRL 0x00 #define PARF_PM_CTRL 0x20 +#define PARF_PM_STTS 0x24 #define PARF_PCS_DEEMPH 0x34 #define PARF_PCS_SWING 0x38 #define PARF_PHY_CTRL 0x40 @@ -80,7 +85,10 @@ #define L1_CLK_RMV_DIS BIT(1) /* PARF_PM_CTRL register fields */ -#define REQ_NOT_ENTR_L1 BIT(5) +#define REQ_NOT_ENTR_L1 BIT(5) /* "Prevent L0->L1" */ + +/* PARF_PM_STTS register fields */ +#define PM_ENTER_L23 BIT(5) /* PARF_PCS_DEEMPH register fields */ #define PCS_DEEMPH_TX_DEEMPH_GEN1(x) FIELD_PREP(GENMASK(21, 16), x) @@ -122,6 +130,7 @@ /* ELBI_SYS_CTRL register fields */ #define ELBI_SYS_CTRL_LT_ENABLE BIT(0) +#define ELBI_SYS_CTRL_PME_TURNOFF_MSG BIT(4) /* AXI_MSTR_RESP_COMP_CTRL0 register fields */ #define CFG_REMOTE_RD_REQ_BRIDGE_SIZE_2K 0x4 @@ -243,6 +252,7 @@ struct qcom_pcie { const struct qcom_pcie_cfg *cfg; struct dentry *debugfs; bool suspended; + bool soc_is_rpmh; }; #define to_qcom_pcie(x) dev_get_drvdata((x)->dev) @@ -272,6 +282,24 @@ static int qcom_pcie_start_link(struct dw_pcie *pci) return 0; } +static int qcom_pcie_stop_link(struct dw_pcie *pci) +{ + struct qcom_pcie *pcie = to_qcom_pcie(pci); + u32 ret_l23, val; + + writel(ELBI_SYS_CTRL_PME_TURNOFF_MSG, pcie->elbi + ELBI_SYS_CTRL); + readl(pcie->elbi + ELBI_SYS_CTRL); + + ret_l23 = readl_poll_timeout(pcie->parf + PARF_PM_STTS, val, + val & PM_ENTER_L23, 10000, 100000); + if (ret_l23) { + dev_err(pci->dev, "Failed to enter L2/L3\n"); + return -ETIMEDOUT; + } + + return 0; +} + static void qcom_pcie_clear_hpc(struct dw_pcie *pci) { u16 offset = dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); @@ -987,9 +1015,19 @@ static void qcom_pcie_host_post_init_2_7_0(struct qcom_pcie *pcie) static void qcom_pcie_deinit_2_7_0(struct qcom_pcie *pcie) { struct qcom_pcie_resources_2_7_0 *res = &pcie->res.v2_7_0; + u32 val; + + /* Disable PCIe clocks and resets */ + val = readl(pcie->parf + PARF_PHY_CTRL); + val |= PHY_TEST_PWR_DOWN; + writel(val, pcie->parf + PARF_PHY_CTRL); + readl(pcie->parf + PARF_PHY_CTRL); clk_bulk_disable_unprepare(res->num_clks, res->clks); + reset_control_assert(res->rst); + usleep_range(2000, 2500); + regulator_bulk_disable(ARRAY_SIZE(res->supplies), res->supplies); } @@ -1545,6 +1583,9 @@ static int qcom_pcie_probe(struct platform_device *pdev) goto err_phy_exit; } + /* If the soc features RPMh, cmd_db must have been prepared by now */ + pcie->soc_is_rpmh = !cmd_db_ready(); + qcom_pcie_icc_update(pcie); if (pcie->mhi) @@ -1561,58 +1602,108 @@ static int qcom_pcie_probe(struct platform_device *pdev) return ret; } -static int qcom_pcie_suspend_noirq(struct device *dev) +static int qcom_pcie_resume_noirq(struct device *dev) { struct qcom_pcie *pcie = dev_get_drvdata(dev); int ret; - /* - * Set minimum bandwidth required to keep data path functional during - * suspend. - */ - ret = icc_set_bw(pcie->icc_mem, 0, kBps_to_icc(1)); - if (ret) { - dev_err(dev, "Failed to set interconnect bandwidth: %d\n", ret); - return ret; + if (pcie->soc_is_rpmh) { + /* + * Undo the tag change from qcom_pcie_suspend_noirq first in + * case RPMh spontaneously decides to power collapse the + * platform based on other inputs. + */ + icc_set_tag(pcie->icc_mem, QCOM_ICC_TAG_ALWAYS); + + /* Flush the tag change */ + ret = icc_enable(pcie->icc_mem); + if (ret) { + dev_err(pcie->pci->dev, "failed to icc_enable: %d", ret); + return ret; + } } - /* - * Turn OFF the resources only for controllers without active PCIe - * devices. For controllers with active devices, the resources are kept - * ON and the link is expected to be in L0/L1 (sub)states. - * - * Turning OFF the resources for controllers with active PCIe devices - * will trigger access violation during the end of the suspend cycle, - * as kernel tries to access the PCIe devices config space for masking - * MSIs. - * - * Also, it is not desirable to put the link into L2/L3 state as that - * implies VDD supply will be removed and the devices may go into - * powerdown state. This will affect the lifetime of the storage devices - * like NVMe. - */ - if (!dw_pcie_link_up(pcie->pci)) { - qcom_pcie_host_deinit(&pcie->pci->pp); - pcie->suspended = true; - } + /* Only check this now to make sure the icc tag has been set. */ + if (!pcie->suspended) + return 0; + + ret = qcom_pcie_host_init(&pcie->pci->pp); + if (ret) + goto revert_icc_tag; + + dw_pcie_setup_rc(&pcie->pci->pp); + + ret = qcom_pcie_start_link(pcie->pci); + if (ret) + goto deinit_host; + + /* Ignore the retval, the devices may come up later. */ + dw_pcie_wait_for_link(pcie->pci); + + qcom_pcie_icc_update(pcie); + + pcie->suspended = false; return 0; + +deinit_host: + qcom_pcie_host_deinit(&pcie->pci->pp); +revert_icc_tag: + if (pcie->soc_is_rpmh) { + icc_set_tag(pcie->icc_mem, QCOM_ICC_TAG_WAKE); + + /* Ignore the retval, failing here would be tragic anyway.. */ + icc_enable(pcie->icc_mem); + } + + return ret; } -static int qcom_pcie_resume_noirq(struct device *dev) +static int qcom_pcie_suspend_noirq(struct device *dev) { struct qcom_pcie *pcie = dev_get_drvdata(dev); int ret; - if (pcie->suspended) { - ret = qcom_pcie_host_init(&pcie->pci->pp); + if (pcie->suspended) + return 0; + + if (dw_pcie_link_up(pcie->pci)) { + ret = qcom_pcie_stop_link(pcie->pci); if (ret) return ret; + } - pcie->suspended = false; + qcom_pcie_host_deinit(&pcie->pci->pp); + + if (pcie->soc_is_rpmh) { + /* + * The PCIe RC may be covertly accessed by the secure firmware + * on sleep exit. Use the WAKE bucket to let RPMh pull the plug + * on PCIe in sleep, but guarantee it comes back up for resume. + */ + icc_set_tag(pcie->icc_mem, QCOM_ICC_TAG_WAKE); + + /* Flush the tag change */ + ret = icc_enable(pcie->icc_mem); + if (ret) { + dev_err(pcie->pci->dev, "failed to icc_enable %d\n", ret); + + /* Revert everything and pray icc calls succeed */ + return qcom_pcie_resume_noirq(dev); + } + } else { + /* + * Set minimum bandwidth required to keep data path functional + * during suspend. + */ + ret = icc_set_bw(pcie->icc_mem, 0, kBps_to_icc(1)); + if (ret) { + dev_err(dev, "Failed to set interconnect bandwidth: %d\n", ret); + return ret; + } } - qcom_pcie_icc_update(pcie); + pcie->suspended = true; return 0; }