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Mon, 04 Mar 2024 01:24:08 -0800 (PST) From: Manivannan Sadhasivam Date: Mon, 04 Mar 2024 14:52:20 +0530 Subject: [PATCH v9 08/10] PCI: dwc: ep: Add a generic dw_pcie_ep_linkdown() API to handle LINK_DOWN event Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240304-pci-dbi-rework-v9-8-29d433d99cda@linaro.org> References: <20240304-pci-dbi-rework-v9-0-29d433d99cda@linaro.org> In-Reply-To: <20240304-pci-dbi-rework-v9-0-29d433d99cda@linaro.org> To: Jingoo Han , Gustavo Pimentel , Lorenzo Pieralisi , =?utf-8?q?Krzysztof_Wilczy?= =?utf-8?q?=C5=84ski?= , Rob Herring , Bjorn Helgaas , Marek Vasut , Yoshihiro Shimoda , Thierry Reding , Jonathan Hunter , Kishon Vijay Abraham I , Vidya Sagar , Vignesh Raghavendra , Richard Zhu , Lucas Stach , Shawn Guo , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , NXP Linux Team , Minghuan Lian , Mingkai Hu , Roy Zang , Kunihiko Hayashi , Masami Hiramatsu , Kishon Vijay Abraham I , Jesper Nilsson , Srikanth Thokala Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-arm-msm@vger.kernel.org, linux-tegra@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, Niklas Cassel , linux-arm-kernel@axis.com, Manivannan Sadhasivam X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=openpgp-sha256; l=6608; i=manivannan.sadhasivam@linaro.org; h=from:subject:message-id; bh=xgOAPReEJUOUSBbq55ieo+WguRSIcL9ZHZoCKItajLk=; b=owEBbQGS/pANAwAKAVWfEeb+kc71AcsmYgBl5ZLYtskHlXQ3QZgExsN5RA1FP9N/GDLnjzUGH kRLsANy4nOJATMEAAEKAB0WIQRnpUMqgUjL2KRYJ5dVnxHm/pHO9QUCZeWS2AAKCRBVnxHm/pHO 9VyMB/4yPbhV7BnfjQ7iJT41Ka8VybDCRRkNm0C7sKKBhcaHq1riRDs/JMnNLA2dQWxrkfZGT3d R8CWA2JwwwfVZndAw/ZCieNB4niqKfzKoxLoY5kpj3zNSXkqa2tRrMIOjzrtlft8yyK0LoVHvk4 8HMNKJK+Ke+eTMD1PENFMLWtRGEGQT518TSpUMu6C8RrLQgSIsE8Qxi1NsFSEXJRI1oGXZjUhYN jo6eMu2S/mKrrQMt/hxHRxzc5TXfDPf0jfaQIAkrsDzGrvwRCw0/8X9ORAMr6d2NxPjUCWhVp7z nhlCJDofqRlh4Hgs8DOSbg84xzb21K7cqgaPclQVLe+G+RlB X-Developer-Key: i=manivannan.sadhasivam@linaro.org; a=openpgp; fpr=C668AEC3C3188E4C611465E7488550E901166008 The PCIe link can go to LINK_DOWN state in one of the following scenarios: 1. Fundamental (PERST#)/hot/warm reset 2. Link transition from L2/L3 to L0 In those cases, LINK_DOWN causes some non-sticky DWC registers to loose the state (like REBAR, PTM_CAP etc...). So the drivers need to reinitialize them to function properly once the link comes back again. This is not a problem for drivers supporting PERST# IRQ, since they can reinitialize the registers in the PERST# IRQ callback. But for the drivers not supporting PERST#, there is no way they can reinitialize the registers other than relying on LINK_DOWN IRQ received when the link goes down. So let's add a DWC generic API dw_pcie_ep_linkdown() that reinitializes the non-sticky registers and also notifies the EPF drivers about link going down. This API can also be used by the drivers supporting PERST# to handle the scenario (2) mentioned above. Signed-off-by: Manivannan Sadhasivam --- drivers/pci/controller/dwc/pcie-designware-ep.c | 111 ++++++++++++++---------- drivers/pci/controller/dwc/pcie-designware.h | 5 ++ 2 files changed, 72 insertions(+), 44 deletions(-) diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c index 278bdc9b2269..fed4c2936c78 100644 --- a/drivers/pci/controller/dwc/pcie-designware-ep.c +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c @@ -14,14 +14,6 @@ #include #include -void dw_pcie_ep_linkup(struct dw_pcie_ep *ep) -{ - struct pci_epc *epc = ep->epc; - - pci_epc_linkup(epc); -} -EXPORT_SYMBOL_GPL(dw_pcie_ep_linkup); - void dw_pcie_ep_init_notify(struct dw_pcie_ep *ep) { struct pci_epc *epc = ep->epc; @@ -603,19 +595,56 @@ static unsigned int dw_pcie_ep_find_ext_capability(struct dw_pcie *pci, int cap) return 0; } +static void dw_pcie_ep_init_non_sticky_registers(struct dw_pcie *pci) +{ + unsigned int offset, ptm_cap_base; + unsigned int nbars; + u32 reg, i; + + offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR); + ptm_cap_base = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_PTM); + + dw_pcie_dbi_ro_wr_en(pci); + + if (offset) { + reg = dw_pcie_readl_dbi(pci, offset + PCI_REBAR_CTRL); + nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >> + PCI_REBAR_CTRL_NBAR_SHIFT; + + for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL) + dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0); + } + + /* + * PTM responder capability can be disabled only after disabling + * PTM root capability. + */ + if (ptm_cap_base) { + dw_pcie_dbi_ro_wr_en(pci); + reg = dw_pcie_readl_dbi(pci, ptm_cap_base + PCI_PTM_CAP); + reg &= ~PCI_PTM_CAP_ROOT; + dw_pcie_writel_dbi(pci, ptm_cap_base + PCI_PTM_CAP, reg); + + reg = dw_pcie_readl_dbi(pci, ptm_cap_base + PCI_PTM_CAP); + reg &= ~(PCI_PTM_CAP_RES | PCI_PTM_GRANULARITY_MASK); + dw_pcie_writel_dbi(pci, ptm_cap_base + PCI_PTM_CAP, reg); + dw_pcie_dbi_ro_wr_dis(pci); + } + + dw_pcie_setup(pci); + dw_pcie_dbi_ro_wr_dis(pci); +} + int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep) { struct dw_pcie *pci = to_dw_pcie_from_ep(ep); struct dw_pcie_ep_func *ep_func; struct device *dev = pci->dev; struct pci_epc *epc = ep->epc; - unsigned int offset, ptm_cap_base; - unsigned int nbars; u8 hdr_type; u8 func_no; - int i, ret; void *addr; - u32 reg; + int ret; hdr_type = dw_pcie_readb_dbi(pci, PCI_HEADER_TYPE) & PCI_HEADER_TYPE_MASK; @@ -678,38 +707,7 @@ int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep) if (ep->ops->init) ep->ops->init(ep); - offset = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_REBAR); - ptm_cap_base = dw_pcie_ep_find_ext_capability(pci, PCI_EXT_CAP_ID_PTM); - - dw_pcie_dbi_ro_wr_en(pci); - - if (offset) { - reg = dw_pcie_readl_dbi(pci, offset + PCI_REBAR_CTRL); - nbars = (reg & PCI_REBAR_CTRL_NBAR_MASK) >> - PCI_REBAR_CTRL_NBAR_SHIFT; - - for (i = 0; i < nbars; i++, offset += PCI_REBAR_CTRL) - dw_pcie_writel_dbi(pci, offset + PCI_REBAR_CAP, 0x0); - } - - /* - * PTM responder capability can be disabled only after disabling - * PTM root capability. - */ - if (ptm_cap_base) { - dw_pcie_dbi_ro_wr_en(pci); - reg = dw_pcie_readl_dbi(pci, ptm_cap_base + PCI_PTM_CAP); - reg &= ~PCI_PTM_CAP_ROOT; - dw_pcie_writel_dbi(pci, ptm_cap_base + PCI_PTM_CAP, reg); - - reg = dw_pcie_readl_dbi(pci, ptm_cap_base + PCI_PTM_CAP); - reg &= ~(PCI_PTM_CAP_RES | PCI_PTM_GRANULARITY_MASK); - dw_pcie_writel_dbi(pci, ptm_cap_base + PCI_PTM_CAP, reg); - dw_pcie_dbi_ro_wr_dis(pci); - } - - dw_pcie_setup(pci); - dw_pcie_dbi_ro_wr_dis(pci); + dw_pcie_ep_init_non_sticky_registers(pci); return 0; @@ -720,6 +718,31 @@ int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep) } EXPORT_SYMBOL_GPL(dw_pcie_ep_init_registers); +void dw_pcie_ep_linkup(struct dw_pcie_ep *ep) +{ + struct pci_epc *epc = ep->epc; + + pci_epc_linkup(epc); +} +EXPORT_SYMBOL_GPL(dw_pcie_ep_linkup); + +void dw_pcie_ep_linkdown(struct dw_pcie_ep *ep) +{ + struct dw_pcie *pci = to_dw_pcie_from_ep(ep); + struct pci_epc *epc = ep->epc; + + /* + * Initialize the non-sticky DWC registers as they would've reset post + * LINK_DOWN. This is specifically needed for drivers not supporting + * PERST# as they have no way to reinitialize the registers before the + * link comes back again. + */ + dw_pcie_ep_init_non_sticky_registers(pci); + + pci_epc_linkdown(epc); +} +EXPORT_SYMBOL_GPL(dw_pcie_ep_linkdown); + int dw_pcie_ep_init(struct dw_pcie_ep *ep) { int ret; diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h index f8e5431a207b..152969545b0a 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h @@ -668,6 +668,7 @@ static inline void __iomem *dw_pcie_own_conf_map_bus(struct pci_bus *bus, #ifdef CONFIG_PCIE_DW_EP void dw_pcie_ep_linkup(struct dw_pcie_ep *ep); +void dw_pcie_ep_linkdown(struct dw_pcie_ep *ep); int dw_pcie_ep_init(struct dw_pcie_ep *ep); int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep); void dw_pcie_ep_init_notify(struct dw_pcie_ep *ep); @@ -688,6 +689,10 @@ static inline void dw_pcie_ep_linkup(struct dw_pcie_ep *ep) { } +static inline void dw_pcie_ep_linkdown(struct dw_pcie_ep *ep) +{ +} + static inline int dw_pcie_ep_init(struct dw_pcie_ep *ep) { return 0;