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Thu, 12 Oct 2017 13:52:33 -0700 (PDT) Received: from ban.mtv.corp.google.com ([172.22.113.17]) by smtp.gmail.com with ESMTPSA id h1sm25048704pgp.37.2017.10.12.13.52.32 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Thu, 12 Oct 2017 13:52:33 -0700 (PDT) From: Brian Norris To: Bjorn Helgaas Subject: [PATCH 2/3] of/pci: Add of_pci_get_pcie_reset_suspend() to parse pcie-reset-suspend Date: Thu, 12 Oct 2017 13:52:19 -0700 Message-Id: <20171012205220.130048-3-briannorris@chromium.org> X-Mailer: git-send-email 2.15.0.rc0.271.g36b669edcc-goog In-Reply-To: <20171012205220.130048-1-briannorris@chromium.org> References: <20171012205220.130048-1-briannorris@chromium.org> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20171012_135252_587464_58B684AB X-CRM114-Status: GOOD ( 13.04 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , devicetree@vger.kernel.org, Heiko Stuebner , linux-pci@vger.kernel.org, Shawn Lin , Brian Norris , linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org, Rob Herring , Rajat Jain , Frank Rowand , linux-arm-kernel@lists.infradead.org MIME-Version: 1.0 Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+patchwork-linux-arm=patchwork.kernel.org@lists.infradead.org X-Virus-Scanned: ClamAV using ClamSMTP This helper can be used by drivers to determine the expected PERST# behavior when in low-power system suspend (e.g., S3). I've found the expected behavior to vary across a few different endpoint implementations. Signed-off-by: Brian Norris --- drivers/of/of_pci.c | 25 +++++++++++++++++++++++++ include/linux/of_pci.h | 7 +++++++ 2 files changed, 32 insertions(+) diff --git a/drivers/of/of_pci.c b/drivers/of/of_pci.c index e9ec931f5b9a..ab2586f86094 100644 --- a/drivers/of/of_pci.c +++ b/drivers/of/of_pci.c @@ -137,6 +137,31 @@ int of_pci_get_max_link_speed(struct device_node *node) } EXPORT_SYMBOL_GPL(of_pci_get_max_link_speed); +/** + * This function returns true if the PCIe controller should assert PCIe Reset + * (PERST#) when entering system suspend (e.g., S3). + * + * @node: device tree node with the reset property + * + * Returns 1 (meaning "assert reset") or 0 ("don't assert reset"), if the DT + * defined a valid behavior. Otherwise, returns a negative error code. + */ +int of_pci_get_pcie_reset_suspend(struct device_node *node) +{ + int ret; + u32 val; + + ret = of_property_read_u32(node, "pcie-reset-suspend", &val); + if (ret) + return ret; + + if (val > 1) + return -EINVAL; + + return val; +} +EXPORT_SYMBOL_GPL(of_pci_get_pcie_reset_suspend); + /** * of_pci_check_probe_only - Setup probe only mode if linux,pci-probe-only * is present and valid diff --git a/include/linux/of_pci.h b/include/linux/of_pci.h index 518c8d20647a..df453893080b 100644 --- a/include/linux/of_pci.h +++ b/include/linux/of_pci.h @@ -17,6 +17,7 @@ int of_irq_parse_and_map_pci(const struct pci_dev *dev, u8 slot, u8 pin); int of_pci_parse_bus_range(struct device_node *node, struct resource *res); int of_get_pci_domain_nr(struct device_node *node); int of_pci_get_max_link_speed(struct device_node *node); +int of_pci_get_pcie_reset_suspend(struct device_node *node); void of_pci_check_probe_only(void); int of_pci_map_rid(struct device_node *np, u32 rid, const char *map_name, const char *map_mask_name, @@ -69,6 +70,12 @@ of_pci_get_max_link_speed(struct device_node *node) return -EINVAL; } +static inline int +of_pci_get_pcie_reset_suspend(struct device_node *node) +{ + return -EINVAL; +} + static inline void of_pci_check_probe_only(void) { } #endif