From 4ec36dfeb155b72da8d28ab006a46f2f8b981eac Mon Sep 17 00:00:00 2001 From: Amey Narkhede Date: Tue, 17 Aug 2021 23:34:55 +0530 Subject: PCI: Remove reset_fn field from pci_dev "reset_fn" indicates whether the device supports any reset mechanism. Remove the use of reset_fn in favor of the reset_methods array that tracks supported reset mechanisms of a device and their ordering. The octeon driver incorrectly used reset_fn to detect whether the device supports FLR or not. Use pcie_reset_flr() to probe whether it supports FLR. Co-developed-by: Alex Williamson Link: https://lore.kernel.org/r/20210817180500.1253-5-ameynarkhede03@gmail.com Signed-off-by: Alex Williamson Signed-off-by: Amey Narkhede Signed-off-by: Bjorn Helgaas Reviewed-by: Alex Williamson Reviewed-by: Raphael Norwitz --- drivers/pci/pci-sysfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/pci/pci-sysfs.c') diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index 5d63df7c1820..a1d9b0e83615 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1367,7 +1367,7 @@ static umode_t pci_dev_reset_attr_is_visible(struct kobject *kobj, { struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj)); - if (!pdev->reset_fn) + if (!pci_reset_supported(pdev)) return 0; return a->mode; -- cgit v1.2.3 From d88f521da3efd698e36d0d504a2abba6ac4f5ef8 Mon Sep 17 00:00:00 2001 From: Amey Narkhede Date: Tue, 17 Aug 2021 23:34:56 +0530 Subject: PCI: Allow userspace to query and set device reset mechanism Add "reset_method" sysfs attribute to enable user to query and set preferred device reset methods and their ordering. [bhelgaas: on invalid sysfs input, return error and preserve previous config, as in earlier patch versions] Co-developed-by: Alex Williamson Link: https://lore.kernel.org/r/20210817180500.1253-6-ameynarkhede03@gmail.com Signed-off-by: Alex Williamson Signed-off-by: Amey Narkhede Signed-off-by: Bjorn Helgaas Reviewed-by: Raphael Norwitz --- Documentation/ABI/testing/sysfs-bus-pci | 17 +++++ drivers/pci/pci-sysfs.c | 1 + drivers/pci/pci.c | 122 ++++++++++++++++++++++++++++++++ drivers/pci/pci.h | 2 + 4 files changed, 142 insertions(+) (limited to 'drivers/pci/pci-sysfs.c') diff --git a/Documentation/ABI/testing/sysfs-bus-pci b/Documentation/ABI/testing/sysfs-bus-pci index 793cbb76cd25..d4ae03296861 100644 --- a/Documentation/ABI/testing/sysfs-bus-pci +++ b/Documentation/ABI/testing/sysfs-bus-pci @@ -121,6 +121,23 @@ Description: child buses, and re-discover devices removed earlier from this part of the device tree. +What: /sys/bus/pci/devices/.../reset_method +Date: August 2021 +Contact: Amey Narkhede +Description: + Some devices allow an individual function to be reset + without affecting other functions in the same slot. + + For devices that have this support, a file named + reset_method is present in sysfs. Reading this file + gives names of the supported and enabled reset methods and + their ordering. Writing a space-separated list of names of + reset methods sets the reset methods and ordering to be + used when resetting the device. Writing an empty string + disables the ability to reset the device. Writing + "default" enables all supported reset methods in the + default ordering. + What: /sys/bus/pci/devices/.../reset Date: July 2009 Contact: Michael S. Tsirkin diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c index a1d9b0e83615..2fd44c97b7ec 100644 --- a/drivers/pci/pci-sysfs.c +++ b/drivers/pci/pci-sysfs.c @@ -1491,6 +1491,7 @@ const struct attribute_group *pci_dev_groups[] = { &pci_dev_config_attr_group, &pci_dev_rom_attr_group, &pci_dev_reset_attr_group, + &pci_dev_reset_method_attr_group, &pci_dev_vpd_attr_group, #ifdef CONFIG_DMI &pci_dev_smbios_attr_group, diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index 5ead8826c702..6da5f6d87f6a 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5132,6 +5132,128 @@ static const struct pci_reset_fn_method pci_reset_fn_methods[] = { { pci_reset_bus_function, .name = "bus" }, }; +static ssize_t reset_method_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct pci_dev *pdev = to_pci_dev(dev); + ssize_t len = 0; + int i, m; + + for (i = 0; i < PCI_NUM_RESET_METHODS; i++) { + m = pdev->reset_methods[i]; + if (!m) + break; + + len += sysfs_emit_at(buf, len, "%s%s", len ? " " : "", + pci_reset_fn_methods[m].name); + } + + if (len) + len += sysfs_emit_at(buf, len, "\n"); + + return len; +} + +static int reset_method_lookup(const char *name) +{ + int m; + + for (m = 1; m < PCI_NUM_RESET_METHODS; m++) { + if (sysfs_streq(name, pci_reset_fn_methods[m].name)) + return m; + } + + return 0; /* not found */ +} + +static ssize_t reset_method_store(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct pci_dev *pdev = to_pci_dev(dev); + char *options, *name; + int m, n; + u8 reset_methods[PCI_NUM_RESET_METHODS] = { 0 }; + + if (sysfs_streq(buf, "")) { + pdev->reset_methods[0] = 0; + pci_warn(pdev, "All device reset methods disabled by user"); + return count; + } + + if (sysfs_streq(buf, "default")) { + pci_init_reset_methods(pdev); + return count; + } + + options = kstrndup(buf, count, GFP_KERNEL); + if (!options) + return -ENOMEM; + + n = 0; + while ((name = strsep(&options, " ")) != NULL) { + if (sysfs_streq(name, "")) + continue; + + name = strim(name); + + m = reset_method_lookup(name); + if (!m) { + pci_err(pdev, "Invalid reset method '%s'", name); + goto error; + } + + if (pci_reset_fn_methods[m].reset_fn(pdev, 1)) { + pci_err(pdev, "Unsupported reset method '%s'", name); + goto error; + } + + if (n == PCI_NUM_RESET_METHODS - 1) { + pci_err(pdev, "Too many reset methods\n"); + goto error; + } + + reset_methods[n++] = m; + } + + reset_methods[n] = 0; + + /* Warn if dev-specific supported but not highest priority */ + if (pci_reset_fn_methods[1].reset_fn(pdev, 1) == 0 && + reset_methods[0] != 1) + pci_warn(pdev, "Device-specific reset disabled/de-prioritized by user"); + memcpy(pdev->reset_methods, reset_methods, sizeof(pdev->reset_methods)); + kfree(options); + return count; + +error: + /* Leave previous methods unchanged */ + kfree(options); + return -EINVAL; +} +static DEVICE_ATTR_RW(reset_method); + +static struct attribute *pci_dev_reset_method_attrs[] = { + &dev_attr_reset_method.attr, + NULL, +}; + +static umode_t pci_dev_reset_method_attr_is_visible(struct kobject *kobj, + struct attribute *a, int n) +{ + struct pci_dev *pdev = to_pci_dev(kobj_to_dev(kobj)); + + if (!pci_reset_supported(pdev)) + return 0; + + return a->mode; +} + +const struct attribute_group pci_dev_reset_method_attr_group = { + .attrs = pci_dev_reset_method_attrs, + .is_visible = pci_dev_reset_method_attr_is_visible, +}; + /** * __pci_reset_function_locked - reset a PCI device function while holding * the @dev mutex lock. diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h index ebeacb3dbe1e..b31afd4669cc 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -718,4 +718,6 @@ static inline int pci_acpi_program_hp_params(struct pci_dev *dev) extern const struct attribute_group aspm_ctrl_attr_group; #endif +extern const struct attribute_group pci_dev_reset_method_attr_group; + #endif /* DRIVERS_PCI_H */ -- cgit v1.2.3