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Message-Id: <20210519235426.99728-4-ameynarkhede03@gmail.com>
Date: Thu, 20 May 2021 05:24:22 +0530
From: Amey Narkhede <ameynarkhede03@...il.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: alex.williamson@...hat.com, raphael.norwitz@...anix.com,
linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
kw@...ux.com, Amey Narkhede <ameynarkhede03@...il.com>
Subject: [PATCH RESEND v2 3/7] PCI: Add new array for keeping track of ordering of reset methods
Introduce a new array reset_methods in struct pci_dev
to keep track of reset mechanisms supported by the
device and their ordering. Also refactor probing and reset
functions to take advantage of calling convention of reset
functions.
Reviewed-by: Alex Williamson <alex.williamson@...hat.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@...anix.com>
Co-developed-by: Alex Williamson <alex.williamson@...hat.com>
Signed-off-by: Alex Williamson <alex.williamson@...hat.com>
Signed-off-by: Amey Narkhede <ameynarkhede03@...il.com>
---
drivers/pci/pci.c | 107 ++++++++++++++++++++++++++------------------
drivers/pci/pci.h | 10 ++++-
drivers/pci/probe.c | 5 +--
include/linux/pci.h | 7 +++
4 files changed, 82 insertions(+), 47 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index b998d6ad3..ca46a55c7 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -72,6 +72,14 @@ static void pci_dev_d3_sleep(struct pci_dev *dev)
msleep(delay);
}
+bool pci_reset_supported(struct pci_dev *dev)
+{
+ u8 null_reset_methods[PCI_RESET_FN_METHODS] = { 0 };
+
+ return memcmp(null_reset_methods,
+ dev->reset_methods, PCI_RESET_FN_METHODS);
+}
+
#ifdef CONFIG_PCI_DOMAINS
int pci_domains_supported = 1;
#endif
@@ -5068,6 +5076,19 @@ static void pci_dev_restore(struct pci_dev *dev)
err_handler->reset_done(dev);
}
+/*
+ * The ordering for functions in pci_reset_fn_methods
+ * is required for reset_methods byte array defined
+ * in struct pci_dev
+ */
+const struct pci_reset_fn_method pci_reset_fn_methods[] = {
+ { .reset_fn = &pci_dev_specific_reset, .name = "device_specific" },
+ { .reset_fn = &pcie_reset_flr, .name = "flr" },
+ { .reset_fn = &pci_af_flr, .name = "af_flr" },
+ { .reset_fn = &pci_pm_reset, .name = "pm" },
+ { .reset_fn = &pci_reset_bus_function, .name = "bus" },
+};
+
/**
* __pci_reset_function_locked - reset a PCI device function while holding
* the @dev mutex lock.
@@ -5090,65 +5111,65 @@ static void pci_dev_restore(struct pci_dev *dev)
*/
int __pci_reset_function_locked(struct pci_dev *dev)
{
- int rc;
+ int i, rc = -ENOTTY;
+ u8 prio;
might_sleep();
- /*
- * A reset method returns -ENOTTY if it doesn't support this device
- * and we should try the next method.
- *
- * If it returns 0 (success), we're finished. If it returns any
- * other error, we're also finished: this indicates that further
- * reset mechanisms might be broken on the device.
- */
- rc = pci_dev_specific_reset(dev, 0);
- if (rc != -ENOTTY)
- return rc;
- rc = pcie_reset_flr(dev, 0);
- if (rc != -ENOTTY)
- return rc;
- rc = pci_af_flr(dev, 0);
- if (rc != -ENOTTY)
- return rc;
- rc = pci_pm_reset(dev, 0);
- if (rc != -ENOTTY)
- return rc;
- return pci_reset_bus_function(dev, 0);
+ for (prio = PCI_RESET_FN_METHODS; prio; prio--) {
+ for (i = 0; i < PCI_RESET_FN_METHODS; i++) {
+ if (dev->reset_methods[i] == prio) {
+ /*
+ * A reset method returns -ENOTTY if it doesn't support this device
+ * and we should try the next method.
+ *
+ * If it returns 0 (success), we're finished. If it returns any
+ * other error, we're also finished: this indicates that further
+ * reset mechanisms might be broken on the device.
+ */
+ rc = pci_reset_fn_methods[i].reset_fn(dev, 0);
+ if (rc != -ENOTTY)
+ return rc;
+ break;
+ }
+ }
+ if (i == PCI_RESET_FN_METHODS)
+ break;
+ }
+ return rc;
}
EXPORT_SYMBOL_GPL(__pci_reset_function_locked);
/**
- * pci_probe_reset_function - check whether the device can be safely reset
- * @dev: PCI device to reset
+ * pci_init_reset_methods - check whether device can be safely reset
+ * and store supported reset mechanisms.
+ * @dev: PCI device to check for reset mechanisms
*
* Some devices allow an individual function to be reset without affecting
* other functions in the same device. The PCI device must be responsive
- * to PCI config space in order to use this function.
+ * to reads and writes to its PCI config space in order to use this function.
*
- * Returns 0 if the device function can be reset or negative if the
- * device doesn't support resetting a single function.
+ * Stores reset mechanisms supported by device in reset_methods byte array
+ * which is a member of struct pci_dev
*/
-int pci_probe_reset_function(struct pci_dev *dev)
+void pci_init_reset_methods(struct pci_dev *dev)
{
- int rc;
+ int i, rc;
+ u8 prio = PCI_RESET_FN_METHODS;
+ u8 reset_methods[PCI_RESET_FN_METHODS] = { 0 };
- might_sleep();
+ BUILD_BUG_ON(ARRAY_SIZE(pci_reset_fn_methods) != PCI_RESET_FN_METHODS);
- rc = pci_dev_specific_reset(dev, 1);
- if (rc != -ENOTTY)
- return rc;
- rc = pcie_reset_flr(dev, 1);
- if (rc != -ENOTTY)
- return rc;
- rc = pci_af_flr(dev, 1);
- if (rc != -ENOTTY)
- return rc;
- rc = pci_pm_reset(dev, 1);
- if (rc != -ENOTTY)
- return rc;
+ might_sleep();
- return pci_reset_bus_function(dev, 1);
+ for (i = 0; i < PCI_RESET_FN_METHODS; i++) {
+ rc = pci_reset_fn_methods[i].reset_fn(dev, 1);
+ if (!rc)
+ reset_methods[i] = prio--;
+ else if (rc != -ENOTTY)
+ break;
+ }
+ memcpy(dev->reset_methods, reset_methods, sizeof(reset_methods));
}
/**
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index ef7c46613..61d09e4dd 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -39,7 +39,7 @@ enum pci_mmap_api {
int pci_mmap_fits(struct pci_dev *pdev, int resno, struct vm_area_struct *vmai,
enum pci_mmap_api mmap_api);
-int pci_probe_reset_function(struct pci_dev *dev);
+void pci_init_reset_methods(struct pci_dev *dev);
int pci_bridge_secondary_bus_reset(struct pci_dev *dev);
int pci_bus_error_reset(struct pci_dev *dev);
@@ -612,6 +612,14 @@ struct pci_dev_reset_methods {
int (*reset)(struct pci_dev *dev, int probe);
};
+typedef int (*pci_reset_fn_t)(struct pci_dev *, int);
+
+struct pci_reset_fn_method {
+ pci_reset_fn_t reset_fn;
+ char *name;
+};
+
+extern const struct pci_reset_fn_method pci_reset_fn_methods[];
#ifdef CONFIG_PCI_QUIRKS
int pci_dev_specific_reset(struct pci_dev *dev, int probe);
#else
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 953f15abc..c5cfdd239 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2403,9 +2403,8 @@ static void pci_init_capabilities(struct pci_dev *dev)
pci_rcec_init(dev); /* Root Complex Event Collector */
pcie_report_downtraining(dev);
-
- if (pci_probe_reset_function(dev) == 0)
- dev->reset_fn = 1;
+ pci_init_reset_methods(dev);
+ dev->reset_fn = pci_reset_supported(dev);
}
/*
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8d20e51ab..5c5925ecf 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -49,6 +49,8 @@
PCI_STATUS_SIG_TARGET_ABORT | \
PCI_STATUS_PARITY)
+#define PCI_RESET_FN_METHODS 5
+
/*
* The PCI interface treats multi-function devices as independent
* devices. The slot/function address of each device is encoded
@@ -506,6 +508,10 @@ struct pci_dev {
char *driver_override; /* Driver name to force a match */
unsigned long priv_flags; /* Private flags for the PCI driver */
+ /*
+ * See pci_reset_fn_methods array in pci.c for ordering
+ */
+ u8 reset_methods[PCI_RESET_FN_METHODS]; /* Array for storing ordering of reset methods */
};
static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
@@ -1219,6 +1225,7 @@ u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev,
void pcie_print_link_status(struct pci_dev *dev);
int pcie_reset_flr(struct pci_dev *dev, int probe);
int pcie_flr(struct pci_dev *dev);
+bool pci_reset_supported(struct pci_dev *dev);
int __pci_reset_function_locked(struct pci_dev *dev);
int pci_reset_function(struct pci_dev *dev);
int pci_reset_function_locked(struct pci_dev *dev);
--
2.31.1
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