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Message-Id: <20210817180500.1253-4-ameynarkhede03@gmail.com>
Date: Tue, 17 Aug 2021 23:34:54 +0530
From: Amey Narkhede <ameynarkhede03@...il.com>
To: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: alex.williamson@...hat.com,
Raphael Norwitz <raphael.norwitz@...anix.com>,
linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
kw@...ux.com, Shanker Donthineni <sdonthineni@...dia.com>,
Sinan Kaya <okaya@...nel.org>, Len Brown <lenb@...nel.org>,
"Rafael J . Wysocki" <rjw@...ysocki.net>,
Amey Narkhede <ameynarkhede03@...il.com>
Subject: [PATCH v16 3/9] 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.
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>
Reviewed-by: Raphael Norwitz <raphael.norwitz@...anix.com>
---
drivers/pci/pci.c | 95 ++++++++++++++++++++++++++-------------------
drivers/pci/pci.h | 8 +++-
drivers/pci/probe.c | 5 +--
include/linux/pci.h | 7 ++++
4 files changed, 71 insertions(+), 44 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 7d1d96711..67eab3d29 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -73,6 +73,11 @@ static void pci_dev_d3_sleep(struct pci_dev *dev)
msleep(delay);
}
+bool pci_reset_supported(struct pci_dev *dev)
+{
+ return dev->reset_methods[0] != 0;
+}
+
#ifdef CONFIG_PCI_DOMAINS
int pci_domains_supported = 1;
#endif
@@ -5117,6 +5122,16 @@ static void pci_dev_restore(struct pci_dev *dev)
err_handler->reset_done(dev);
}
+/* dev->reset_methods[] is a 0-terminated list of indices into this array */
+static const struct pci_reset_fn_method pci_reset_fn_methods[] = {
+ { },
+ { pci_dev_specific_reset, .name = "device_specific" },
+ { pcie_reset_flr, .name = "flr" },
+ { pci_af_flr, .name = "af_flr" },
+ { pci_pm_reset, .name = "pm" },
+ { pci_reset_bus_function, .name = "bus" },
+};
+
/**
* __pci_reset_function_locked - reset a PCI device function while holding
* the @dev mutex lock.
@@ -5139,65 +5154,65 @@ static void pci_dev_restore(struct pci_dev *dev)
*/
int __pci_reset_function_locked(struct pci_dev *dev)
{
- int rc;
+ int i, m, rc = -ENOTTY;
might_sleep();
/*
- * A reset method returns -ENOTTY if it doesn't support this device
- * and we should try the next method.
+ * 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.
+ * 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 (i = 0; i < PCI_NUM_RESET_METHODS; i++) {
+ m = dev->reset_methods[i];
+ if (!m)
+ return -ENOTTY;
+
+ rc = pci_reset_fn_methods[m].reset_fn(dev, 0);
+ if (!rc)
+ return 0;
+ if (rc != -ENOTTY)
+ return rc;
+ }
+
+ return -ENOTTY;
}
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.
+ * other functions in the same device. The PCI device must be in D0-D3hot
+ * state.
*
- * 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 m, i, rc;
+
+ BUILD_BUG_ON(ARRAY_SIZE(pci_reset_fn_methods) != PCI_NUM_RESET_METHODS);
might_sleep();
- 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;
+ i = 0;
+
+ for (m = 1; m < PCI_NUM_RESET_METHODS; m++) {
+ rc = pci_reset_fn_methods[m].reset_fn(dev, 1);
+ if (!rc)
+ dev->reset_methods[i++] = m;
+ else if (rc != -ENOTTY)
+ break;
+ }
- return pci_reset_bus_function(dev, 1);
+ dev->reset_methods[i] = 0;
}
/**
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 37c913bbc..743895374 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -33,7 +33,8 @@ 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);
+bool pci_reset_supported(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);
@@ -606,6 +607,11 @@ struct pci_dev_reset_methods {
int (*reset)(struct pci_dev *dev, int probe);
};
+struct pci_reset_fn_method {
+ int (*reset_fn)(struct pci_dev *pdev, int probe);
+ char *name;
+};
+
#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 df3f9db6e..5d8ad230f 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2405,9 +2405,8 @@ 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 aa85e7d31..d1a9a232d 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -49,6 +49,9 @@
PCI_STATUS_SIG_TARGET_ABORT | \
PCI_STATUS_PARITY)
+/* Number of reset methods used in pci_reset_fn_methods array in pci.c */
+#define PCI_NUM_RESET_METHODS 6
+
/*
* The PCI interface treats multi-function devices as independent
* devices. The slot/function address of each device is encoded
@@ -506,6 +509,10 @@ 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_NUM_RESET_METHODS]; /* Reset methods ordered by priority */
};
static inline struct pci_dev *pci_physfn(struct pci_dev *dev)
--
2.32.0
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