[PATCH v6 08/10] PCI: Give pci(m)_intx its own devres callback

Philipp Stanner
2024-04-08T08:44:49Z

pci_intx() is one of the functions that have "hybrid mode" (i.e.,
sometimes managed, sometimes not). Providing a separate pcim_intx()
function with its own device resource and cleanup callback allows for
removing further large parts of the legacy pci-devres implementation.

As in the region-request-functions, pci_intx() has to call into its
managed counterpart for backwards compatibility.

As pci_intx() is an outdated function, pcim_intx() shall not be made
visible to other drivers via a public API.

Implement pcim_intx() with its own device resource.
Make pci_intx() call pcim_intx() in the managed case.
Remove the struct pci_devres from pci.h.

Signed-off-by: Philipp Stanner <pstanner@redhat.com>
---
drivers/pci/devres.c | 74 +++++++++++++++++++++++++++++++++++---------
drivers/pci/pci.c | 24 +++++++-------
drivers/pci/pci.h | 17 +---------
3 files changed, 74 insertions(+), 41 deletions(-)

diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
index e257c212cd9c..b81bbb9abe51 100644
--- a/drivers/pci/devres.c
+++ b/drivers/pci/devres.c
@@ -40,6 +40,11 @@ struct pcim_iomap_devres {
void __iomem *table[PCI_STD_NUM_BARS];
};

+/* Used to restore the old intx state on driver detach. */
+struct pcim_intx_devres {
+ int orig_intx;
+};
+
enum pcim_addr_devres_type {
/* Default initializer. */
PCIM_ADDR_DEVRES_TYPE_INVALID,
@@ -401,28 +406,69 @@ int pcim_set_mwi(struct pci_dev *pdev)
}
EXPORT_SYMBOL(pcim_set_mwi);

+static void pcim_intx_restore(struct device *dev, void *data)
+{
+ struct pci_dev *pdev = to_pci_dev(dev);
+ struct pcim_intx_devres *res = data;

-static void pcim_release(struct device *gendev, void *res)
+ pci_intx(pdev, res->orig_intx);
+}
+
+static struct pcim_intx_devres *get_or_create_intx_devres(struct device *dev)
{
- struct pci_dev *dev = to_pci_dev(gendev);
- struct pci_devres *this = res;
+ struct pcim_intx_devres *res;

- if (this->restore_intx)
- pci_intx(dev, this->orig_intx);
+ res = devres_find(dev, pcim_intx_restore, NULL, NULL);
+ if (res)
+ return res;

- if (!dev->pinned)
- pci_disable_device(dev);
+ res = devres_alloc(pcim_intx_restore, sizeof(*res), GFP_KERNEL);
+ if (res)
+ devres_add(dev, res);
+
+ return res;
}

-/*
- * TODO: After the last four callers in pci.c are ported, find_pci_dr()
- * needs to be made static again.
+/**
+ * pcim_intx - managed pci_intx()
+ * @pdev: the PCI device to operate on
+ * @enable: boolean: whether to enable or disable PCI INTx
+ *
+ * Returns: 0 on success, -ENOMEM on error.
+ *
+ * Enables/disables PCI INTx for device @pdev.
+ * Restores the original state on driver detach.
*/
-struct pci_devres *find_pci_dr(struct pci_dev *pdev)
+int pcim_intx(struct pci_dev *pdev, int enable)
{
- if (pci_is_managed(pdev))
- return devres_find(&pdev->dev, pcim_release, NULL, NULL);
- return NULL;
+ u16 pci_command, new;
+ struct pcim_intx_devres *res;
+
+ res = get_or_create_intx_devres(&pdev->dev);
+ if (!res)
+ return -ENOMEM;
+
+ res->orig_intx = !enable;
+
+ pci_read_config_word(pdev, PCI_COMMAND, &pci_command);
+
+ if (enable)
+ new = pci_command & ~PCI_COMMAND_INTX_DISABLE;
+ else
+ new = pci_command | PCI_COMMAND_INTX_DISABLE;
+
+ if (new != pci_command)
+ pci_write_config_word(pdev, PCI_COMMAND, new);
+
+ return 0;
+}
+
+static void pcim_release(struct device *gendev, void *res)
+{
+ struct pci_dev *dev = to_pci_dev(gendev);
+
+ if (!dev->pinned)
+ pci_disable_device(dev);
}

static struct pci_devres *get_pci_dr(struct pci_dev *pdev)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 9f1419bac9b9..f59dbad69452 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3873,7 +3873,7 @@ EXPORT_SYMBOL(pci_enable_atomic_ops_to_root);
void pci_release_region(struct pci_dev *pdev, int bar)
{
/*
- * This is done for backwards compatibility, because the old pci-devres
+ * This is done for backwards compatibility, because the old PCI devres
* API had a mode in which the function became managed if it had been
* enabled with pcim_enable_device() instead of pci_enable_device().
*/
@@ -4461,11 +4461,22 @@ void pci_disable_parity(struct pci_dev *dev)
* This is a "hybrid" function: Its normally unmanaged, but becomes managed
* when pcim_enable_device() has been called in advance.
* This hybrid feature is DEPRECATED!
+ * Use pcim_intx() if you need a managed version.
*/
void pci_intx(struct pci_dev *pdev, int enable)
{
u16 pci_command, new;

+ /*
+ * This is done for backwards compatibility, because the old PCI devres
+ * API had a mode in which this function became managed if the dev had
+ * been enabled with pcim_enable_device() instead of pci_enable_device().
+ */
+ if (pci_is_managed(pdev)) {
+ WARN_ON_ONCE(pcim_intx(pdev, enable) != 0);
+ return;
+ }
+
pci_read_config_word(pdev, PCI_COMMAND, &pci_command);

if (enable)
@@ -4473,17 +4484,8 @@ void pci_intx(struct pci_dev *pdev, int enable)
else
new = pci_command | PCI_COMMAND_INTX_DISABLE;

- if (new != pci_command) {
- struct pci_devres *dr;
-
+ if (new != pci_command)
pci_write_config_word(pdev, PCI_COMMAND, new);
-
- dr = find_pci_dr(pdev);
- if (dr && !dr->restore_intx) {
- dr->restore_intx = 1;
- dr->orig_intx = !enable;
- }
- }
}
EXPORT_SYMBOL_GPL(pci_intx);

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index c98de280b16e..1ca591f37270 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -812,22 +812,7 @@ static inline pci_power_t mid_pci_get_power_state(struct pci_dev *pdev)
}
#endif

-/*
- * Managed PCI resources. This manages device on/off, INTx/MSI/MSI-X
- * on/off and BAR regions. pci_dev itself records MSI/MSI-X status, so
- * there's no need to track it separately. pci_devres is initialized
- * when a device is enabled using managed PCI device enable interface.
- *
- * TODO: Struct pci_devres and find_pci_dr() only need to be here because
- * they're used in pci.c. Port or move these functions to devres.c and
- * then remove them from here.
- */
-struct pci_devres {
- unsigned int orig_intx:1;
- unsigned int restore_intx:1;
-};
-
-struct pci_devres *find_pci_dr(struct pci_dev *pdev);
+int pcim_intx(struct pci_dev *dev, int enable);

/*
* Config Address for PCI Configuration Mechanism #1
--
2.44.0