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PCI: Add managed pcim_intx()

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pci_intx() is a "hybrid" function, i.e., it is managed if
pcim_enable_device() has been called, but unmanaged otherwise.

Add pcim_intx(), which is always managed, and implement pci_intx() using
it.

Remove the now-unused struct pci_devres.orig_intx and .restore_intx and
find_pci_dr().

Link: https://lore.kernel.org/r/20240613115032.29098-11-pstanner@redhat.com
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
[kwilczynski: squashed in
https://lore.kernel.org/r/426645d40776198e0fcc942f4a6cac4433c7a9aa.camel@redhat.com
to fix problem reported and tested by Ashish Kalra <Ashish.Kalra@amd.com>:
https://lore.kernel.org/r/20240708214656.4721-1-Ashish.Kalra@amd.com
https://lore.kernel.org/r/8c4634e9-4f02-4c54-9c89-d75e2f4bf026@amd.com/]
Signed-off-by: Krzysztof Wilczyński <kwilczynski@kernel.org>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Philipp Stanner 2024-06-13 13:50:23 +02:00 committed by Bjorn Helgaas
parent 2c3e842f12
commit 25216afc9d
3 changed files with 86 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

86
drivers/pci/devres.c
View File

@ -43,6 +43,11 @@ 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,
@ -406,29 +411,80 @@ static inline bool mask_contains_bar(int mask, int bar)
return mask & BIT(bar);
}
/*
* This is a copy of pci_intx() used to bypass the problem of recursive
* function calls due to the hybrid nature of pci_intx().
*/
static void __pcim_intx(struct pci_dev *pdev, int enable)
{
u16 pci_command, new;
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);
}
static void pcim_intx_restore(struct device *dev, void *data)
{
struct pci_dev *pdev = to_pci_dev(dev);
struct pcim_intx_devres *res = data;
__pcim_intx(pdev, res->orig_intx);
}
static struct pcim_intx_devres *get_or_create_intx_devres(struct device *dev)
{
struct pcim_intx_devres *res;
res = devres_find(dev, pcim_intx_restore, NULL, NULL);
if (res)
return res;
res = devres_alloc(pcim_intx_restore, sizeof(*res), GFP_KERNEL);
if (res)
devres_add(dev, res);
return res;
}
/**
* 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.
*
* Enable/disable PCI INTx for device @pdev.
* Restore the original state on driver detach.
*/
int pcim_intx(struct pci_dev *pdev, int enable)
{
struct pcim_intx_devres *res;
res = get_or_create_intx_devres(&pdev->dev);
if (!res)
return -ENOMEM;
res->orig_intx = !enable;
__pcim_intx(pdev, enable);
return 0;
}
static void pcim_release(struct device *gendev, void *res)
{
struct pci_dev *dev = to_pci_dev(gendev);
struct pci_devres *this = res;
if (this->restore_intx)
pci_intx(dev, this->orig_intx);
if (pci_is_enabled(dev) && !dev->pinned)
pci_disable_device(dev);
}
/*
* TODO: After the last four callers in pci.c are ported, find_pci_dr()
* needs to be made static again.
*/
struct pci_devres *find_pci_dr(struct pci_dev *pdev)
{
if (pci_is_managed(pdev))
return devres_find(&pdev->dev, pcim_release, NULL, NULL);
return NULL;
}
static struct pci_devres *get_pci_dr(struct pci_dev *pdev)
{
struct pci_devres *dr, *new_dr;

19
drivers/pci/pci.c
View File

@ -4442,12 +4442,18 @@ void pci_disable_parity(struct pci_dev *dev)
* NOTE:
* This is a "hybrid" function: It's normally unmanaged, but becomes managed
* when pcim_enable_device() has been called in advance. This hybrid feature is
* DEPRECATED!
* DEPRECATED! If you want managed cleanup, use pcim_intx() instead.
*/
void pci_intx(struct pci_dev *pdev, int enable)
{
u16 pci_command, new;
/* Preserve the "hybrid" behavior for backwards compatibility */
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)
@ -4455,17 +4461,8 @@ 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);

13
drivers/pci/pci.h
View File

@ -816,16 +816,17 @@ static inline pci_power_t mid_pci_get_power_state(struct pci_dev *pdev)
* 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.
* TODO: Struct pci_devres only needs 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;
/*
* TODO:
* This struct is now surplus. Remove it by refactoring pci/devres.c
*/
};
struct pci_devres *find_pci_dr(struct pci_dev *pdev);
int pcim_intx(struct pci_dev *dev, int enable);
int pcim_request_region(struct pci_dev *pdev, int bar, const char *name);
int pcim_request_region_exclusive(struct pci_dev *pdev, int bar,