| Message ID | 20240613115032.29098-11-pstanner@redhat.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Make PCI's devres API more consistent | expand |
On Thu, Jun 13, 2024 at 01:50:23PM +0200, Philipp Stanner wrote: > 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 As pci_intx() is an outdated function, pcim_intx() shall not be made 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 drivers via a public API. What makes pci_intx() outdated? If it's outdated, we should mention why and what the 30+ callers (including a couple in drivers/pci/) should use instead. Bjorn
On Thu, 2024-06-13 at 16:06 -0500, Bjorn Helgaas wrote: > On Thu, Jun 13, 2024 at 01:50:23PM +0200, Philipp Stanner wrote: > > 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 As pci_intx() is an outdated function, pcim_intx() shall not be 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 drivers via a public API. > > What makes pci_intx() outdated? If it's outdated, we should mention > why and what the 30+ callers (including a couple in drivers/pci/) > should use instead. That is 100% based on Andy Shevchenko's (+CC) statement back from January 2024 a.D. [1] Apparently INTx is "old IRQ management" and should be done through pci_alloc_irq_vectors() nowadays. [1] https://lore.kernel.org/all/ZabyY3csP0y-p7lb@surfacebook.localdomain/ P. > > Bjorn >
On Fri, Jun 14, 2024 at 10:09:46AM +0200, Philipp Stanner wrote: > On Thu, 2024-06-13 at 16:06 -0500, Bjorn Helgaas wrote: > > On Thu, Jun 13, 2024 at 01:50:23PM +0200, Philipp Stanner wrote: > > > 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 drivers via a public API. > > > > What makes pci_intx() outdated? If it's outdated, we should mention > > why and what the 30+ callers (including a couple in drivers/pci/) > > should use instead. > > That is 100% based on Andy Shevchenko's (+CC) statement back from > January 2024 a.D. [1] > > Apparently INTx is "old IRQ management" and should be done through > pci_alloc_irq_vectors() nowadays. Do we have pcim_ support for pci_alloc_irq_vectors()? > [1] https://lore.kernel.org/all/ZabyY3csP0y-p7lb@surfacebook.localdomain/
On Fri, 2024-06-14 at 11:14 -0500, Bjorn Helgaas wrote: > On Fri, Jun 14, 2024 at 10:09:46AM +0200, Philipp Stanner wrote: > > On Thu, 2024-06-13 at 16:06 -0500, Bjorn Helgaas wrote: > > > On Thu, Jun 13, 2024 at 01:50:23PM +0200, Philipp Stanner wrote: > > > > 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 drivers via a public API. > > > > > > What makes pci_intx() outdated? If it's outdated, we should > > > mention > > > why and what the 30+ callers (including a couple in drivers/pci/) > > > should use instead. > > > > That is 100% based on Andy Shevchenko's (+CC) statement back from > > January 2024 a.D. [1] > > > > Apparently INTx is "old IRQ management" and should be done through > > pci_alloc_irq_vectors() nowadays. > > Do we have pcim_ support for pci_alloc_irq_vectors()? Nope. All PCI devres functions that exist are now in pci/devres.c, except for the hybrid functions (pci_intx() and everything calling __pci_request_region()) in pci.c P. > > > [1] > > https://lore.kernel.org/all/ZabyY3csP0y-p7lb@surfacebook.localdomain/ >
On Mon, Jun 17, 2024 at 10:21:10AM +0200, Philipp Stanner wrote: > On Fri, 2024-06-14 at 11:14 -0500, Bjorn Helgaas wrote: > > On Fri, Jun 14, 2024 at 10:09:46AM +0200, Philipp Stanner wrote: > ... > > > Apparently INTx is "old IRQ management" and should be done through > > > pci_alloc_irq_vectors() nowadays. > > > > Do we have pcim_ support for pci_alloc_irq_vectors()? > > Nope. Should we? Or is IRQ support not amenable to devm? Happened to see this new driver: https://lore.kernel.org/all/20240617100359.2550541-3-Basavaraj.Natikar@amd.com/ that uses devm and the only PCI-related part of .remove() is cleaning up the IRQs.
On Mon, 2024-06-17 at 11:46 -0500, Bjorn Helgaas wrote: > On Mon, Jun 17, 2024 at 10:21:10AM +0200, Philipp Stanner wrote: > > On Fri, 2024-06-14 at 11:14 -0500, Bjorn Helgaas wrote: > > > On Fri, Jun 14, 2024 at 10:09:46AM +0200, Philipp Stanner wrote: > > ... > > > > > Apparently INTx is "old IRQ management" and should be done > > > > through > > > > pci_alloc_irq_vectors() nowadays. > > > > > > Do we have pcim_ support for pci_alloc_irq_vectors()? > > > > Nope. > > Should we? Or is IRQ support not amenable to devm? I don't see why it wouldn't work, AFAIU you just register a callback that deregisters the interrupts again. This series here, though, stems from me trying to clean up drivers in DRM. That's when I discovered that regions / IO-mappings (which I need) are broken. Adding further stuff to pci/devres.c is no problem at all and independent from this series; one just has to add the code and call the appropriate devm_ functions. > > Happened to see this new driver: > https://lore.kernel.org/all/20240617100359.2550541-3-Basavaraj.Natikar@amd.com/ > that uses devm and the only PCI-related part of .remove() is cleaning > up the IRQs. > OK. They also use pcim_iomap_table() and stuff. I think we should inform about the deprecation. I don't have a user for IRQ at hand for my DRM work right now. I'd try to upstream new infrastructure we need there as I did for vboxvideo. Grüße, P.
diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c index e8de93e95eb6..7b72c952a9e5 100644 --- a/drivers/pci/devres.c +++ b/drivers/pci/devres.c @@ -42,6 +42,11 @@ 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, @@ -397,32 +402,75 @@ int pcim_set_mwi(struct pci_dev *pdev) } EXPORT_SYMBOL(pcim_set_mwi); + static inline bool mask_contains_bar(int mask, int bar) { return mask & BIT(bar); } -static void pcim_release(struct device *gendev, void *res) +static void pcim_intx_restore(struct device *dev, void *data) { - struct pci_dev *dev = to_pci_dev(gendev); - struct pci_devres *this = res; + struct pci_dev *pdev = to_pci_dev(dev); + struct pcim_intx_devres *res = data; - if (this->restore_intx) - pci_intx(dev, this->orig_intx); + pci_intx(pdev, res->orig_intx); +} - if (pci_is_enabled(dev) && !dev->pinned) - pci_disable_device(dev); +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; } -/* - * 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 (pci_is_enabled(dev) && !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 db2cc48f3d63..1b4832a60047 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -4443,6 +4443,16 @@ 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) @@ -4450,17 +4460,8 @@ 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 c355bb6a698d..9e87528f1157 100644 --- a/drivers/pci/pci.h +++ b/drivers/pci/pci.h @@ -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, const char *name);
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 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 now surplus function find_pci_dr(). Signed-off-by: Philipp Stanner <pstanner@redhat.com> --- drivers/pci/devres.c | 76 ++++++++++++++++++++++++++++++++++++-------- drivers/pci/pci.c | 21 ++++++------ drivers/pci/pci.h | 13 ++++---- 3 files changed, 80 insertions(+), 30 deletions(-)