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Message-ID: <6cd568a9-1332-5a47-bdb2-ea079a8462af@linux.intel.com>
Date: Thu, 13 Jun 2024 20:23:26 +0300 (EEST)
From: Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
To: Philipp Stanner <pstanner@...hat.com>
cc: Hans de Goede <hdegoede@...hat.com>,
Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
Maxime Ripard <mripard@...nel.org>,
Thomas Zimmermann <tzimmermann@...e.de>, David Airlie <airlied@...il.com>,
Daniel Vetter <daniel@...ll.ch>, Bjorn Helgaas <bhelgaas@...gle.com>,
Sam Ravnborg <sam@...nborg.org>, dakr@...hat.com,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
linux-pci@...r.kernel.org
Subject: Re: [PATCH v7 10/13] PCI: Give pci(m)_intx its own devres callback
On Wed, 5 Jun 2024, 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 As pci_intx() is an outdated function, pcim_intx() shall not be made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.
>
> Implement pcim_intx() with its own device resource.
> Make pci_intx() call pcim_intx() in the managed case.
>
> Signed-off-by: Philipp Stanner <pstanner@...hat.com>
> ---
> drivers/pci/devres.c | 76 ++++++++++++++++++++++++++++++++++++--------
> drivers/pci/pci.c | 23 ++++++++------
> drivers/pci/pci.h | 7 ++--
> 3 files changed, 80 insertions(+), 26 deletions(-)
>
> diff --git a/drivers/pci/devres.c b/drivers/pci/devres.c
> index 0bafb67e1886..9a997de280df 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. */
INTx
> +struct pcim_intx_devres {
> + int orig_intx;
> +};
> +
> enum pcim_addr_devres_type {
> /* Default initializer. */
> PCIM_ADDR_DEVRES_TYPE_INVALID,
> @@ -392,32 +397,75 @@ int pcim_set_mwi(struct pci_dev *pdev)
> }
> EXPORT_SYMBOL(pcim_set_mwi);
>
> +
> static inline bool mask_contains_bar(int mask, int bar)
Stray change.
--
i.
> {
> 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 (!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 (!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 04accdfab7ce..de58e77f0ee0 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -4444,11 +4444,23 @@ void pci_disable_parity(struct pci_dev *dev)
> * 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!
> + *
> + * 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)
> @@ -4456,17 +4468,8 @@ 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 dbf6772aaaaf..3aa57cd8b3e5 100644
> --- a/drivers/pci/pci.h
> +++ b/drivers/pci/pci.h
> @@ -823,11 +823,14 @@ static inline pci_power_t mid_pci_get_power_state(struct pci_dev *pdev)
> * 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);
>
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