[U-Boot] [PATCH v2 2/9] dm: pci: Add a way to iterate through all PCI devices
Bin Meng
bmeng.cn at gmail.com
Mon Aug 10 08:18:46 CEST 2015
Hi Simon,
On Sat, Aug 8, 2015 at 10:26 PM, Simon Glass <sjg at chromium.org> wrote:
> These functions allow iteration through all PCI devices including bridges.
> The children of each PCI bus are returned in turn. This can be useful for
> configuring, checking or enumerating all the devices.
>
> Signed-off-by: Simon Glass <sjg at chromium.org>
> ---
>
> Changes in v2:
> - Add a comment as to why we need to scan multiple PCI controllers
>
> drivers/pci/pci-uclass.c | 62 ++++++++++++++++++++++++++++++++++++++++++++++++
> include/pci.h | 25 +++++++++++++++++++
> 2 files changed, 87 insertions(+)
>
> diff --git a/drivers/pci/pci-uclass.c b/drivers/pci/pci-uclass.c
> index b79927e..2d5a0c1 100644
> --- a/drivers/pci/pci-uclass.c
> +++ b/drivers/pci/pci-uclass.c
> @@ -775,6 +775,68 @@ static int pci_bridge_write_config(struct udevice *bus, pci_dev_t bdf,
> return pci_bus_write_config(hose->ctlr, bdf, offset, value, size);
> }
>
> +static int skip_to_next_device(struct udevice *bus, struct udevice **devp)
> +{
> + struct udevice *dev;
> + int ret = 0;
> +
> + /*
> + * Scan through all the PCI controllers. On x86 there will only be one
> + * but that is not necessarily true on other hardware.
> + */
> + do {
> + do {
> + device_find_first_child(bus, &dev);
> + if (dev) {
> + *devp = dev;
> + return 0;
> + }
> + } while (dev);
There is no need to do a 'do..while' here.
> + ret = uclass_next_device(&bus);
> + if (ret)
> + return ret;
> + } while (bus);
> +
> + return 0;
> +}
> +
> +int pci_find_next_device(struct udevice **devp)
> +{
> + struct udevice *child = *devp;
> + struct udevice *bus = child->parent;
> + int ret;
> +
> + /* First try all the siblings */
> + *devp = NULL;
> + while (child) {
> + device_find_next_child(&child);
> + if (child) {
> + *devp = child;
> + return 0;
> + }
> + }
> +
> + /* We ran out of siblings. Try the next bus */
> + ret = uclass_next_device(&bus);
> + if (ret)
> + return ret;
> +
> + return bus ? skip_to_next_device(bus, devp) : 0;
> +}
> +
> +int pci_find_first_device(struct udevice **devp)
> +{
> + struct udevice *bus;
> + int ret;
> +
> + *devp = NULL;
> + ret = uclass_first_device(UCLASS_PCI, &bus);
> + if (ret)
> + return ret;
> +
> + return skip_to_next_device(bus, devp);
> +}
> +
> UCLASS_DRIVER(pci) = {
> .id = UCLASS_PCI,
> .name = "pci",
> diff --git a/include/pci.h b/include/pci.h
> index d1e2765..488ff44 100644
> --- a/include/pci.h
> +++ b/include/pci.h
> @@ -910,6 +910,31 @@ int pci_bus_find_devfn(struct udevice *bus, pci_dev_t find_devfn,
> struct udevice **devp);
>
> /**
> + * pci_find_first_device() - return the first available PCI device
> + *
> + * This function and pci_find_first_device() allow iteration through all
> + * available PCI devices on all buses. Assuming there are any, this will
> + * return the first one.
> + *
> + * @devp: Set to the first available device, or NULL if no more are left
> + * or we got an error
> + * @return 0 if all is OK, -ve on error (e.g. a bus/bridge failed to probe)
> + */
> +int pci_find_first_device(struct udevice **devp);
> +
> +/**
> + * pci_find_next_device() - return the next available PCI device
> + *
> + * Finds the next available PCI device after the one supplied, or sets @devp
> + * to NULL if there are no more.
> + *
> + * @devp: On entry, the last device returned. Set to the next available
> + * device, or NULL if no more are left or we got an error
> + * @return 0 if all is OK, -ve on error (e.g. a bus/bridge failed to probe)
> + */
> +int pci_find_next_device(struct udevice **devp);
> +
> +/**
> * pci_get_ff() - Returns a mask for the given access size
> *
> * @size: Access size
> --
Regards,
Bin
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