On Thu, Oct 30, 2008 at 01:32:17PM +0800, Sheng Yang wrote:
> Some PCI device implemented PCI Advanced Feature, which is also support
> Function Level Reset(FLR).
I think patches 3 and 4 go off in the wrong direction. Rather than have
one megafunction that knows how to reset all devices, we should have
something more like this:
int pci_execute_reset_function(pdev)
{
int res;
res = pcie_flr(pdev);
if (res != -ENOTTY)
return res;
res = pci_af_flr(pdev);
if (res != -ENOTTY)
return res;
if (pdev->driver && pdev->driver->reset)
res = pdev->driver->reset(pdev);
return res;
}
(Assuming we add a reset op to the pci_driver function).
It's a bit tricky in that we'd like to test early if a device supports
reset or not.
> Signed-off-by: Sheng Yang <sheng@xxxxxxxxxxxxxxx>
> ---
> drivers/pci/pci.c | 38 ++++++++++++++++++++++++++++++++++++--
> 1 files changed, 36 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> index 2077aee..c432473 100644
> --- a/drivers/pci/pci.c
> +++ b/drivers/pci/pci.c
> @@ -1752,6 +1752,7 @@ EXPORT_SYMBOL(pci_set_dma_seg_boundary);
> #endif
>
> #define PCI_RESET_FUNC_CAP_PCIE_FLR 0
> +#define PCI_RESET_FUNC_CAP_PCI_AF_FLR 1
> static int __pci_check_reset_function_cap(struct pci_dev *dev)
> {
> int cappos;
> @@ -1764,6 +1765,13 @@ static int __pci_check_reset_function_cap(struct pci_dev *dev)
> return PCI_RESET_FUNC_CAP_PCIE_FLR;
> }
>
> + cappos = pci_find_capability(dev, PCI_CAP_ID_AF);
> + if (cappos) {
> + pci_read_config_byte(dev, cappos + PCI_AF_CAP, (u8 *)&cap);
> + if ((cap & PCI_AF_CAP_TP) && (cap & PCI_AF_CAP_FLR))
> + return PCI_RESET_FUNC_CAP_PCI_AF_FLR;
> + }
> +
> return -ENOTTY;
> }
>
> @@ -1798,7 +1806,8 @@ int pci_execute_reset_function(struct pci_dev *dev)
> r = 0;
> pci_block_user_cfg_access(dev);
>
> - if (reset_cap == PCI_RESET_FUNC_CAP_PCIE_FLR) {
> + switch (reset_cap) {
> + case PCI_RESET_FUNC_CAP_PCIE_FLR:
> /* Wait for Transaction Pending bit clean */
> msleep(100);
> cappos = pci_find_capability(dev, PCI_CAP_ID_EXP);
> @@ -1816,8 +1825,33 @@ int pci_execute_reset_function(struct pci_dev *dev)
> pci_write_config_word(dev, cappos + PCI_EXP_DEVCTL,
> PCI_EXP_DEVCTL_BCR_FLR);
> mdelay(100);
> - } else
> + break;
> +
> + case PCI_RESET_FUNC_CAP_PCI_AF_FLR:
> + /* Wait for Transaction Pending bit clean */
> + msleep(100);
> + cappos = pci_find_capability(dev, PCI_CAP_ID_AF);
> + pci_read_config_byte(dev, cappos + PCI_AF_STATUS,
> + (u8 *)&status);
> + if (status & PCI_AF_STATUS_TP) {
> + dev_info(&dev->dev, "Busy after 100ms while trying to"
> + " reset; sleeping for 1 second\n");
> + ssleep(1);
> + pci_read_config_byte(dev,
> + cappos + PCI_AF_STATUS, (u8 *)&status);
> + if (status & PCI_AF_STATUS_TP)
> + dev_info(&dev->dev, "Still busy after 1s; "
> + "proceeding with reset anyway\n");
> + }
> + pci_write_config_byte(dev, cappos + PCI_AF_CTRL,
> + PCI_AF_CTRL_FLR);
> + mdelay(100);
> + break;
> +
> + default:
> r = -ENOTTY;
> + break;
> + }
>
> pci_unblock_user_cfg_access(dev);
> return r;
> --
> 1.5.4.5
>
> --
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--
Matthew Wilcox Intel Open Source Technology Centre
"Bill, look, we understand that you're interested in selling us this
operating system, but compare it to ours. We can't possibly take such
a retrograde step."
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