[PATCH v4 10/21] powerpc/powernv: Fundamental reset for PCI bus reset

[Gavin Shan]

On Mon, May 11, 2015 at 05:17:42PM +1000, Alexey Kardashevskiy wrote:
>On 05/11/2015 04:47 PM, Gavin Shan wrote:
>>On Sun, May 10, 2015 at 12:12:18AM +1000, Alexey Kardashevskiy wrote:
>>>On 05/01/2015 04:02 PM, Gavin Shan wrote:
>>>>Function pnv_pci_reset_secondary_bus() is used to reset specified
>>>>PCI bus, which is leaded by root complex or PCI bridge. That means
>>>>the function shouldn't be called on PCI root bus and the patch
>>>>removes the logic for that case.
>>>>
>>>>Also, some adapters beneath the indicated PCI bus may require
>>>>fundamental reset in order to successfully reload their firmwares
>>>>after the reset. The patch translates hot reset to fundamental reset
>>>>for that case.
>>>>
>>>>Signed-off-by: Gavin Shan <gwshan at linux.vnet.ibm.com>
>>>>---
>>>>  arch/powerpc/platforms/powernv/eeh-powernv.c | 35 +++++++++++++++++++++-------
>>>>  1 file changed, 26 insertions(+), 9 deletions(-)
>>>>
>>>>diff --git a/arch/powerpc/platforms/powernv/eeh-powernv.c b/arch/powerpc/platforms/powernv/eeh-powernv.c
>>>>index 3c01095..58e4dcf 100644
>>>>--- a/arch/powerpc/platforms/powernv/eeh-powernv.c
>>>>+++ b/arch/powerpc/platforms/powernv/eeh-powernv.c
>>>>@@ -888,18 +888,35 @@ static int pnv_eeh_bridge_reset(struct pci_dev *dev, int option)
>>>>  	return (rc == OPAL_SUCCESS) ? 0 : -EIO;
>>>>  }
>>>>
>>>>-void pnv_pci_reset_secondary_bus(struct pci_dev *dev)
>>>
>>>
>>>Why changing dev to pdev? Keeping "dev" could make the patch simpler.
>>>
>>
>>In the early stage when I wrote the EEH code, I had "dev" to refer PCI
>>device, which isn't precisely enough. Actually, "dev" means "struct device"
>>while "pdev" stands for "struct pci_dev". That's why I changed it.
>
>
>The rest of the file and the kernel overall use "dev" for pci_dev just fine.
>I would not bother.
>

Ok. I'll keep it.

>>>>+static int pnv_pci_dev_reset_type(struct pci_dev *pdev, void *data)
>>>>  {
>>>>-	struct pci_controller *hose;
>>>>+	int *freset = data;
>>>>
>>>>-	if (pci_is_root_bus(dev->bus)) {
>>>>-		hose = pci_bus_to_host(dev->bus);
>>>>-		pnv_eeh_phb_reset(hose, EEH_RESET_HOT);
>>>>-		pnv_eeh_phb_reset(hose, EEH_RESET_DEACTIVATE);
>>>>-	} else {
>>>>-		pnv_eeh_bridge_reset(dev, EEH_RESET_HOT);
>>>>-		pnv_eeh_bridge_reset(dev, EEH_RESET_DEACTIVATE);
>>>>+	/*
>>>>+	 * Stop the iteration immediately if there is any
>>>>+	 * one PCI device requesting fundamental reset
>>>>+	 */
>>>>+	*freset |= pdev->needs_freset;
>>>>+	return *freset;
>>>>+}
>>>>+
>>>>+void pnv_pci_reset_secondary_bus(struct pci_dev *pdev)
>>>>+{
>>>>+	int option = EEH_RESET_HOT;
>>>>+	int freset = 0;
>>>>+
>>>>+	/* Check if there're any PCI devices asking for fundamental reset */
>>>>+	if (pdev->subordinate) {
>>>>+		pci_walk_bus(pdev->subordinate,
>>>>+			     pnv_pci_dev_reset_type,
>>>>+			     &freset);
>>>>+		if (freset)
>>>>+			option = EEH_RESET_FUNDAMENTAL;
>>>>  	}
>>>>+
>>>>+	/* Issue the requested type of reset */
>>>>+	pnv_eeh_bridge_reset(pdev, option);
>>>>+	pnv_eeh_bridge_reset(pdev, EEH_RESET_DEACTIVATE);
>>>>  }
>>>>
>>>>  /**
>>>>

Thanks,
Gavin