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

[Gavin Shan <gwshan@linux.vnet.ibm.com>]

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@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.

>>+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