Re: [PATCH] powerpc/kernel: Change retrieval of pci_dn
From: Sam Bobroff <hidden>
Date: 2017-08-29 06:20:42
On Mon, Aug 28, 2017 at 11:05:03AM -0500, Bryant G. Ly wrote:
For a PCI device it's pci_dn can be retrieved from pdev->dev.archdata.firmware_data, PCI_DN(devnode), or parent's list. Thus, we should just use the generic function pci_get_pdn_by_devfn to get the pci_dn. Signed-off-by: Bryant G. Ly <redacted>
Reviewed-by: Sam Bobroff <redacted>
I don't know this area but I tested it using a patched kernel with the
old and new code together. My test kernel booted fine (in QEMU+KVM) and
I saw 26 reads and 4 writes, all of which got the same value with either
code block.
I also checked that the error result in the "not found" case is the same
as well, which it is, because rtas_{read,write}_config() will return
PCIBIOS_DEVICE_NOT_FOUND if given a NULL pdn.
So, looks good to me.
Cheers,
Sam.
quoted hunk ↗ jump to hunk
--- arch/powerpc/kernel/rtas_pci.c | 30 ++---------------------------- 1 file changed, 2 insertions(+), 28 deletions(-)diff --git a/arch/powerpc/kernel/rtas_pci.c b/arch/powerpc/kernel/rtas_pci.c index 73f1934..c21e6c5 100644 --- a/arch/powerpc/kernel/rtas_pci.c +++ b/arch/powerpc/kernel/rtas_pci.c@@ -91,25 +91,13 @@ static int rtas_pci_read_config(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 *val) { - struct device_node *busdn, *dn; struct pci_dn *pdn; - bool found = false; int ret; /* Search only direct children of the bus */ *val = 0xFFFFFFFF; - busdn = pci_bus_to_OF_node(bus); - for (dn = busdn->child; dn; dn = dn->sibling) { - pdn = PCI_DN(dn); - if (pdn && pdn->devfn == devfn - && of_device_is_available(dn)) { - found = true; - break; - } - } - if (!found) - return PCIBIOS_DEVICE_NOT_FOUND; + pdn = pci_get_pdn_by_devfn(bus, devfn); ret = rtas_read_config(pdn, where, size, val); if (*val == EEH_IO_ERROR_VALUE(size) &&@@ -153,23 +141,9 @@ static int rtas_pci_write_config(struct pci_bus *bus, unsigned int devfn, int where, int size, u32 val) { - struct device_node *busdn, *dn; struct pci_dn *pdn; - bool found = false; - - /* Search only direct children of the bus */ - busdn = pci_bus_to_OF_node(bus); - for (dn = busdn->child; dn; dn = dn->sibling) { - pdn = PCI_DN(dn); - if (pdn && pdn->devfn == devfn - && of_device_is_available(dn)) { - found = true; - break; - } - } - if (!found) - return PCIBIOS_DEVICE_NOT_FOUND; + pdn = pci_get_pdn_by_devfn(bus, devfn); return rtas_write_config(pdn, where, size, val); }-- 2.5.4 (Apple Git-61)