-From 03556dab1cb02d85b50d7be3ee3a3bac001f5991 Mon Sep 17 00:00:00 2001
-From: Koen Vandeputte <koen.vandeputte@ncentric.com>
-Date: Tue, 18 Dec 2018 12:14:06 +0100
-Subject: [PATCH] arm: cns3xxx: fix writing to wrong PCI registers after
- alignment
-
-Originally, cns3xxx used it's own functions for mapping, reading and writing registers.
-
-Commit 802b7c06adc7 ("ARM: cns3xxx: Convert PCI to use generic config accessors")
-removed the internal PCI config write function in favor of the generic one:
-
-cns3xxx_pci_write_config() --> pci_generic_config_write()
-
-cns3xxx_pci_write_config() expected aligned addresses, being produced by cns3xxx_pci_map_bus()
-while the generic one pci_generic_config_write() actually expects the real address
-as both the function and hardware are capable of byte-aligned writes.
-
-This currently leads to pci_generic_config_write() writing
-to the wrong registers on some ocasions.
-
-First issue seen due to this:
-
-- driver ath9k gets loaded
-- The driver wants to write value 0xA8 to register PCI_LATENCY_TIMER, located at 0x0D
-- cns3xxx_pci_map_bus() aligns the address to 0x0C
-- pci_generic_config_write() effectively writes 0xA8 into register 0x0C (CACHE_LINE_SIZE)
-
-This seems to cause some slight instability when certain PCI devices are used.
-
-Another issue example caused by this this is the PCI bus numbering,
-where the primary bus is higher than the secondary, which is impossible.
-
-Before:
-
-00:00.0 PCI bridge: Cavium, Inc. Device 3400 (rev 01) (prog-if 00 [Normal decode])
- Flags: bus master, fast devsel, latency 0, IRQ 255
- Bus: primary=02, secondary=01, subordinate=ff, sec-latency=0
-
-After fix:
-
-00:00.0 PCI bridge: Cavium, Inc. Device 3400 (rev 01) (prog-if 00 [Normal decode])
- Flags: bus master, fast devsel, latency 0, IRQ 255
- Bus: primary=00, secondary=01, subordinate=02, sec-latency=0
-
-And very likely some more ..
-
-Fix all by omitting the alignment being done in the mapping function.
-
-Fixes: 802b7c06adc7 ("ARM: cns3xxx: Convert PCI to use generic config accessors")
-Signed-off-by: Koen Vandeputte <koen.vandeputte@ncentric.com>
-CC: Arnd Bergmann <arnd@arndb.de>
-CC: Bjorn Helgaas <bhelgaas@google.com>
-CC: Krzysztof Halasa <khalasa@piap.pl>
-CC: Olof Johansson <olof@lixom.net>
-CC: Robin Leblon <robin.leblon@ncentric.com>
-CC: Rob Herring <robh@kernel.org>
-CC: Russell King <linux@armlinux.org.uk>
-CC: Tim Harvey <tharvey@gateworks.com>
-CC: stable@vger.kernel.org # v4.0+
----
- arch/arm/mach-cns3xxx/pcie.c | 2 +-
- 1 file changed, 1 insertion(+), 1 deletion(-)
-
---- a/arch/arm/mach-cns3xxx/pcie.c
-+++ b/arch/arm/mach-cns3xxx/pcie.c
-@@ -83,7 +83,7 @@ static void __iomem *cns3xxx_pci_map_bus
- } else /* remote PCI bus */
- base = cnspci->cfg1_regs + ((busno & 0xf) << 20);
-
-- return base + (where & 0xffc) + (devfn << 12);
-+ return base + where + (devfn << 12);
- }
-
- static int cns3xxx_pci_read_config(struct pci_bus *bus, unsigned int devfn,
projects / openwrt / staging / wigyori.git / commitdiff