From: Pali Rohár pali@kernel.org
commit 0c551abfa004ce154d487d91777bf221c808a64f upstream.
By default old pre-3.0 Freescale PCIe controllers reports invalid PCI Class Code 0x0b20 for PCIe Root Port. It can be seen by lspci -b output on P2020 board which has this pre-3.0 controller:
$ lspci -bvnn 00:00.0 Power PC [0b20]: Freescale Semiconductor Inc P2020E [1957:0070] (rev 21) !!! Invalid class 0b20 for header type 01 Capabilities: [4c] Express Root Port (Slot-), MSI 00
Fix this issue by programming correct PCI Class Code 0x0604 for PCIe Root Port to the Freescale specific PCIe register 0x474.
With this change lspci -b output is:
$ lspci -bvnn 00:00.0 PCI bridge [0604]: Freescale Semiconductor Inc P2020E [1957:0070] (rev 21) (prog-if 00 [Normal decode]) Capabilities: [4c] Express Root Port (Slot-), MSI 00
Without any "Invalid class" error. So class code was properly reflected into standard (read-only) PCI register 0x08.
Same fix is already implemented in U-Boot pcie_fsl.c driver in commit: http://source.denx.de/u-boot/u-boot/-/commit/d18d06ac35229345a0af80977a408cf...
Fix activated by U-Boot stay active also after booting Linux kernel. But boards which use older U-Boot version without that fix are affected and still require this fix.
So implement this class code fix also in kernel fsl_pci.c driver.
Cc: stable@vger.kernel.org Signed-off-by: Pali Rohár pali@kernel.org Signed-off-by: Michael Ellerman mpe@ellerman.id.au Link: https://lore.kernel.org/r/20220706101043.4867-1-pali@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- arch/powerpc/sysdev/fsl_pci.c | 8 ++++++++ arch/powerpc/sysdev/fsl_pci.h | 1 + 2 files changed, 9 insertions(+)
--- a/arch/powerpc/sysdev/fsl_pci.c +++ b/arch/powerpc/sysdev/fsl_pci.c @@ -523,6 +523,7 @@ int fsl_add_bridge(struct platform_devic struct resource rsrc; const int *bus_range; u8 hdr_type, progif; + u32 class_code; struct device_node *dev; struct ccsr_pci __iomem *pci; u16 temp; @@ -596,6 +597,13 @@ int fsl_add_bridge(struct platform_devic PPC_INDIRECT_TYPE_SURPRESS_PRIMARY_BUS; if (fsl_pcie_check_link(hose)) hose->indirect_type |= PPC_INDIRECT_TYPE_NO_PCIE_LINK; + /* Fix Class Code to PCI_CLASS_BRIDGE_PCI_NORMAL for pre-3.0 controller */ + if (in_be32(&pci->block_rev1) < PCIE_IP_REV_3_0) { + early_read_config_dword(hose, 0, 0, PCIE_FSL_CSR_CLASSCODE, &class_code); + class_code &= 0xff; + class_code |= PCI_CLASS_BRIDGE_PCI_NORMAL << 8; + early_write_config_dword(hose, 0, 0, PCIE_FSL_CSR_CLASSCODE, class_code); + } } else { /* * Set PBFR(PCI Bus Function Register)[10] = 1 to --- a/arch/powerpc/sysdev/fsl_pci.h +++ b/arch/powerpc/sysdev/fsl_pci.h @@ -23,6 +23,7 @@ struct platform_device;
#define PCIE_LTSSM 0x0404 /* PCIE Link Training and Status */ #define PCIE_LTSSM_L0 0x16 /* L0 state */ +#define PCIE_FSL_CSR_CLASSCODE 0x474 /* FSL GPEX CSR */ #define PCIE_IP_REV_2_2 0x02080202 /* PCIE IP block version Rev2.2 */ #define PCIE_IP_REV_3_0 0x02080300 /* PCIE IP block version Rev3.0 */ #define PIWAR_EN 0x80000000 /* Enable */