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hw/pci-host/bonito: Allow PCI config accesses smaller than 32-bit

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When running the official PMON firmware for the Fuloong 2E, we see
8-bit and 16-bit accesses to PCI config space:

  $ qemu-system-mips64el -M fuloong2e -bios pmon_2e.bin \
    -trace -trace bonito\* -trace pci_cfg\*

  pci_cfg_write vt82c686b-pm 05:4 @0x90 <- 0xeee1
  bonito_spciconf_small_access PCI config address is smaller then 32-bit, addr: 0x4d2, size: 2
  pci_cfg_write vt82c686b-pm 05:4 @0xd2 <- 0x1
  pci_cfg_write vt82c686b-pm 05:4 @0x4 <- 0x1
  pci_cfg_write vt82c686b-isa 05:0 @0x4 <- 0x7
  bonito_spciconf_small_access PCI config address is smaller then 32-bit, addr: 0x81, size: 1
  pci_cfg_read vt82c686b-isa 05:0 @0x81 -> 0x0
  bonito_spciconf_small_access PCI config address is smaller then 32-bit, addr: 0x81, size: 1
  pci_cfg_write vt82c686b-isa 05:0 @0x81 <- 0x80
  bonito_spciconf_small_access PCI config address is smaller then 32-bit, addr: 0x83, size: 1
  pci_cfg_write vt82c686b-isa 05:0 @0x83 <- 0x89
  bonito_spciconf_small_access PCI config address is smaller then 32-bit, addr: 0x85, size: 1
  pci_cfg_write vt82c686b-isa 05:0 @0x85 <- 0x3
  bonito_spciconf_small_access PCI config address is smaller then 32-bit, addr: 0x5a, size: 1
  pci_cfg_write vt82c686b-isa 05:0 @0x5a <- 0x7
  bonito_spciconf_small_access PCI config address is smaller then 32-bit, addr: 0x85, size: 1
  pci_cfg_write vt82c686b-isa 05:0 @0x85 <- 0x1

Also this is what the Linux kernel does since it supports the Bonito
north bridge:
https://elixir.bootlin.com/linux/v2.6.15/source/arch/mips/pci/ops-bonito64.c#L85

So it seems safe to assume the datasheet is incomplete or outdated
regarding the address constraints.

This problem was exposed by commit 911629e6d3
("vt82c686: Fix SMBus IO base and configuration registers").

Reported-by: BALATON Zoltan <balaton@eik.bme.hu>
Suggested-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Message-Id: <20210624202747.1433023-4-f4bug@amsat.org>
Tested-by: BALATON Zoltan <balaton@eik.bme.hu>
This commit is contained in:
Philippe Mathieu-Daudé 2021-06-24 21:22:19 +02:00
parent 300491f988
commit 711ef33731
1 changed files with 2 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
hw/pci-host/bonito.c
View File

@ -187,7 +187,7 @@ FIELD(BONGENCFG, PCIQUEUE, 12, 1)
#define BONITO_PCICONF_FUN_MASK 0x700 /* [10:8] */
#define BONITO_PCICONF_FUN_OFFSET 8
#define BONITO_PCICONF_REG_MASK_DS (~3) /* Per datasheet */
#define BONITO_PCICONF_REG_MASK 0xFC
#define BONITO_PCICONF_REG_MASK_HW 0xff /* As seen running PMON */
#define BONITO_PCICONF_REG_OFFSET 0
@ -466,7 +466,7 @@ static uint32_t bonito_sbridge_pciaddr(void *opaque, hwaddr addr)
BONITO_PCICONF_IDSEL_OFFSET;
devno = ctz32(idsel);
funno = (cfgaddr & BONITO_PCICONF_FUN_MASK) >> BONITO_PCICONF_FUN_OFFSET;
regno = (cfgaddr & BONITO_PCICONF_REG_MASK) >> BONITO_PCICONF_REG_OFFSET;
regno = (cfgaddr & BONITO_PCICONF_REG_MASK_HW) >> BONITO_PCICONF_REG_OFFSET;
if (idsel == 0) {
error_report("error in bonito pci config address 0x" TARGET_FMT_plx