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x86: qemu: Turn on legacy segments decode 

By default the legacy segments C/D/E/F do not decode to system RAM.
Turn on the decode via Programmable Attribute Map (PAM) registers
so that we can write configuration tables in the F segment.

Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
This commit is contained in:
Bin Meng 2015-05-24 00:12:33 +08:00 committed by Simon Glass
parent 5466983200
commit cc7debc719
2 changed files with 26 additions and 0 deletions
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20
arch/x86/cpu/qemu/pci.c
View File

@ -7,6 +7,8 @@
#include <common.h>
#include <pci.h>
#include <pci_rom.h>
#include <asm/pci.h>
#include <asm/arch/qemu.h>
DECLARE_GLOBAL_DATA_PTR;
@ -50,6 +52,8 @@ int board_pci_post_scan(struct pci_controller *hose)
ulong start;
pci_dev_t bdf;
struct pci_device_id graphic_card[] = { { 0x1234, 0x1111 } };
u16 device;
int pam, i;
/*
* QEMU emulated graphic card shows in the PCI configuration space with
@ -67,5 +71,21 @@ int board_pci_post_scan(struct pci_controller *hose)
debug("BIOS ran in %lums\n", get_timer(start));
}
/*
* i440FX and Q35 chipset have different PAM register offset, but with
* the same bitfield layout. Here we determine the offset based on its
* PCI device ID.
*/
device = x86_pci_read_config16(PCI_BDF(0, 0, 0), PCI_DEVICE_ID);
pam = (device == PCI_DEVICE_ID_INTEL_82441) ? I440FX_PAM : Q35_PAM;
/*
* Initialize Programmable Attribute Map (PAM) Registers
*
* Configure legacy segments C/D/E/F to system RAM
*/
for (i = 0; i < PAM_NUM; i++)
x86_pci_write_config8(PCI_BDF(0, 0, 0), pam + i, PAM_RW);
return ret;
}

6
arch/x86/include/asm/arch-qemu/qemu.h
View File

@ -7,6 +7,12 @@
#ifndef _ARCH_QEMU_H_
#define _ARCH_QEMU_H_
/* Programmable Attribute Map (PAM) Registers */
#define I440FX_PAM 0x59
#define Q35_PAM 0x90
#define PAM_NUM 7
#define PAM_RW 0x33
/* I/O Ports */
#define CMOS_ADDR_PORT 0x70
#define CMOS_DATA_PORT 0x71