diff options
Diffstat (limited to 'drivers/mtd/maps/amd76xrom.c')
| -rw-r--r-- | drivers/mtd/maps/amd76xrom.c | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/drivers/mtd/maps/amd76xrom.c b/drivers/mtd/maps/amd76xrom.c index 797caffb20b..78b671172bb 100644 --- a/drivers/mtd/maps/amd76xrom.c +++ b/drivers/mtd/maps/amd76xrom.c @@ -7,6 +7,7 @@ #include <linux/module.h> #include <linux/types.h> +#include <linux/version.h> #include <linux/kernel.h> #include <linux/init.h> #include <asm/io.h> @@ -44,6 +45,23 @@ struct amd76xrom_map_info { char map_name[sizeof(MOD_NAME) + 2 + ADDRESS_NAME_LEN]; }; +/* The 2 bits controlling the window size are often set to allow reading + * the BIOS, but too small to allow writing, since the lock registers are + * 4MiB lower in the address space than the data. + * + * This is intended to prevent flashing the bios, perhaps accidentally. + * + * This parameter allows the normal driver to over-ride the BIOS settings. + * + * The bits are 6 and 7. If both bits are set, it is a 5MiB window. + * If only the 7 Bit is set, it is a 4MiB window. Otherwise, a + * 64KiB window. + * + */ +static uint win_size_bits; +module_param(win_size_bits, uint, 0); +MODULE_PARM_DESC(win_size_bits, "ROM window size bits override for 0x43 byte, normally set by BIOS."); + static struct amd76xrom_window amd76xrom_window = { .maps = LIST_HEAD_INIT(amd76xrom_window.maps), }; @@ -95,6 +113,16 @@ static int __devinit amd76xrom_init_one (struct pci_dev *pdev, /* Remember the pci dev I find the window in - already have a ref */ window->pdev = pdev; + /* Enable the selected rom window. This is often incorrectly + * set up by the BIOS, and the 4MiB offset for the lock registers + * requires the full 5MiB of window space. + * + * This 'write, then read' approach leaves the bits for + * other uses of the hardware info. + */ + pci_read_config_byte(pdev, 0x43, &byte); + pci_write_config_byte(pdev, 0x43, byte | win_size_bits ); + /* Assume the rom window is properly setup, and find it's size */ pci_read_config_byte(pdev, 0x43, &byte); if ((byte & ((1<<7)|(1<<6))) == ((1<<7)|(1<<6))) { @@ -129,12 +157,6 @@ static int __devinit amd76xrom_init_one (struct pci_dev *pdev, (unsigned long long)window->rsrc.end); } -#if 0 - - /* Enable the selected rom window */ - pci_read_config_byte(pdev, 0x43, &byte); - pci_write_config_byte(pdev, 0x43, byte | rwindow->segen_bits); -#endif /* Enable writes through the rom window */ pci_read_config_byte(pdev, 0x40, &byte); |