The attached patch changes the qemu northbridge.c to read the RAM size
from the i440 PCI bridge configuration registers. This is mostly a
copy-and-paste from the i440bx northbridge.c.
Unfortunately the current version of qemu does not set these
registers, but I have patched qemu so that it emulates the i440 more
faithfully in this regard. The LinuxBIOS patch preserves the existing
behavior--hardcoding the RAM size to 64 MB--when running on an
unpatched qemu.
I have submitted the qemu patch to the qemu-devel list, and will also
include it in my HOWTO.
--Ed
--- LinuxBIOSv2-2401.orig/src/cpu/emulation/qemu-i386/northbridge.c 2005-09-08 17:17:25.000000000 +0000
+++ LinuxBIOSv2-2401/src/cpu/emulation/qemu-i386/northbridge.c 2006-09-13 03:48:36.000000000 +0000
@@ -67,16 +67,40 @@
static void pci_domain_set_resources(device_t dev)
{
+ static const uint8_t ramregs[] = {
+ 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f, 0x56, 0x57
+ };
device_t mc_dev;
uint32_t pci_tolm;
- uint32_t idx;
pci_tolm = find_pci_tolm(&dev->link[0]);
mc_dev = dev->link[0].children;
if (mc_dev) {
unsigned long tomk, tolmk;
- /* Hard code the Top of memory for now */
- tomk = 65536;
+ unsigned char rambits;
+ int i, idx;
+
+ for(rambits = 0, i = 0; i < sizeof(ramregs)/sizeof(ramregs[0]); i++) {
+ unsigned char reg;
+ reg = pci_read_config8(mc_dev, ramregs[i]);
+ /* these are ENDING addresses, not sizes.
+ * if there is memory in this slot, then reg will be > rambits.
+ * So we just take the max, that gives us total.
+ * We take the highest one to cover for once and future linuxbios
+ * bugs. We warn about bugs.
+ */
+ if (reg > rambits)
+ rambits = reg;
+ if (reg < rambits)
+ printk_err("ERROR! register 0x%x is not set!\n",
+ ramregs[i]);
+ }
+ if (rambits == 0) {
+ printk_err("RAM size config registers are empty; defaulting to 64 MBytes\n");
+ rambits = 8;
+ }
+ printk_debug("I would set ram size to 0x%x Kbytes\n", (rambits)*8*1024);
+ tomk = rambits*8*1024;
/* Compute the top of Low memory */
tolmk = pci_tolm >> 10;
if (tolmk >= tomk) {
@@ -84,14 +108,9 @@
*/
tolmk = tomk;
}
-
/* Report the memory regions */
idx = 10;
- ram_resource(dev, idx++, 0, 640);
- ram_resource(dev, idx++, 768, tolmk - 768);
- if (tomk > 4*1024*1024) {
- ram_resource(dev, idx++, 4096*1024, tomk - 4*1024*1024);
- }
+ ram_resource(dev, idx++, 0, tolmk);
}
assign_resources(&dev->link[0]);
}
--
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