* Handle the memory map.
* The functions here do the job until bootmem takes over.
* $Id: e820.c,v 1.4 2002/09/19 19:25:32 ak Exp $
+ *
+ * Getting sanitize_e820_map() in sync with i386 version by applying change:
+ * - Provisions for empty E820 memory regions (reported by certain BIOSes).
+ * Alex Achenbach <xela@slit.de>, December 2002.
+ * Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
+ *
*/
#include <linux/config.h>
#include <linux/kernel.h>
int chgidx, still_changing;
int overlap_entries;
int new_bios_entry;
- int old_nr, new_nr;
+ int old_nr, new_nr, chg_nr;
int i;
/*
for (i=0; i < 2*old_nr; i++)
change_point[i] = &change_point_list[i];
- /* record all known change-points (starting and ending addresses) */
+ /* record all known change-points (starting and ending addresses),
+ omitting those that are for empty memory regions */
chgidx = 0;
for (i=0; i < old_nr; i++) {
- change_point[chgidx]->addr = biosmap[i].addr;
- change_point[chgidx++]->pbios = &biosmap[i];
- change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size;
- change_point[chgidx++]->pbios = &biosmap[i];
+ if (biosmap[i].size != 0) {
+ change_point[chgidx]->addr = biosmap[i].addr;
+ change_point[chgidx++]->pbios = &biosmap[i];
+ change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size;
+ change_point[chgidx++]->pbios = &biosmap[i];
+ }
}
+ chg_nr = chgidx;
/* sort change-point list by memory addresses (low -> high) */
still_changing = 1;
while (still_changing) {
still_changing = 0;
- for (i=1; i < 2*old_nr; i++) {
+ for (i=1; i < chg_nr; i++) {
/* if <current_addr> > <last_addr>, swap */
/* or, if current=<start_addr> & last=<end_addr>, swap */
if ((change_point[i]->addr < change_point[i-1]->addr) ||
last_type = 0; /* start with undefined memory type */
last_addr = 0; /* start with 0 as last starting address */
/* loop through change-points, determining affect on the new bios map */
- for (chgidx=0; chgidx < 2*old_nr; chgidx++)
+ for (chgidx=0; chgidx < chg_nr; chgidx++)
{
/* keep track of all overlapping bios entries */
if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr)
void __init parse_memopt(char *p, char **from)
{
- /*
- * mem=XXX[kKmM] limits kernel memory to XXX+1MB
- *
- * It would be more logical to count from 0 instead of from
- * HIGH_MEMORY, but we keep that for now for i386 compatibility.
- *
- * No support for custom mapping like i386. The reason is
- * that we need to read the e820 map anyways to handle the
- * ACPI mappings in the direct map. Also on x86-64 there
- * should be always a good e820 map. This is only an upper
- * limit, you cannot force usage of memory not in e820.
- *
- * -AK
- */
- end_user_pfn = memparse(p, from) + HIGH_MEMORY;
+ end_user_pfn = memparse(p, from);
end_user_pfn >>= PAGE_SHIFT;
}
+unsigned long pci_mem_start = 0xaeedbabe;
+
+/*
+ * Search for the biggest gap in the low 32 bits of the e820
+ * memory space. We pass this space to PCI to assign MMIO resources
+ * for hotplug or unconfigured devices in.
+ * Hopefully the BIOS let enough space left.
+ */
+__init void e820_setup_gap(void)
+{
+ unsigned long gapstart, gapsize;
+ unsigned long last;
+ int i;
+ int found = 0;
+
+ last = 0x100000000ull;
+ gapstart = 0x10000000;
+ gapsize = 0x400000;
+ i = e820.nr_map;
+ while (--i >= 0) {
+ unsigned long long start = e820.map[i].addr;
+ unsigned long long end = start + e820.map[i].size;
+
+ /*
+ * Since "last" is at most 4GB, we know we'll
+ * fit in 32 bits if this condition is true
+ */
+ if (last > end) {
+ unsigned long gap = last - end;
+
+ if (gap > gapsize) {
+ gapsize = gap;
+ gapstart = end;
+ found = 1;
+ }
+ }
+ if (start < last)
+ last = start;
+ }
+
+ if (!found) {
+ gapstart = (end_pfn << PAGE_SHIFT) + 1024*1024;
+ printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit address range\n"
+ KERN_ERR "PCI: Unassigned devices with 32bit resource registers may break!\n");
+ }
+
+ /*
+ * Start allocating dynamic PCI memory a bit into the gap,
+ * aligned up to the nearest megabyte.
+ *
+ * Question: should we try to pad it up a bit (do something
+ * like " + (gapsize >> 3)" in there too?). We now have the
+ * technology.
+ */
+ pci_mem_start = (gapstart + 0xfffff) & ~0xfffff;
+
+ printk(KERN_INFO "Allocating PCI resources starting at %lx (gap: %lx:%lx)\n",
+ pci_mem_start, gapstart, gapsize);
+}
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