switched to vidsys (not working yet)

[retroray] / src / dos / mtrr.c

diff --git a/src/dos/mtrr.c b/src/dos/mtrr.c
new file mode 100644 (file)
index 0000000..81badd4
--- /dev/null
+++ b/src/dos/mtrr.c
@@ -0,0 +1,149 @@
+#include "mtrr.h"
+
+#define MSR_MTRRCAP                    0xfe
+#define MSR_MTRRDEFTYPE                0x2ff
+#define MSR_MTRRBASE(x)                (0x200 | ((x) << 1))
+#define MSR_MTRRMASK(x)                (0x201 | ((x) << 1))
+#define MTRRDEF_EN                     0x800
+#define MTRRCAP_HAVE_WC                0x400
+#define MTRRMASK_VALID         0x800
+
+static const char *mtrr_type_name(int type);
+static void print_mtrr(void);
+
+
+int get_page_memtype(uint32_t addr, int num_ranges)
+{
+       int i;
+       uint32_t rlow, rhigh;
+       uint32_t base, mask;
+
+       for(i=0; i<num_ranges; i++) {
+               get_msr(MSR_MTRRMASK(i), &rlow, &rhigh);
+               if(!(rlow & MTRRMASK_VALID)) {
+                       continue;
+               }
+               mask = rlow & 0xfffff000;
+
+               get_msr(MSR_MTRRBASE(i), &rlow, &rhigh);
+               base = rlow & 0xfffff000;
+
+               if((addr & mask) == (base & mask)) {
+                       return rlow & 0xff;
+               }
+       }
+
+       get_msr(MSR_MTRRDEFTYPE, &rlow, &rhigh);
+       return rlow & 0xff;
+}
+
+int check_wrcomb_enabled(uint32_t addr, int len, int num_ranges)
+{
+       while(len > 0) {
+               if(get_page_memtype(addr, num_ranges) != MTRR_WC) {
+                       return 0;
+               }
+               addr += 4096;
+               len -= 4096;
+       }
+       return 1;
+}
+
+int alloc_mtrr(int num_ranges)
+{
+       int i;
+       uint32_t rlow, rhigh;
+
+       for(i=0; i<num_ranges; i++) {
+               get_msr(MSR_MTRRMASK(i), &rlow, &rhigh);
+               if(!(rlow & MTRRMASK_VALID)) {
+                       return i;
+               }
+       }
+       return -1;
+}
+
+void enable_wrcomb(uint32_t addr, int len)
+{
+       int num_ranges, mtrr;
+       uint32_t rlow, rhigh;
+       uint32_t def, mask;
+
+       if(len <= 0 || (addr | (uint32_t)len) & 0xfff) {
+               errormsg("failed to enable write combining, unaligned range: %p/%x\n",
+                               (void*)addr, (unsigned int)len);
+               return;
+       }
+
+       get_msr(MSR_MTRRCAP, &rlow, &rhigh);
+       num_ranges = rlow & 0xff;
+
+       infomsg("enable_wrcomb: addr=%p len=%x\n", (void*)addr, (unsigned int)len);
+
+       if(!(rlow & MTRRCAP_HAVE_WC)) {
+               errormsg("failed to enable write combining, processor doesn't support it\n");
+               return;
+       }
+
+       if(check_wrcomb_enabled(addr, len, num_ranges)) {
+               return;
+       }
+
+       if((mtrr = alloc_mtrr(num_ranges)) == -1) {
+               errormsg("failed to enable write combining, no free MTRRs\n");
+               return;
+       }
+
+       mask = len - 1;
+       mask |= mask >> 1;
+       mask |= mask >> 2;
+       mask |= mask >> 4;
+       mask |= mask >> 8;
+       mask |= mask >> 16;
+       mask = ~mask & 0xfffff000;
+
+       infomsg("  ... mask: %08x\n", (unsigned int)mask);
+
+       _disable();
+       get_msr(MSR_MTRRDEFTYPE, &def, &rhigh);
+       set_msr(MSR_MTRRDEFTYPE, def & ~MTRRDEF_EN, rhigh);
+
+       set_msr(MSR_MTRRBASE(mtrr), addr | MTRR_WC, 0);
+       set_msr(MSR_MTRRMASK(mtrr), mask | MTRRMASK_VALID, 0);
+
+       set_msr(MSR_MTRRDEFTYPE, def | MTRRDEF_EN, 0);
+       _enable();
+}
+
+static const char *mtrr_names[] = { "N/A", "W C", "N/A", "N/A", "W T", "W P", "W B" };
+
+static const char *mtrr_type_name(int type)
+{
+       if(type < 0 || type >= sizeof mtrr_names / sizeof *mtrr_names) {
+               return mtrr_names[0];
+       }
+       return mtrr_names[type];
+}
+
+static void print_mtrr(void)
+{
+       int i, num_ranges;
+       uint32_t rlow, rhigh, base, mask;
+
+       get_msr(MSR_MTRRCAP, &rlow, &rhigh);
+       num_ranges = rlow & 0xff;
+
+       for(i=0; i<num_ranges; i++) {
+               get_msr(MSR_MTRRBASE(i), &base, &rhigh);
+               get_msr(MSR_MTRRMASK(i), &mask, &rhigh);
+
+               if(mask & MTRRMASK_VALID) {
+                       infomsg("mtrr%d: base %p, mask %08x type %s\n", i, (void*)(base & 0xfffff000),
+                                       (unsigned int)(mask & 0xfffff000), mtrr_type_name(base & 0xff));
+               } else {
+                       infomsg("mtrr%d unused (%08x/%08x)\n", i, (unsigned int)base,
+                                       (unsigned int)mask);
+               }
+       }
+       /*fflush(stdout);*/
+}