X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=src%2Fdos%2Fmtrr.c;fp=src%2Fdos%2Fmtrr.c;h=81badd473d94676ddcaf5c4041a0da919bcc18b5;hb=4e4ac855a9d53fd7dee3d640f3ab46740b991b5c;hp=0000000000000000000000000000000000000000;hpb=f87f51babcc2d9c15e1ecaca19c26acf58292bf7;p=retroray

diff --git a/src/dos/mtrr.c b/src/dos/mtrr.c
new file mode 100644
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);*/
+}