summaryrefslogtreecommitdiffstats
path: root/arch/x86/kernel/cpu/mtrr/amd.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/x86/kernel/cpu/mtrr/amd.c')
-rw-r--r--arch/x86/kernel/cpu/mtrr/amd.c97
1 files changed, 51 insertions, 46 deletions
diff --git a/arch/x86/kernel/cpu/mtrr/amd.c b/arch/x86/kernel/cpu/mtrr/amd.c
index ee2331b0e58..33af14110df 100644
--- a/arch/x86/kernel/cpu/mtrr/amd.c
+++ b/arch/x86/kernel/cpu/mtrr/amd.c
@@ -7,15 +7,15 @@
static void
amd_get_mtrr(unsigned int reg, unsigned long *base,
- unsigned long *size, mtrr_type * type)
+ unsigned long *size, mtrr_type *type)
{
unsigned long low, high;
rdmsr(MSR_K6_UWCCR, low, high);
- /* Upper dword is region 1, lower is region 0 */
+ /* Upper dword is region 1, lower is region 0 */
if (reg == 1)
low = high;
- /* The base masks off on the right alignment */
+ /* The base masks off on the right alignment */
*base = (low & 0xFFFE0000) >> PAGE_SHIFT;
*type = 0;
if (low & 1)
@@ -27,74 +27,81 @@ amd_get_mtrr(unsigned int reg, unsigned long *base,
return;
}
/*
- * This needs a little explaining. The size is stored as an
- * inverted mask of bits of 128K granularity 15 bits long offset
- * 2 bits
+ * This needs a little explaining. The size is stored as an
+ * inverted mask of bits of 128K granularity 15 bits long offset
+ * 2 bits.
*
- * So to get a size we do invert the mask and add 1 to the lowest
- * mask bit (4 as its 2 bits in). This gives us a size we then shift
- * to turn into 128K blocks
+ * So to get a size we do invert the mask and add 1 to the lowest
+ * mask bit (4 as its 2 bits in). This gives us a size we then shift
+ * to turn into 128K blocks.
*
- * eg 111 1111 1111 1100 is 512K
+ * eg 111 1111 1111 1100 is 512K
*
- * invert 000 0000 0000 0011
- * +1 000 0000 0000 0100
- * *128K ...
+ * invert 000 0000 0000 0011
+ * +1 000 0000 0000 0100
+ * *128K ...
*/
low = (~low) & 0x1FFFC;
*size = (low + 4) << (15 - PAGE_SHIFT);
- return;
}
-static void amd_set_mtrr(unsigned int reg, unsigned long base,
- unsigned long size, mtrr_type type)
-/* [SUMMARY] Set variable MTRR register on the local CPU.
- <reg> The register to set.
- <base> The base address of the region.
- <size> The size of the region. If this is 0 the region is disabled.
- <type> The type of the region.
- [RETURNS] Nothing.
-*/
+/**
+ * amd_set_mtrr - Set variable MTRR register on the local CPU.
+ *
+ * @reg The register to set.
+ * @base The base address of the region.
+ * @size The size of the region. If this is 0 the region is disabled.
+ * @type The type of the region.
+ *
+ * Returns nothing.
+ */
+static void
+amd_set_mtrr(unsigned int reg, unsigned long base, unsigned long size, mtrr_type type)
{
u32 regs[2];
/*
- * Low is MTRR0 , High MTRR 1
+ * Low is MTRR0, High MTRR 1
*/
rdmsr(MSR_K6_UWCCR, regs[0], regs[1]);
/*
- * Blank to disable
+ * Blank to disable
*/
- if (size == 0)
+ if (size == 0) {
regs[reg] = 0;
- else
- /* Set the register to the base, the type (off by one) and an
- inverted bitmask of the size The size is the only odd
- bit. We are fed say 512K We invert this and we get 111 1111
- 1111 1011 but if you subtract one and invert you get the
- desired 111 1111 1111 1100 mask
-
- But ~(x - 1) == ~x + 1 == -x. Two's complement rocks! */
+ } else {
+ /*
+ * Set the register to the base, the type (off by one) and an
+ * inverted bitmask of the size The size is the only odd
+ * bit. We are fed say 512K We invert this and we get 111 1111
+ * 1111 1011 but if you subtract one and invert you get the
+ * desired 111 1111 1111 1100 mask
+ *
+ * But ~(x - 1) == ~x + 1 == -x. Two's complement rocks!
+ */
regs[reg] = (-size >> (15 - PAGE_SHIFT) & 0x0001FFFC)
| (base << PAGE_SHIFT) | (type + 1);
+ }
/*
- * The writeback rule is quite specific. See the manual. Its
- * disable local interrupts, write back the cache, set the mtrr
+ * The writeback rule is quite specific. See the manual. Its
+ * disable local interrupts, write back the cache, set the mtrr
*/
wbinvd();
wrmsr(MSR_K6_UWCCR, regs[0], regs[1]);
}
-static int amd_validate_add_page(unsigned long base, unsigned long size, unsigned int type)
+static int
+amd_validate_add_page(unsigned long base, unsigned long size, unsigned int type)
{
- /* Apply the K6 block alignment and size rules
- In order
- o Uncached or gathering only
- o 128K or bigger block
- o Power of 2 block
- o base suitably aligned to the power
- */
+ /*
+ * Apply the K6 block alignment and size rules
+ * In order
+ * o Uncached or gathering only
+ * o 128K or bigger block
+ * o Power of 2 block
+ * o base suitably aligned to the power
+ */
if (type > MTRR_TYPE_WRCOMB || size < (1 << (17 - PAGE_SHIFT))
|| (size & ~(size - 1)) - size || (base & (size - 1)))
return -EINVAL;
@@ -115,5 +122,3 @@ int __init amd_init_mtrr(void)
set_mtrr_ops(&amd_mtrr_ops);
return 0;
}
-
-//arch_initcall(amd_mtrr_init);