x86: chromebook_link: Implement CAR support (cache as RAM)

Add support for CAR so that we have memory to use prior to DRAM init.
On link there is a total of 128KB of CAR available, although some is
used for the memory reference code.

Signed-off-by: Simon Glass <sjg@chromium.org>

2 files changed, 133 insertions, 1 deletions

diff --git a/arch/x86/include/asm/mtrr.h b/arch/x86/include/asm/mtrr.h
new file mode 100644
index 00000000000..5f05a4848f6
--- /dev/null
+++ b/arch/x86/include/asm/mtrr.h
@@ -0,0 +1,121 @@
+/*
+ * Copyright (c) 2014 Google, Inc
+ *
+ * From Coreboot file of the same name
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef _ASM_MTRR_H
+#define _ASM_MTRR_H
+
+/*  These are the region types  */
+#define MTRR_TYPE_UNCACHEABLE 0
+#define MTRR_TYPE_WRCOMB     1
+/*#define MTRR_TYPE_         2*/
+/*#define MTRR_TYPE_         3*/
+#define MTRR_TYPE_WRTHROUGH  4
+#define MTRR_TYPE_WRPROT     5
+#define MTRR_TYPE_WRBACK     6
+#define MTRR_NUM_TYPES       7
+
+#define MTRRcap_MSR     0x0fe
+#define MTRRdefType_MSR 0x2ff
+
+#define MTRRdefTypeEn		(1 << 11)
+#define MTRRdefTypeFixEn	(1 << 10)
+
+#define SMRRphysBase_MSR 0x1f2
+#define SMRRphysMask_MSR 0x1f3
+
+#define MTRRphysBase_MSR(reg) (0x200 + 2 * (reg))
+#define MTRRphysMask_MSR(reg) (0x200 + 2 * (reg) + 1)
+
+#define MTRRphysMaskValid	(1 << 11)
+
+#define NUM_FIXED_RANGES 88
+#define RANGES_PER_FIXED_MTRR 8
+#define MTRRfix64K_00000_MSR 0x250
+#define MTRRfix16K_80000_MSR 0x258
+#define MTRRfix16K_A0000_MSR 0x259
+#define MTRRfix4K_C0000_MSR 0x268
+#define MTRRfix4K_C8000_MSR 0x269
+#define MTRRfix4K_D0000_MSR 0x26a
+#define MTRRfix4K_D8000_MSR 0x26b
+#define MTRRfix4K_E0000_MSR 0x26c
+#define MTRRfix4K_E8000_MSR 0x26d
+#define MTRRfix4K_F0000_MSR 0x26e
+#define MTRRfix4K_F8000_MSR 0x26f
+
+#if !defined(__ASSEMBLER__)
+
+/*
+ * The MTRR code has some side effects that the callers should be aware for.
+ * 1. The call sequence matters. x86_setup_mtrrs() calls
+ *    x86_setup_fixed_mtrrs_no_enable() then enable_fixed_mtrrs() (equivalent
+ *    of x86_setup_fixed_mtrrs()) then x86_setup_var_mtrrs(). If the callers
+ *    want to call the components of x86_setup_mtrrs() because of other
+ *    rquirements the ordering should still preserved.
+ * 2. enable_fixed_mtrr() will enable both variable and fixed MTRRs because
+ *    of the nature of the global MTRR enable flag. Therefore, all direct
+ *    or indirect callers of enable_fixed_mtrr() should ensure that the
+ *    variable MTRR MSRs do not contain bad ranges.
+ * 3. If CONFIG_CACHE_ROM is selected an MTRR is allocated for enabling
+ *    the caching of the ROM. However, it is set to uncacheable (UC). It
+ *    is the responsiblity of the caller to enable it by calling
+ *    x86_mtrr_enable_rom_caching().
+ */
+void x86_setup_mtrrs(void);
+/*
+ * x86_setup_var_mtrrs() parameters:
+ * address_bits - number of physical address bits supported by cpu
+ * above4gb - 2 means dynamically detect number of variable MTRRs available.
+ *            non-zero means handle memory ranges above 4GiB.
+ *            0 means ignore memory ranges above 4GiB
+ */
+void x86_setup_var_mtrrs(unsigned int address_bits, unsigned int above4gb);
+void enable_fixed_mtrr(void);
+void x86_setup_fixed_mtrrs(void);
+/* Set up fixed MTRRs but do not enable them. */
+void x86_setup_fixed_mtrrs_no_enable(void);
+int x86_mtrr_check(void);
+/* ROM caching can be used after variable MTRRs are set up. Beware that
+ * enabling CONFIG_CACHE_ROM will eat through quite a few MTRRs based on
+ * one's IO hole size and WRCOMB resources. Be sure to check the console
+ * log when enabling CONFIG_CACHE_ROM or adding WRCOMB resources. Beware that
+ * on CPUs with core-scoped MTRR registers such as hyperthreaded CPUs the
+ * rom caching will be disabled if all threads run the MTRR code. Therefore,
+ * one needs to call x86_mtrr_enable_rom_caching() after all threads of the
+ * same core have run the MTRR code. */
+#if CONFIG_CACHE_ROM
+void x86_mtrr_enable_rom_caching(void);
+void x86_mtrr_disable_rom_caching(void);
+/* Return the variable range MTRR index of the ROM cache. */
+long x86_mtrr_rom_cache_var_index(void);
+#else
+static inline void x86_mtrr_enable_rom_caching(void) {}
+static inline void x86_mtrr_disable_rom_caching(void) {}
+static inline long x86_mtrr_rom_cache_var_index(void) { return -1; }
+#endif /* CONFIG_CACHE_ROM */
+
+#endif
+
+#if !defined(CONFIG_RAMTOP)
+# error "CONFIG_RAMTOP not defined"
+#endif
+
+#if ((CONFIG_XIP_ROM_SIZE & (CONFIG_XIP_ROM_SIZE - 1)) != 0)
+# error "CONFIG_XIP_ROM_SIZE is not a power of 2"
+#endif
+
+#if ((CONFIG_CACHE_ROM_SIZE & (CONFIG_CACHE_ROM_SIZE - 1)) != 0)
+# error "CONFIG_CACHE_ROM_SIZE is not a power of 2"
+#endif
+
+#define CACHE_ROM_BASE	(((1 << 20) - (CONFIG_CACHE_ROM_SIZE >> 12)) << 12)
+
+#if (CONFIG_RAMTOP & (CONFIG_RAMTOP - 1)) != 0
+# error "CONFIG_RAMTOP must be a power of 2"
+#endif
+
+#endif
diff --git a/arch/x86/include/asm/post.h b/arch/x86/include/asm/post.h
index 33711854af4..b203dc99b06 100644
--- a/arch/x86/include/asm/post.h
+++ b/arch/x86/include/asm/post.h
@@ -13,9 +13,18 @@
 /* post codes which represent various stages of init */
 #define POST_START		0x1e
 #define POST_CAR_START		0x1f
-
+#define POST_CAR_SIPI		0x20
+#define POST_CAR_MTRR		0x21
+#define POST_CAR_UNCACHEABLE	0x22
+#define POST_CAR_BASE_ADDRESS	0x23
+#define POST_CAR_MASK		0x24
+#define POST_CAR_FILL		0x25
+#define POST_CAR_ROM_CACHE	0x26
+#define POST_CAR_MRC_CACHE	0x27
+#define POST_CAR_CPU_CACHE	0x28
 #define POST_START_STACK	0x29
 #define POST_START_DONE		0x2a
+#define POST_CPU_INIT		0x2b
 
 /* Output a post code using al - value must be 0 to 0xff */
 #ifdef __ASSEMBLY__
@@ -23,6 +32,8 @@
 	movb	$value, %al; \
 	outb	%al, $POST_PORT
 #else
+#include <asm/io.h>
+
 static inline void post_code(int code)
 {
 	outb(code, POST_PORT);