[coreboot] [PATCH] Avoid hang when 4GB or more DRAM is installed on AMD RS780 UMA systems

Scott Duplichan scott at notabs.org
Wed Nov 10 06:13:27 CET 2010


Avoid hang when 4GB or more DRAM is installed on AMD RS780 UMA systems.

-- When building for UMA, reduce the limit for DRAM below 4GB
   from E0000000 to C0000000. This is needed to accomodate the
   UMA frame buffer.
-- Correct problem where msr C0010010 bits 21 and 22 (MtrrTom2En
   and Tom2ForceMemTypeWB) are not set consistently across cores.
-- Enable TOM2 only if DRAM is present above 4GB.
-- Use AMD Tom2ForceMemTypeWB feature to avoid the need for 
   variable MTRR ranges above 4GB.
-- Split function x86_setup_var_mtrrs into standard and AMD versions.
   The AMD version of the function relies on Tom2ForceMemTypeWB for
   making DRAM above 4GB type WB. The AMD version also incorporates
   a change to avoid an unexpected variable MTRR range when using
   UMA graphics.
-- Improve white space consistency for mtrr.c by using tabs in place
   of spaces.
Tested on kino-780am2-fam10 with 2GB and 4GB.
 
Signed-off-by: Scott Duplichan <scott at notabs.org>

Index: src/cpu/amd/mtrr/amd_mtrr.c
===================================================================
--- src/cpu/amd/mtrr/amd_mtrr.c	(revision 6056)
+++ src/cpu/amd/mtrr/amd_mtrr.c	(working copy)
@@ -107,14 +107,14 @@
 	unsigned long address_bits;
 	struct mem_state state;
 	unsigned long i;
-	msr_t msr;
+	msr_t msr, sys_cfg;
 
 
 	/* Enable the access to AMD RdDram and WrDram extension bits */
 	disable_cache();
-	msr = rdmsr(SYSCFG_MSR);
-	msr.lo |= SYSCFG_MSR_MtrrFixDramModEn;
-	wrmsr(SYSCFG_MSR, msr);
+	sys_cfg = rdmsr(SYSCFG_MSR);
+	sys_cfg.lo |= SYSCFG_MSR_MtrrFixDramModEn;
+	wrmsr(SYSCFG_MSR, sys_cfg);
 	enable_cache();
 
 	printk(BIOS_DEBUG, "\n");
@@ -148,11 +148,18 @@
 	msr.lo = state.mmio_basek << 10;
 	wrmsr(TOP_MEM, msr);
 
+	// assume no DRAM above 4GB
+	sys_cfg.lo &= ~SYSCFG_MSR_TOM2En;
+	sys_cfg.lo &= ~SYSCFG_MSR_TOM2WB;
 	if(state.tomk > (4*1024*1024)) {
 		/* Setup TOP_MEM2 */
 		msr.hi = state.tomk >> 22;
 		msr.lo = state.tomk << 10;
 		wrmsr(TOP_MEM2, msr);
+		// enable tom2
+		sys_cfg.lo |= SYSCFG_MSR_TOM2En;
+		// Make DRAM above 4GB WB without using any variable MTRR ranges
+		sys_cfg.lo |= SYSCFG_MSR_TOM2WB;
 	}
 
 	/* zero the IORR's before we enable to prevent
@@ -167,10 +174,9 @@
 	 * Enable the RdMem and WrMem bits in the fixed mtrrs.
 	 * Disable access to the RdMem and WrMem in the fixed mtrr.
 	 */
-	msr = rdmsr(SYSCFG_MSR);
-	msr.lo |= SYSCFG_MSR_MtrrVarDramEn | SYSCFG_MSR_MtrrFixDramEn | SYSCFG_MSR_TOM2En;
-	msr.lo &= ~SYSCFG_MSR_MtrrFixDramModEn;
-	wrmsr(SYSCFG_MSR, msr);
+	sys_cfg.lo |= SYSCFG_MSR_MtrrVarDramEn | SYSCFG_MSR_MtrrFixDramEn;
+	sys_cfg.lo &= ~SYSCFG_MSR_MtrrFixDramModEn;
+	wrmsr(SYSCFG_MSR, sys_cfg);
 
 	enable_fixed_mtrr();
 
@@ -186,5 +192,5 @@
 	/* Now that I have mapped what is memory and what is not
 	 * Setup the mtrrs so we can cache the memory.
 	 */
-	x86_setup_var_mtrrs(address_bits);
+	amd_setup_var_mtrrs(address_bits);
 }
Index: src/cpu/x86/mtrr/mtrr.c
===================================================================
--- src/cpu/x86/mtrr/mtrr.c	(revision 6056)
+++ src/cpu/x86/mtrr/mtrr.c	(working copy)
@@ -364,31 +364,30 @@
 
 void x86_setup_fixed_mtrrs(void)
 {
-        /* Try this the simple way of incrementally adding together
-         * mtrrs.  If this doesn't work out we can get smart again
-         * and clear out the mtrrs.
-         */
+	/* Try this the simple way of incrementally adding together
+	 * mtrrs.  If this doesn't work out we can get smart again
+	 * and clear out the mtrrs.
+	 */
 
-        printk(BIOS_DEBUG, "\n");
-        /* Initialized the fixed_mtrrs to uncached */
-        printk(BIOS_DEBUG, "Setting fixed MTRRs(%d-%d) Type: UC\n",
-	        0, NUM_FIXED_RANGES);
-        set_fixed_mtrrs(0, NUM_FIXED_RANGES, MTRR_TYPE_UNCACHEABLE);
+	printk(BIOS_DEBUG, "\n");
+	/* Initialized the fixed_mtrrs to uncached */
+	printk(BIOS_DEBUG, "Setting fixed MTRRs(%d-%d) Type: UC\n",
+		0, NUM_FIXED_RANGES);
+	set_fixed_mtrrs(0, NUM_FIXED_RANGES, MTRR_TYPE_UNCACHEABLE);
 
-        /* Now see which of the fixed mtrrs cover ram.
-                 */
-        search_global_resources(
+	/* Now see which of the fixed mtrrs cover ram. */
+	search_global_resources(
 		IORESOURCE_MEM | IORESOURCE_CACHEABLE, IORESOURCE_MEM | IORESOURCE_CACHEABLE,
 		set_fixed_mtrr_resource, NULL);
-        printk(BIOS_DEBUG, "DONE fixed MTRRs\n");
+	printk(BIOS_DEBUG, "DONE fixed MTRRs\n");
 
-        /* enable fixed MTRR */
-        printk(BIOS_SPEW, "call enable_fixed_mtrr()\n");
-        enable_fixed_mtrr();
+	/* enable fixed MTRR */
+	printk(BIOS_SPEW, "call enable_fixed_mtrr()\n");
+	enable_fixed_mtrr();
 
 }
 
-void x86_setup_var_mtrrs(unsigned address_bits)
+static void x86_setup_var_mtrrs(unsigned address_bits)
 /* this routine needs to know how many address bits a given processor
  * supports.  CPUs get grumpy when you set too many bits in
  * their mtrr registers :(  I would generically call cpuid here
@@ -449,6 +448,64 @@
 	post_code(0x6A);
 }
 
+
+void amd_setup_var_mtrrs(unsigned address_bits)
+/* this routine needs to know how many address bits a given processor
+ * supports.  CPUs get grumpy when you set too many bits in
+ * their mtrr registers :(  I would generically call cpuid here
+ * and find out how many physically supported but some cpus are
+ * buggy, and report more bits then they actually support.
+ */
+{
+	/* Try this the simple way of incrementally adding together
+	 * mtrrs.  If this doesn't work out we can get smart again
+	 * and clear out the mtrrs.
+	 */
+	struct var_mtrr_state var_state;
+
+	/* Cache as many memory areas as possible */
+	/* FIXME is there an algorithm for computing the optimal set of mtrrs?
+	 * In some cases it is definitely possible to do better.
+	 */
+
+	var_state.range_startk = 0;
+	var_state.range_sizek = 0;
+	var_state.hole_startk = 0;
+	var_state.hole_sizek = 0;
+	var_state.reg = 0;
+	var_state.address_bits = address_bits;
+
+	search_global_resources(
+		IORESOURCE_MEM | IORESOURCE_CACHEABLE, IORESOURCE_MEM | IORESOURCE_CACHEABLE,
+		set_var_mtrr_resource, &var_state);
+
+	if (var_state.range_sizek >= 0x100000000ull / 1024 && var_state.range_startk == 0)
+		{
+		// no variable MTRR range is needed for WB from 4GB-TOM2
+		// because Tom2ForceMemTypeWB will be used for this purpose.
+		var_state.range_sizek = var_state.hole_startk;
+		}
+
+#if (CONFIG_GFXUMA == 1) /* UMA or SP. */
+	// For now we assume the UMA space is at the end of memory below 4GB
+	// Reduce the dram wb mtrr range so that it does not cover the uma at the end
+	var_state.range_sizek -= (uma_memory_size >> 10);
+#endif
+	/* Write the last range */
+	var_state.reg = range_to_mtrr(var_state.reg, var_state.range_startk,
+		var_state.range_sizek, 0, MTRR_TYPE_WRBACK, var_state.address_bits);
+	printk(BIOS_DEBUG, "DONE variable MTRRs\n");
+	printk(BIOS_DEBUG, "Clear out the extra MTRR's\n");
+	/* Clear out the extra MTRR's */
+	while(var_state.reg < MTRRS) {
+		set_var_mtrr(var_state.reg++, 0, 0, 0, var_state.address_bits);
+	}
+	printk(BIOS_SPEW, "call enable_var_mtrr()\n");
+	enable_var_mtrr();
+	printk(BIOS_SPEW, "Leave %s\n", __func__);
+	post_code(0x6A);
+}
+
 void x86_setup_mtrrs(unsigned address_bits)
 {
 	x86_setup_fixed_mtrrs();
Index: src/include/cpu/amd/mtrr.h
===================================================================
--- src/include/cpu/amd/mtrr.h	(revision 6056)
+++ src/include/cpu/amd/mtrr.h	(working copy)
@@ -8,6 +8,7 @@
 #define MTRR_WRITE_MEM			(1 << 3)
 
 #define SYSCFG_MSR			0xC0010010
+#define SYSCFG_MSR_TOM2WB		(1 << 22)
 #define SYSCFG_MSR_TOM2En		(1 << 21)
 #define SYSCFG_MSR_MtrrVarDramEn	(1 << 20)
 #define SYSCFG_MSR_MtrrFixDramModEn	(1 << 19)
Index: src/include/cpu/x86/mtrr.h
===================================================================
--- src/include/cpu/x86/mtrr.h	(revision 6056)
+++ src/include/cpu/x86/mtrr.h	(working copy)
@@ -37,7 +37,7 @@
 #if !defined (ASSEMBLY) && !defined(__PRE_RAM__)
 #include <device/device.h>
 void enable_fixed_mtrr(void);
-void x86_setup_var_mtrrs(unsigned address_bits);
+void amd_setup_var_mtrrs(unsigned address_bits);
 void x86_setup_mtrrs(unsigned address_bits);
 int x86_mtrr_check(void);
 void set_var_mtrr_resource(void *gp, struct device *dev, struct resource *res);
Index: src/northbridge/amd/amdmct/wrappers/mcti.h
===================================================================
--- src/northbridge/amd/amdmct/wrappers/mcti.h	(revision 6056)
+++ src/northbridge/amd/amdmct/wrappers/mcti.h	(working copy)
@@ -42,11 +42,12 @@
 //#define    SYSTEM_TYPE     MOBILE
 #endif
 
-/*----------------------------------------------------------------------------
-COMMENT OUT ALL BUT 1
-----------------------------------------------------------------------------*/
+/*--------------------------------------------------------------------------*/
+#if (CONFIG_GFXUMA)
+#define UMA_SUPPORT	1	/*Supported */
+#else
 #define UMA_SUPPORT	0	/*Not supported */
-//#define UMA_SUPPORT	1	/*Supported */
+#endif
 
 /*----------------------------------------------------------------------------
 UPDATE AS NEEDED
Index: src/northbridge/amd/amdmct/wrappers/mcti_d.c
===================================================================
--- src/northbridge/amd/amdmct/wrappers/mcti_d.c	(revision 6056)
+++ src/northbridge/amd/amdmct/wrappers/mcti_d.c	(working copy)
@@ -132,13 +132,17 @@
 		//val = 1;	/* enable */
 		break;
 	case NV_BottomIO:
+#if (UMA_SUPPORT == 0)
 		val = 0xE0;	/* address bits [31:24] */
+#elif (UMA_SUPPORT == 1)
+		val = 0xC0;	/* address bits [31:24] */
+#endif
 		break;
 	case NV_BottomUMA:
 #if (UMA_SUPPORT == 0)
 		val = 0xE0;	/* address bits [31:24] */
 #elif (UMA_SUPPORT == 1)
-		val = 0xB0;	/* address bits [31:24] */
+		val = 0xC0;	/* address bits [31:24] */
 #endif
 		break;
 	case NV_ECC:
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