soc/intel: Rename IA common code module from `TOM` to `RAMTOP`

This patch renames all references of `top_of_ram` (TOM) in IA common
`basecode` module (for example: functions, variables, Kconfig,
Makefile and comments) with `ramtop` aka top_of_ram to make it more
meaningful and to avoid conflicts with Intel SA chipset TOM registers.

BUG=Able to build and boot google/rex with the same ~49ms savings
in place.

Change-Id: Icfe6300a8e4c5761064537fb256cfecbe2afb2d8
Signed-off-by: Subrata Banik <subratabanik@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/73881
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/drivers/intel/fsp2_0/memory_init.c

@@ -24,8 +24,8 @@
 #include <types.h>
 #include <vb2_api.h>
 
-#if CONFIG(SOC_INTEL_COMMON_BASECODE_TOM)
+#if CONFIG(SOC_INTEL_COMMON_BASECODE_RAMTOP)
-#include <intelbasecode/tom.h>
+#include <intelbasecode/ramtop.h>
 #endif
 
 static uint8_t temp_ram[CONFIG_FSP_TEMP_RAM_SIZE] __aligned(sizeof(uint64_t));
@@ -259,10 +259,10 @@ static void do_fsp_memory_init(const struct fspm_context *context, bool s3wake)
 		die_with_post_code(POST_INVALID_VENDOR_BINARY,
 			"FSPM_ARCH_UPD not found!\n");
 
-	/* Early caching of TOM region if valid mrc cache data is found */
+	/* Early caching of RAMTOP region if valid mrc cache data is found */
-#if (CONFIG(SOC_INTEL_COMMON_BASECODE_TOM))
+#if (CONFIG(SOC_INTEL_COMMON_BASECODE_RAMTOP))
 	if (arch_upd->NvsBufferPtr)
-		early_tom_enable_cache_range();
+		early_ramtop_enable_cache_range();
 #endif
 
 	/* Give SoC and mainboard a chance to update the UPD */

src/soc/intel/common/basecode/include/intelbasecode/ramtop.h

@@ -0,0 +1,14 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#ifndef SOC_INTEL_COMMON_BASECODE_RAMTOP_H
+#define SOC_INTEL_COMMON_BASECODE_RAMTOP_H
+
+#include <types.h>
+
+/* Early caching of top_of_ram region */
+void early_ramtop_enable_cache_range(void);
+
+/* Update the RAMTOP if required based on the input top_of_ram address */
+void update_ramtop(uint32_t addr);
+
+#endif

src/soc/intel/common/basecode/include/intelbasecode/tom.h

@@ -1,14 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-
-#ifndef SOC_INTEL_COMMON_BASECODE_TOM_H
-#define SOC_INTEL_COMMON_BASECODE_TOM_H
-
-#include <types.h>
-
-/* Early caching of TOM region */
-void early_tom_enable_cache_range(void);
-
-/* Update the TOM if required based on the input TOM address */
-void update_tom(uint32_t addr);
-
-#endif

src/soc/intel/common/basecode/ramtop/Kconfig

@@ -1,15 +1,15 @@
-config SOC_INTEL_COMMON_BASECODE_TOM
+config SOC_INTEL_COMMON_BASECODE_RAMTOP
 	bool
 	default n
 	help
-	  Driver code to store the top_of_ram (TOM) address into
+	  Driver code to store the top_of_ram (RAMTOP) address into
 	  non-volatile space (CMOS) during the first boot and use
 	  it across all consecutive boot.
 
-	  Purpose of this driver code is to cache the TOM (with a
+	  Purpose of this driver code is to cache the RAMTOP (with a
 	  fixed size) for all consecutive boots even before calling
 	  into the FSP. Otherwise, this range remains un-cached until postcar
 	  boot stage updates the MTRR programming. FSP-M and late romstage
-	  uses this uncached TOM range for various purposes and having the
+	  uses this uncached RAMTOP range for various purposes and having the
 	  ability to cache this range beforehand would help to optimize the boot
 	  time (more than 50ms).

src/soc/intel/common/basecode/ramtop/Makefile.inc

@@ -0,0 +1,2 @@
+## SPDX-License-Identifier: GPL-2.0-only
+romstage-$(CONFIG_SOC_INTEL_COMMON_BASECODE_RAMTOP) += ramtop.c

src/soc/intel/common/basecode/ramtop/ramtop.c

@@ -0,0 +1,127 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <console/console.h>
+#include <cpu/x86/mtrr.h>
+#include <ip_checksum.h>
+#include <intelbasecode/ramtop.h>
+#include <pc80/mc146818rtc.h>
+#include <stdint.h>
+
+/* We need a region in CMOS to store the RAMTOP address */
+
+#define RAMTOP_SIGNATURE   0x52544F50 /* 'RTOP' */
+
+#define RAMTOP_CMOS_OFFSET 0x64
+
+/*
+ * Address of the ramtop_cmos_offset byte in CMOS. Should be reserved
+ * in mainboards' cmos.layout and not covered by checksum.
+ */
+
+#if CONFIG(USE_OPTION_TABLE)
+#include "option_table.h"
+#if CMOS_VSTART_ramtop_cmos_offset != RAMTOP_CMOS_OFFSET * 8
+#error "CMOS start for RAMTOP_CMOS is not correct, check your cmos.layout"
+#endif
+#if CMOS_VLEN_ramtop_cmos_offset != 12
+#error "CMOS length for RAMTOP_CMOS bytes are not correct, check your cmos.layout"
+#endif
+#endif
+
+struct ramtop_table {
+	uint32_t signature;
+	uint32_t addr;
+	uint16_t checksum;
+} __packed;
+
+/* Read and validate ramtop_table structure from CMOS */
+static int ramtop_cmos_read(struct ramtop_table *ramtop)
+{
+	u8 i, *p;
+	u16 csum;
+
+	for (p = (u8 *)ramtop, i = 0; i < sizeof(*ramtop); i++, p++)
+		*p = cmos_read(RAMTOP_CMOS_OFFSET + i);
+
+	/* Verify signature */
+	if (ramtop->signature != RAMTOP_SIGNATURE) {
+		printk(BIOS_DEBUG, "ramtop_table invalid signature\n");
+		return -1;
+	}
+
+	/* Verify checksum over signature and counter only */
+	csum = compute_ip_checksum(ramtop, offsetof(struct ramtop_table, checksum));
+
+	if (csum != ramtop->checksum) {
+		printk(BIOS_DEBUG, "ramtop_table checksum mismatch\n");
+		return -1;
+	}
+
+	return 0;
+}
+
+/* Write ramtop_table structure to CMOS */
+static void ramtop_cmos_write(struct ramtop_table *ramtop)
+{
+	u8 i, *p;
+
+	/* Checksum over signature and counter only */
+	ramtop->checksum = compute_ip_checksum(
+		ramtop, offsetof(struct ramtop_table, checksum));
+
+	for (p = (u8 *)ramtop, i = 0; i < sizeof(*ramtop); i++, p++)
+		cmos_write(*p, RAMTOP_CMOS_OFFSET + i);
+}
+
+/* Update the RAMTOP if required based on the input top_of_ram address */
+void update_ramtop(uint32_t addr)
+{
+	struct ramtop_table ramtop;
+
+	/* Read and update ramtop (if required) */
+	if (ramtop_cmos_read(&ramtop) < 0) {
+		/* Structure invalid, re-initialize */
+		ramtop.signature = RAMTOP_SIGNATURE;
+		ramtop.addr = 0;
+	}
+
+	/* Update ramtop if required */
+	if (ramtop.addr == addr)
+		return;
+
+	ramtop.addr = addr;
+
+	/* Write the new top_of_ram address to CMOS */
+	ramtop_cmos_write(&ramtop);
+
+	printk(BIOS_DEBUG, "Updated the RAMTOP address into CMOS 0x%x\n", ramtop.addr);
+}
+
+static uint32_t get_ramtop_addr(void)
+{
+	struct ramtop_table ramtop;
+
+	if (ramtop_cmos_read(&ramtop) < 0)
+		return 0;
+
+	return ramtop.addr;
+}
+
+/* Early caching of top_of_ram region */
+void early_ramtop_enable_cache_range(void)
+{
+	uint32_t ramtop = get_ramtop_addr();
+	if (!ramtop)
+		return;
+
+	int mtrr = get_free_var_mtrr();
+	if (mtrr == -1) {
+		printk(BIOS_WARNING, "ramtop_table update failure due to no free MTRR available!\n");
+		return;
+	}
+	/*
+	 * We need to make sure late romstage (including FSP-M post mem) will be run
+	 * cached. Caching 16MB below ramtop is a safe to cover late romstage.
+	 */
+	set_var_mtrr(mtrr, ramtop - 16 * MiB, 16 * MiB, MTRR_TYPE_WRBACK);
+}

src/soc/intel/common/basecode/tom/Makefile.inc

@@ -1,2 +0,0 @@
-## SPDX-License-Identifier: GPL-2.0-only
-romstage-$(CONFIG_SOC_INTEL_COMMON_BASECODE_TOM) += tom.c

src/soc/intel/common/basecode/tom/tom.c

@@ -1,127 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-or-later */
-
-#include <console/console.h>
-#include <cpu/x86/mtrr.h>
-#include <ip_checksum.h>
-#include <intelbasecode/tom.h>
-#include <pc80/mc146818rtc.h>
-#include <stdint.h>
-
-/* We need a region in CMOS to store the TOM address */
-
-#define TOM_SIGNATURE   0x5F544F4D /* '_TOM' */
-
-#define TOM_CMOS_OFFSET 0x64
-
-/*
- * Address of the tom_cmos_offset byte in CMOS. Should be reserved
- * in mainboards' cmos.layout and not covered by checksum.
- */
-
-#if CONFIG(USE_OPTION_TABLE)
-#include "option_table.h"
-#if CMOS_VSTART_tom_cmos_offset != TOM_CMOS_OFFSET * 8
-#error "CMOS start for TOM_CMOS is not correct, check your cmos.layout"
-#endif
-#if CMOS_VLEN_tom_cmos_offset != 12
-#error "CMOS length for TOM_CMOS bytes are not correct, check your cmos.layout"
-#endif
-#endif
-
-struct tom_table {
-	uint32_t signature;
-	uint32_t addr;
-	uint16_t checksum;
-} __packed;
-
-/* Read and validate tom_table structure from CMOS */
-static int tom_cmos_read(struct tom_table *tom)
-{
-	u8 i, *p;
-	u16 csum;
-
-	for (p = (u8 *)tom, i = 0; i < sizeof(*tom); i++, p++)
-		*p = cmos_read(TOM_CMOS_OFFSET + i);
-
-	/* Verify signature */
-	if (tom->signature != TOM_SIGNATURE) {
-		printk(BIOS_DEBUG, "tom_table invalid signature\n");
-		return -1;
-	}
-
-	/* Verify checksum over signature and counter only */
-	csum = compute_ip_checksum(tom, offsetof(struct tom_table, checksum));
-
-	if (csum != tom->checksum) {
-		printk(BIOS_DEBUG, "tom_table checksum mismatch\n");
-		return -1;
-	}
-
-	return 0;
-}
-
-/* Write tom_table structure to CMOS */
-static void tom_cmos_write(struct tom_table *tom)
-{
-	u8 i, *p;
-
-	/* Checksum over signature and counter only */
-	tom->checksum = compute_ip_checksum(
-		tom, offsetof(struct tom_table, checksum));
-
-	for (p = (u8 *)tom, i = 0; i < sizeof(*tom); i++, p++)
-		cmos_write(*p, TOM_CMOS_OFFSET + i);
-}
-
-/* Update the TOM if required based on the input TOM address */
-void update_tom(uint32_t addr)
-{
-	struct tom_table tom;
-
-	/* Read and increment boot count */
-	if (tom_cmos_read(&tom) < 0) {
-		/* Structure invalid, re-initialize */
-		tom.signature = TOM_SIGNATURE;
-		tom.addr = 0;
-	}
-
-	/* Update TOM if required */
-	if (tom.addr == addr)
-		return;
-
-	tom.addr = addr;
-
-	/* Write the new count to CMOS */
-	tom_cmos_write(&tom);
-
-	printk(BIOS_DEBUG, "Updated the TOM address into CMOS 0x%x\n", tom.addr);
-}
-
-static uint32_t get_tom_addr(void)
-{
-	struct tom_table tom;
-
-	if (tom_cmos_read(&tom) < 0)
-		return 0;
-
-	return tom.addr;
-}
-
-/* Early caching of TOM region */
-void early_tom_enable_cache_range(void)
-{
-	uint32_t tom = get_tom_addr();
-	if (!tom)
-		return;
-
-	int mtrr = get_free_var_mtrr();
-	if (mtrr == -1) {
-		printk(BIOS_WARNING, "tom_table update failure due to no free MTRR available!\n");
-		return;
-	}
-	/*
-	 * We need to make sure late romstage (including FSP-M post mem) will be run
-	 * cached. Caching 16MB below TOM is a safe to cover late romstage.
-	 */
-	set_var_mtrr(mtrr, tom - 16 * MiB, 16 * MiB, MTRR_TYPE_WRBACK);
-}

src/soc/intel/common/block/systemagent/memmap.c

@@ -6,7 +6,7 @@
 #include <console/console.h>
 #include <cpu/x86/mtrr.h>
 #include <cpu/x86/smm.h>
-#include <intelbasecode/tom.h>
+#include <intelbasecode/ramtop.h>
 #include <intelblocks/fast_spi.h>
 #include <intelblocks/systemagent.h>
 #include <types.h>
@@ -71,11 +71,11 @@ void fill_postcar_frame(struct postcar_frame *pcf)
 	printk(BIOS_DEBUG, "top_of_ram = 0x%lx\n", top_of_ram);
 
 	/*
-	 * Store the top_of_ram (TOM) into the CMOS if SOC_INTEL_COMMON_BASECODE_TOM
+	 * Store the top_of_ram (ramtop) into the CMOS if SOC_INTEL_COMMON_BASECODE_RAMTOP
 	 * config is enabled.
 	 */
-	if (ENV_ROMSTAGE && CONFIG(SOC_INTEL_COMMON_BASECODE_TOM))
+	if (ENV_ROMSTAGE && CONFIG(SOC_INTEL_COMMON_BASECODE_RAMTOP))
-		update_tom(top_of_ram);
+		update_ramtop(top_of_ram);
 
 	postcar_frame_add_mtrr(pcf, top_of_ram - 16 * MiB, 16 * MiB, MTRR_TYPE_WRBACK);
 

src/soc/intel/meteorlake/Kconfig

@@ -84,7 +84,7 @@ config CPU_SPECIFIC_OPTIONS
 	select SOC_INTEL_COMMON_BLOCK_XHCI
 	select SOC_INTEL_COMMON_BLOCK_XHCI_ELOG
 	select SOC_INTEL_COMMON_BASECODE
-	select SOC_INTEL_COMMON_BASECODE_TOM
+	select SOC_INTEL_COMMON_BASECODE_RAMTOP
 	select SOC_INTEL_COMMON_FSP_RESET
 	select SOC_INTEL_COMMON_PCH_CLIENT
 	select SOC_INTEL_COMMON_RESET