CBMEM: Clarify CBMEM_TOP_BACKUP function usage

The deprecated LATE_CBMEM_INIT function is renamed:
  set_top_of_ram -> set_late_cbmem_top

Obscure term top_of_ram is replaced:
  backup_top_of_ram -> backup_top_of_low_cacheable
  get_top_of_ram -> restore_top_of_low_cacheable

New function that always resolves to CBMEM top boundary, with
or without SMM, is named restore_cbmem_top().

Change-Id: I61d20f94840ad61e9fd55976e5aa8c27040b8fb7
Signed-off-by: Kyösti Mälkki <kyosti.malkki@gmail.com>
Reviewed-on: https://review.coreboot.org/19377
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Philippe Mathieu-Daudé <philippe.mathieu.daude@gmail.com>

src/arch/x86/cbmem.c

@@ -18,13 +18,13 @@
 
 #if IS_ENABLED(CONFIG_LATE_CBMEM_INIT)
 
-void __attribute__((weak)) backup_top_of_ram(uint64_t ramtop)
+void __attribute__((weak)) backup_top_of_low_cacheable(uintptr_t ramtop)
 {
 	/* Do nothing. Chipset may have implementation to save ramtop in NVRAM.
 	 */
 }
 
-unsigned long __attribute__((weak)) get_top_of_ram(void)
+uintptr_t __attribute__((weak)) restore_top_of_low_cacheable(void)
 {
 	return 0;
 }
@@ -33,29 +33,34 @@ unsigned long __attribute__((weak)) get_top_of_ram(void)
 
 #if IS_ENABLED(CONFIG_CBMEM_TOP_BACKUP)
 
-static void *ramtop_pointer;
+static void *cbmem_top_backup;
 
-void set_top_of_ram(uint64_t ramtop)
+void set_late_cbmem_top(uintptr_t ramtop)
 {
-	backup_top_of_ram(ramtop);
+	backup_top_of_low_cacheable(ramtop);
 	if (ENV_RAMSTAGE)
-		ramtop_pointer = (void *)(uintptr_t)ramtop;
+		cbmem_top_backup = (void *)ramtop;
+}
+
+/* Top of CBMEM is at highest usable DRAM address below 4GiB. */
+uintptr_t __attribute__((weak)) restore_cbmem_top(void)
+{
+	return restore_top_of_low_cacheable();
 }
 
 void *cbmem_top(void)
 {
-	/* Top of cbmem is at lowest usable DRAM address below 4GiB. */
-	uintptr_t ramtop;
+	uintptr_t top_backup;
 
-	if (ENV_RAMSTAGE && ramtop_pointer != NULL)
-		return ramtop_pointer;
+	if (ENV_RAMSTAGE && cbmem_top_backup != NULL)
+		return cbmem_top_backup;
 
-	ramtop = get_top_of_ram();
+	top_backup = restore_cbmem_top();
 
 	if (ENV_RAMSTAGE)
-		ramtop_pointer = (void *)ramtop;
+		cbmem_top_backup = (void *)top_backup;
 
-	return (void *)ramtop;
+	return (void *)top_backup;
 }
 
 #endif /* CBMEM_TOP_BACKUP */

src/cpu/amd/mtrr/amd_mtrr.c

@@ -80,7 +80,7 @@ static void setup_ap_ramtop(void)
 void add_uma_resource_below_tolm(struct device *nb, int idx)
 {
 	uint32_t topmem = bsp_topmem();
-	uint32_t top_of_cacheable = get_top_of_ram();
+	uint32_t top_of_cacheable = restore_top_of_low_cacheable();
 
 	if (top_of_cacheable == topmem)
 		return;

src/include/cbmem.h

@@ -151,12 +151,15 @@ void cbmem_add_records_to_cbtable(struct lb_header *header);
  * value stored in nvram to enable early recovery on S3 path.
  */
 #if IS_ENABLED(CONFIG_ARCH_X86)
-/* Note that many of the current providers of get_top_of_ram() conditionally
- * return 0 when the sleep type is non S3. i.e. cold and warm boots would
- * return 0 from get_top_of_ram(). */
-unsigned long get_top_of_ram(void);
-void set_top_of_ram(uint64_t ramtop);
-void backup_top_of_ram(uint64_t ramtop);
+/* Note that with LATE_CBMEM_INIT, restore_top_of_low_cacheable()
+ * may conditionally return 0 when the sleep type is non S3,
+ * i.e. cold and warm boots would return NULL also for cbmem_top. */
+void backup_top_of_low_cacheable(uintptr_t ramtop);
+uintptr_t restore_top_of_low_cacheable(void);
+uintptr_t restore_cbmem_top(void);
+
+/* Deprecated, only use with LATE_CBMEM_INIT. */
+void set_late_cbmem_top(uintptr_t ramtop);
 #endif
 
 /*

src/northbridge/amd/agesa/agesawrapper.c

@@ -111,7 +111,7 @@ AGESA_STATUS agesawrapper_amdinitpost(void)
 	status = AmdInitPost(PostParams);
 	AGESA_EVENTLOG(status, &PostParams->StdHeader);
 
-	backup_top_of_ram(PostParams->MemConfig.Sub4GCacheTop);
+	backup_top_of_low_cacheable(PostParams->MemConfig.Sub4GCacheTop);
 
 	AmdReleaseStruct(&AmdParamStruct);
 

src/northbridge/amd/amdk8/northbridge.c

@@ -999,10 +999,10 @@ static void amdk8_domain_set_resources(device_t dev)
 	}
 
 #if CONFIG_GFXUMA
-	set_top_of_ram(uma_memory_base);
+	set_late_cbmem_top(uma_memory_base);
 	uma_resource(dev, 7, uma_memory_base >> 10, uma_memory_size >> 10);
 #else
-	set_top_of_ram(ramtop);
+	set_late_cbmem_top(ramtop);
 #endif
 	assign_resources(dev->link_list);
 

src/northbridge/amd/gx2/northbridge.c

@@ -286,7 +286,7 @@ static void pci_domain_set_resources(device_t dev)
 		ram_resource(dev, idx++, 0, 640);
 		ram_resource(dev, idx++, 768, tomk - 768);	/* Systop - 0xc0000 -> KB */
 
-		set_top_of_ram(tomk * 1024);
+		set_late_cbmem_top(tomk * 1024);
 	}
 
 	assign_resources(dev->link_list);

src/northbridge/amd/lx/northbridge.c

@@ -358,14 +358,14 @@ static void pci_domain_set_resources(device_t dev)
 
 	mc_dev = dev->link_list->children;
 	if (mc_dev) {
-		tomk = get_top_of_ram() / 1024;
+		tomk = restore_top_of_low_cacheable() / 1024;
 		/* Report the memory regions
 		   All memory up to systop except 0xa0000-0xbffff */
 		idx = 10;
 		ram_resource(dev, idx++, 0, 640);
 		ram_resource(dev, idx++, 768, tomk - 768);	// Systop - 0xc0000 -> KB
 
-		set_top_of_ram(tomk * 1024);
+		set_late_cbmem_top(tomk * 1024);
 	}
 
 	assign_resources(dev->link_list);

src/northbridge/amd/lx/northbridgeinit.c

@@ -710,7 +710,7 @@ static void setup_lx_cache(void)
 	wbinvd();
 }
 
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
 	uint32_t systop;
 	msr_t msr;

src/northbridge/amd/pi/agesawrapper.c

@@ -153,9 +153,9 @@ AGESA_STATUS agesawrapper_amdinitpost(void)
 	 * UMA may or may not be cacheable, so Sub4GCacheTop could be
 	 * higher than UmaBase. With UMA_NONE we see UmaBase==0. */
 	if (PostParams->MemConfig.UmaBase)
-		backup_top_of_ram(PostParams->MemConfig.UmaBase << 16);
+		backup_top_of_low_cacheable(PostParams->MemConfig.UmaBase << 16);
 	else
-		backup_top_of_ram(PostParams->MemConfig.Sub4GCacheTop);
+		backup_top_of_low_cacheable(PostParams->MemConfig.Sub4GCacheTop);
 
 	printk(
 			BIOS_SPEW,

src/northbridge/amd/pi/ramtop.c

@@ -19,13 +19,13 @@
 
 #define CBMEM_TOP_SCRATCHPAD 0x78
 
-void backup_top_of_ram(uint64_t ramtop)
+void backup_top_of_low_cacheable(uintptr_t ramtop)
 {
 	uint16_t top_cache = ramtop >> 16;
 	pci_write_config16(PCI_DEV(0,0,0), CBMEM_TOP_SCRATCHPAD, top_cache);
 }
 
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
 	uint16_t top_cache;
 	top_cache = pci_read_config16(PCI_DEV(0,0,0), CBMEM_TOP_SCRATCHPAD);

src/northbridge/intel/e7505/northbridge.c

@@ -92,7 +92,7 @@ static void pci_domain_set_resources(device_t dev)
 				(remaplimitk + 64*1024) - remapbasek);
 		}
 
-		set_top_of_ram(tolmk * 1024);
+		set_late_cbmem_top(tolmk * 1024);
 	}
 	assign_resources(dev->link_list);
 }

src/northbridge/intel/e7505/raminit.c

@@ -1892,10 +1892,10 @@ void e7505_mch_init(const struct mem_controller *memctrl)
 	sdram_enable(memctrl);
 }
 
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
 	u32 tolm = (pci_read_config16(MCHDEV, TOLM) & ~0x7ff) << 16;
-	return (unsigned long) tolm;
+	return tolm;
 }
 
 /**

src/northbridge/intel/i3100/northbridge.c

@@ -119,7 +119,7 @@ static void pci_domain_set_resources(device_t dev)
 				(remaplimitk + 64*1024) - remapbasek);
 		}
 
-		set_top_of_ram(tolmk * 1024);
+		set_late_cbmem_top(tolmk * 1024);
 	}
 	assign_resources(dev->link_list);
 }

src/northbridge/intel/i440bx/northbridge.c

@@ -67,7 +67,7 @@ static void i440bx_domain_set_resources(device_t dev)
 		ram_resource(dev, idx++, 0, 640);
 		ram_resource(dev, idx++, 768, tolmk - 768);
 
-		set_top_of_ram(tomk * 1024);
+		set_late_cbmem_top(tomk * 1024);
 	}
 	assign_resources(dev->link_list);
 }

src/northbridge/intel/i5000/northbridge.c

@@ -107,7 +107,7 @@ static void mc_read_resources(device_t dev)
 	resource->flags = IORESOURCE_MEM | IORESOURCE_RESERVE |
 	    IORESOURCE_FIXED | IORESOURCE_STORED | IORESOURCE_ASSIGNED;
 
-	set_top_of_ram(tolm);
+	set_late_cbmem_top(tolm);
 }
 
 static struct pci_operations intel_pci_ops = {

src/northbridge/intel/i82810/northbridge.c

@@ -118,7 +118,7 @@ static void pci_domain_set_resources(device_t dev)
 	ram_resource(dev, idx++, 768, tomk - 768);
 	uma_resource(dev, idx++, uma_memory_base >> 10, uma_memory_size >> 10);
 
-	set_top_of_ram(tomk_stolen * 1024);
+	set_late_cbmem_top(tomk_stolen * 1024);
 
 	assign_resources(dev->link_list);
 }

src/northbridge/intel/i82830/northbridge.c

@@ -87,7 +87,7 @@ static void pci_domain_set_resources(device_t dev)
 
 	assign_resources(dev->link_list);
 
-	set_top_of_ram(tomk_stolen * 1024);
+	set_late_cbmem_top(tomk_stolen * 1024);
 }
 
 static struct device_operations pci_domain_ops = {

src/northbridge/intel/i855/northbridge.c

@@ -101,7 +101,7 @@ static void pci_domain_set_resources(device_t dev)
 		/* ram_resource(dev, idx++, 1024, tolmk - 1024); */
 		ram_resource(dev, idx++, 768, tolmk - 768);
 
-		set_top_of_ram(tomk * 1024);
+		set_late_cbmem_top(tomk * 1024);
 	}
 	assign_resources(dev->link_list);
 }

src/northbridge/via/cn700/northbridge.c

@@ -130,7 +130,7 @@ static void pci_domain_set_resources(device_t dev)
 			tolmk = tomk;
 		}
 
-		set_top_of_ram((tolmk - CONFIG_VIDEO_MB * 1024) * 1024);
+		set_late_cbmem_top((tolmk - CONFIG_VIDEO_MB * 1024) * 1024);
 
 		/* Report the memory regions. */
 		idx = 10;

src/northbridge/via/cx700/northbridge.c

@@ -65,7 +65,7 @@ static void pci_domain_set_resources(device_t dev)
 		tolmk -= 1024;	// TOP 1M SM Memory
 	}
 
-	set_top_of_ram(tolmk * 1024);
+	set_late_cbmem_top(tolmk * 1024);
 
 	/* Report the memory regions */
 	idx = 10;

src/northbridge/via/vx900/early_vx900.c

@@ -18,10 +18,10 @@
 #include <arch/io.h>
 #include <console/console.h>
 
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
-	u16 reg_tom = pci_read_config8(MCU, 0x88);
-	return (((unsigned long)reg_tom) << 24) - (256 << 20);
+	u8 reg_tom = pci_read_config8(MCU, 0x88);
+	return (reg_tom << 24) - 256 * MiB;
 }
 
 /**

src/northbridge/via/vx900/northbridge.c

@@ -277,7 +277,7 @@ static void vx900_set_resources(device_t dev)
 	u64 tor = vx900_remap_above_4g(mcu, pci_tolm);
 	ram_resource(dev, idx++, RAM_4GB >> 10, (tor - RAM_4GB) >> 10);
 
-	set_top_of_ram(tolmk << 10);
+	set_late_cbmem_top(tolmk << 10);
 
 	printk(BIOS_DEBUG, "======================================================\n");
 	assign_resources(dev->link_list);

src/soc/dmp/vortex86ex/northbridge.c

@@ -97,7 +97,7 @@ static void pci_domain_set_resources(device_t dev)
 			 */
 			tolmk = tomk;
 
-		set_top_of_ram(tolmk * 1024);
+		set_late_cbmem_top(tolmk * 1024);
 
 		/* Report the memory regions */
 		idx = 10;

src/soc/intel/sch/northbridge.c

@@ -165,7 +165,7 @@ static void pci_domain_set_resources(device_t dev)
 
 	assign_resources(dev->link_list);
 
-	set_top_of_ram(tomk * 1024 - uma_memory_size - tseg_memory_base);
+	set_late_cbmem_top(tomk * 1024 - uma_memory_size - tseg_memory_base);
 }
 
 /*

src/soc/rdc/r8610/northbridge.c

@@ -60,7 +60,7 @@ static void cpu_pci_domain_set_resources(device_t dev)
 	ram_resource(dev, idx++, 0, 640);
 	ram_resource(dev, idx++, 768, tolmk - 768);
 
-	set_top_of_ram(tomk * 1024);
+	set_late_cbmem_top(tomk * 1024);
 
 	assign_resources(dev->link_list);
 }

src/southbridge/amd/agesa/hudson/ramtop.c

@@ -26,7 +26,7 @@ int acpi_get_sleep_type(void)
 	return (int)tmp;
 }
 
-void backup_top_of_ram(uint64_t ramtop)
+void backup_top_of_low_cacheable(uintptr_t ramtop)
 {
 	u32 dword = ramtop;
 	int nvram_pos = 0xf8, i; /* temp */
@@ -37,7 +37,7 @@ void backup_top_of_ram(uint64_t ramtop)
 	}
 }
 
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
 	uint32_t xdata = 0;
 	int xnvram_pos = 0xf8, xi;
@@ -47,5 +47,5 @@ unsigned long get_top_of_ram(void)
 		xdata |= inb(BIOSRAM_DATA) << (xi *8);
 		xnvram_pos++;
 	}
-	return (unsigned long) xdata;
+	return xdata;
 }

src/southbridge/amd/cimx/sb700/ramtop.c

@@ -18,7 +18,7 @@
 #include <cbmem.h>
 #include <southbridge/amd/cimx/cimx_util.h>
 
-void backup_top_of_ram(uint64_t ramtop)
+void backup_top_of_low_cacheable(uintptr_t ramtop)
 {
 	u32 dword = ramtop;
 	int nvram_pos = 0xfc, i;
@@ -29,7 +29,7 @@ void backup_top_of_ram(uint64_t ramtop)
 	}
 }
 
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
 	u32 xdata = 0;
 	int xnvram_pos = 0xfc, xi;
@@ -39,5 +39,5 @@ unsigned long get_top_of_ram(void)
 		xdata |= inb(BIOSRAM_DATA) << (xi *8);
 		xnvram_pos++;
 	}
-	return (unsigned long) xdata;
+	return xdata;
 }

src/southbridge/amd/cimx/sb800/ramtop.c

@@ -26,7 +26,7 @@ int acpi_get_sleep_type(void)
 	return (int)tmp;
 }
 
-void backup_top_of_ram(uint64_t ramtop)
+void backup_top_of_low_cacheable(uintptr_t ramtop)
 {
 	u32 dword = ramtop;
 	int nvram_pos = 0xf8, i; /* temp */
@@ -37,7 +37,7 @@ void backup_top_of_ram(uint64_t ramtop)
 	}
 }
 
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
 	u32 xdata = 0;
 	int xnvram_pos = 0xf8, xi;
@@ -47,5 +47,5 @@ unsigned long get_top_of_ram(void)
 		xdata |= inb(BIOSRAM_DATA) << (xi *8);
 		xnvram_pos++;
 	}
-	return (unsigned long) xdata;
+	return xdata;
 }

src/southbridge/amd/cimx/sb900/ramtop.c

@@ -18,7 +18,7 @@
 #include <cbmem.h>
 #include <southbridge/amd/cimx/cimx_util.h>
 
-void backup_top_of_ram(uint64_t ramtop)
+void backup_top_of_low_cacheable(uintptr_t ramtop)
 {
 	u32 dword = ramtop;
 	int nvram_pos = 0xf8, i; /* temp */
@@ -29,7 +29,7 @@ void backup_top_of_ram(uint64_t ramtop)
 	}
 }
 
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
 	u32 xdata = 0;
 	int xnvram_pos = 0xf8, xi;
@@ -39,5 +39,5 @@ unsigned long get_top_of_ram(void)
 		xdata |= inb(BIOSRAM_DATA) << (xi *8);
 		xnvram_pos++;
 	}
-	return (unsigned long) xdata;
+	return xdata;
 }

src/southbridge/amd/sb700/early_setup.c

@@ -860,8 +860,7 @@ void set_lpc_sticky_ctl(bool enable)
 	pmio_write(0xbb, byte);
 }
 
-#if IS_ENABLED(CONFIG_LATE_CBMEM_INIT)
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
 	uint32_t xdata = 0;
 	int xnvram_pos = 0xfc, xi;
@@ -873,8 +872,7 @@ unsigned long get_top_of_ram(void)
 		xdata |= inb(BIOSRAM_DATA) << (xi *8);
 		xnvram_pos++;
 	}
-	return (unsigned long) xdata;
+	return xdata;
 }
-#endif
 
 #endif

src/southbridge/amd/sb700/lpc.c

@@ -89,7 +89,7 @@ int acpi_get_sleep_type(void)
 	return ((tmp & (7 << 10)) >> 10);
 }
 
-void backup_top_of_ram(uint64_t ramtop)
+void backup_top_of_low_cacheable(uintptr_t ramtop)
 {
 	u32 dword = (u32) ramtop;
 	int nvram_pos = 0xfc, i;

src/southbridge/amd/sb800/early_setup.c

@@ -665,8 +665,7 @@ int acpi_get_sleep_type(void)
 	return ((tmp & (7 << 10)) >> 10);
 }
 
-#if IS_ENABLED(CONFIG_LATE_CBMEM_INIT)
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
 	uint32_t xdata = 0;
 	int xnvram_pos = 0xfc, xi;
@@ -678,8 +677,7 @@ unsigned long get_top_of_ram(void)
 		xdata |= inb(BIOSRAM_DATA) << (xi *8);
 		xnvram_pos++;
 	}
-	return (unsigned long) xdata;
+	return xdata;
 }
-#endif
 
 #endif

src/southbridge/via/k8t890/early_car.c

@@ -177,9 +177,9 @@ int s3_load_nvram_early(int size, u32 *old_dword, int nvram_pos)
 	return nvram_pos;
 }
 
-unsigned long get_top_of_ram(void)
+uintptr_t restore_top_of_low_cacheable(void)
 {
 	if (acpi_get_sleep_type() != 3)
 		return 0;
-	return (unsigned long) inl(K8T890_NVRAM_IO_BASE+K8T890_NVRAM_TOP_OF_RAM);
+	return inl(K8T890_NVRAM_IO_BASE+K8T890_NVRAM_TOP_OF_RAM);
 }

src/southbridge/via/k8t890/host_ctrl.c

@@ -110,12 +110,10 @@ static void host_ctrl_enable_k8m8xx(struct device *dev) {
 
 }
 
-#if IS_ENABLED(CONFIG_LATE_CBMEM_INIT)
-void backup_top_of_ram(uint64_t ramtop)
+void backup_top_of_low_cacheable(uintptr_t ramtop)
 {
-		outl((u32) ramtop, K8T890_NVRAM_IO_BASE+K8T890_NVRAM_TOP_OF_RAM);
+	outl((u32) ramtop, K8T890_NVRAM_IO_BASE+K8T890_NVRAM_TOP_OF_RAM);
 }
-#endif
 
 static struct pci_operations lops_pci = {
 	.set_subsystem = pci_dev_set_subsystem,