[PATCH v2 7/8] hw/mips/fuloong2e: Add highmem support

[Jiaxun Yang <jiaxun.yang@flygoat.com>]

highmem started from 0x20000000.
Now we can have up to 2G RAM.

Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
---
v2: Handle SPD for dual DIMM correctly.
---
 hw/mips/fuloong2e.c | 61 ++++++++++++++++++++++++++++++++++++---------
 1 file changed, 49 insertions(+), 12 deletions(-)

diff --git a/hw/mips/fuloong2e.c b/hw/mips/fuloong2e.c
index 2744b211fd..8a4bebe066 100644
--- a/hw/mips/fuloong2e.c
+++ b/hw/mips/fuloong2e.c
@@ -56,6 +56,7 @@
 /* Fuloong 2e has a 512k flash: Winbond W39L040AP70Z */
 #define BIOS_SIZE               (512 * KiB)
 #define MAX_IDE_BUS             2
+#define HIGHMEM_START           0x20000000
 
 /*
  * PMON is not part of qemu and released with BSD license, anyone
@@ -71,7 +72,8 @@
 #define FULOONG2E_RTL8139_SLOT    7
 
 static struct _loaderparams {
-    int ram_size;
+    int ram_low_size;
+    int ram_high_size;
     const char *kernel_filename;
     const char *kernel_cmdline;
     const char *initrd_filename;
@@ -128,14 +130,14 @@ static uint64_t load_kernel(MIPSCPU *cpu)
         initrd_size = get_image_size(loaderparams.initrd_filename);
         if (initrd_size > 0) {
             initrd_offset = ROUND_UP(kernel_high, INITRD_PAGE_SIZE);
-            if (initrd_offset + initrd_size > loaderparams.ram_size) {
+            if (initrd_offset + initrd_size > loaderparams.ram_low_size) {
                 error_report("memory too small for initial ram disk '%s'",
                              loaderparams.initrd_filename);
                 exit(1);
             }
             initrd_size = load_image_targphys(loaderparams.initrd_filename,
                                               initrd_offset,
-                                              loaderparams.ram_size - initrd_offset);
+                                              loaderparams.ram_low_size - initrd_offset);
         }
         if (initrd_size == (target_ulong) -1) {
             error_report("could not load initial ram disk '%s'",
@@ -160,7 +162,11 @@ static uint64_t load_kernel(MIPSCPU *cpu)
 
     /* Setup minimum environment variables */
     prom_set(prom_buf, index++, "cpuclock=%u", clock_get_hz(cpu->clock));
-    prom_set(prom_buf, index++, "memsize=%"PRIi64, loaderparams.ram_size / MiB);
+    prom_set(prom_buf, index++, "memsize=%"PRIi64, loaderparams.ram_low_size / MiB);
+    if (loaderparams.ram_high_size > 0) {
+            prom_set(prom_buf, index++, "highmemsize=%"PRIi64,
+                    loaderparams.ram_high_size / MiB);
+    }
     prom_set(prom_buf, index++, NULL);
 
     rom_add_blob_fixed("prom", prom_buf, prom_size, ENVP_PADDR);
@@ -186,7 +192,7 @@ static void write_bootloader(CPUMIPSState *env, uint8_t *base,
     p = (uint32_t *)(base + 0x040);
 
     bl_gen_jump_kernel(&p, ENVP_VADDR - 64, 2, ENVP_VADDR,
-                       ENVP_VADDR + 8, loaderparams.ram_size,
+                       ENVP_VADDR + 8, loaderparams.ram_low_size,
                        kernel_addr);
 }
 
@@ -258,8 +264,11 @@ static void mips_fuloong2e_init(MachineState *machine)
     const char *kernel_filename = machine->kernel_filename;
     const char *kernel_cmdline = machine->kernel_cmdline;
     const char *initrd_filename = machine->initrd_filename;
+    ram_addr_t ram_low_size, ram_high_size = 0;
     char *filename;
     MemoryRegion *address_space_mem = get_system_memory();
+    MemoryRegion *ram_low_alias = g_new(MemoryRegion, 1);
+    MemoryRegion *ram_high_alias;
     MemoryRegion *bios = g_new(MemoryRegion, 1);
     long bios_size;
     uint8_t *spd_data;
@@ -282,12 +291,31 @@ static void mips_fuloong2e_init(MachineState *machine)
 
     qemu_register_reset(main_cpu_reset, cpu);
 
-    /* TODO: support more than 256M RAM as highmem */
-    if (machine->ram_size != 256 * MiB) {
-        error_report("Invalid RAM size, should be 256MB");
+    if (machine->ram_size > 2 * GiB) {
+        error_report("Too much memory for this machine: %" PRId64 "MB,"
+                     " maximum 2048MB", machine->ram_size / MiB);
         exit(EXIT_FAILURE);
     }
-    memory_region_add_subregion(address_space_mem, 0, machine->ram);
+
+    ram_low_size = MIN(machine->ram_size, 256 * MiB);
+
+    memory_region_init_alias(ram_low_alias, NULL,
+                            "ram_low_alias",
+                            machine->ram, 0,
+                            ram_low_size);
+    memory_region_add_subregion(address_space_mem, 0,
+                                ram_low_alias);
+
+    if (machine->ram_size > 256 * MiB) {
+        ram_high_alias = g_new(MemoryRegion, 1);
+        ram_high_size = machine->ram_size - ram_low_size;
+        memory_region_init_alias(ram_high_alias, NULL,
+                                "ram_high_alias",
+                                machine->ram, ram_low_size,
+                                ram_high_size);
+        memory_region_add_subregion(address_space_mem, HIGHMEM_START,
+                                    ram_high_alias);
+    }
 
     /* Boot ROM */
     memory_region_init_rom(bios, NULL, "fuloong2e.bios", BIOS_SIZE,
@@ -300,7 +328,8 @@ static void mips_fuloong2e_init(MachineState *machine)
      */
 
     if (kernel_filename) {
-        loaderparams.ram_size = machine->ram_size;
+        loaderparams.ram_low_size = ram_low_size;
+        loaderparams.ram_high_size = ram_high_size;
         loaderparams.kernel_filename = kernel_filename;
         loaderparams.kernel_cmdline = kernel_cmdline;
         loaderparams.initrd_filename = initrd_filename;
@@ -345,8 +374,16 @@ static void mips_fuloong2e_init(MachineState *machine)
     }
 
     /* Populate SPD eeprom data */
-    spd_data = spd_data_generate(DDR, machine->ram_size);
-    smbus_eeprom_init_one(smbus, 0x50, spd_data);
+    if (machine->ram_size <= 1 * GiB) {
+        /* It supports maxium of 1 GiB per DIMM */
+        spd_data = spd_data_generate(DDR, machine->ram_size);
+        smbus_eeprom_init_one(smbus, 0x50, spd_data);
+    } else {
+        /* Split to dual DIMM for more than 1 GiB  */
+        spd_data = spd_data_generate(DDR, machine->ram_size / 2);
+        smbus_eeprom_init_one(smbus, 0x50, spd_data);
+        smbus_eeprom_init_one(smbus, 0x51, spd_data);
+    }
 
     mc146818_rtc_init(isa_bus, 2000, NULL);
 
-- 
2.29.2