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MIPS: ralink: mt7621: add memory detection support

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mt7621 has the following memory map:
0x0-0x1c000000: lower 448m memory
0x1c000000-0x2000000: peripheral registers
0x20000000-0x2400000: higher 64m memory

detect_memory_region in arch/mips/kernel/setup.c only adds the first
memory region and isn't suitable for 512m memory detection because
it may accidentally read the memory area for peripheral registers.

This commit adds memory detection capability for mt7621:
  1. Add the highmem area when 512m is detected.
  2. Guard memcmp from accessing peripheral registers:
     This only happens when a user decided to change kernel load address
     to 256m or higher address. Since this is a quite unusual case, we
     just skip 512m testing and return 256m as memory size.

Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
[Minor commit message reword, make mt7621_memory_detect static]
Signed-off-by: Ilya Lipnitskiy <ilya.lipnitskiy@gmail.com>
Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
This commit is contained in:
Chuanhong Guo 2021-03-26 22:38:40 -07:00 committed by Thomas Bogendoerfer
parent 8eb6eb4882
commit 139c949f7f
4 changed files with 32 additions and 7 deletions
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7
arch/mips/include/asm/mach-ralink/mt7621.h
View File

@ -24,9 +24,10 @@
#define CHIP_REV_VER_SHIFT 8
#define CHIP_REV_ECO_MASK 0xf
#define MT7621_DRAM_BASE 0x0
#define MT7621_DDR2_SIZE_MIN 32
#define MT7621_DDR2_SIZE_MAX 256
#define MT7621_LOWMEM_BASE 0x0
#define MT7621_LOWMEM_MAX_SIZE 0x1C000000
#define MT7621_HIGHMEM_BASE 0x20000000
#define MT7621_HIGHMEM_SIZE 0x4000000
#define MT7621_CHIP_NAME0 0x3637544D
#define MT7621_CHIP_NAME1 0x20203132

1
arch/mips/ralink/common.h
View File

@ -17,6 +17,7 @@ struct ralink_soc_info {
unsigned long mem_size;
unsigned long mem_size_min;
unsigned long mem_size_max;
void (*mem_detect)(void);
};
extern struct ralink_soc_info soc_info;

29
arch/mips/ralink/mt7621.c
View File

@ -9,7 +9,9 @@
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/sys_soc.h>
#include <linux/memblock.h>
#include <asm/bootinfo.h>
#include <asm/mipsregs.h>
#include <asm/smp-ops.h>
#include <asm/mips-cps.h>
@ -49,6 +51,8 @@
#define MT7621_GPIO_MODE_SDHCI_SHIFT 18
#define MT7621_GPIO_MODE_SDHCI_GPIO 1
static void *detect_magic __initdata = detect_memory_region;
static struct rt2880_pmx_func uart1_grp[] = { FUNC("uart1", 0, 1, 2) };
static struct rt2880_pmx_func i2c_grp[] = { FUNC("i2c", 0, 3, 2) };
static struct rt2880_pmx_func uart3_grp[] = {
@ -110,6 +114,26 @@ phys_addr_t mips_cpc_default_phys_base(void)
panic("Cannot detect cpc address");
}
static void __init mt7621_memory_detect(void)
{
void *dm = &detect_magic;
phys_addr_t size;
for (size = 32 * SZ_1M; size < 256 * SZ_1M; size <<= 1) {
if (!__builtin_memcmp(dm, dm + size, sizeof(detect_magic)))
break;
}
if ((size == 256 * SZ_1M) &&
(CPHYSADDR(dm + size) < MT7621_LOWMEM_MAX_SIZE) &&
__builtin_memcmp(dm, dm + size, sizeof(detect_magic))) {
memblock_add(MT7621_LOWMEM_BASE, MT7621_LOWMEM_MAX_SIZE);
memblock_add(MT7621_HIGHMEM_BASE, MT7621_HIGHMEM_SIZE);
} else {
memblock_add(MT7621_LOWMEM_BASE, size);
}
}
void __init ralink_of_remap(void)
{
rt_sysc_membase = plat_of_remap_node("mtk,mt7621-sysc");
@ -194,10 +218,7 @@ void __init prom_soc_init(struct ralink_soc_info *soc_info)
(rev >> CHIP_REV_VER_SHIFT) & CHIP_REV_VER_MASK,
(rev & CHIP_REV_ECO_MASK));
soc_info->mem_size_min = MT7621_DDR2_SIZE_MIN;
soc_info->mem_size_max = MT7621_DDR2_SIZE_MAX;
soc_info->mem_base = MT7621_DRAM_BASE;
soc_info->mem_detect = mt7621_memory_detect;
rt2880_pinmux_data = mt7621_pinmux_data;
soc_dev_init(soc_info, rev);

2
arch/mips/ralink/of.c
View File

@ -78,6 +78,8 @@ void __init plat_mem_setup(void)
of_scan_flat_dt(early_init_dt_find_memory, NULL);
if (memory_dtb)
of_scan_flat_dt(early_init_dt_scan_memory, NULL);
else if (soc_info.mem_detect)
soc_info.mem_detect();
else if (soc_info.mem_size)
memblock_add(soc_info.mem_base, soc_info.mem_size * SZ_1M);
else