MIPS: cmdline: Add support for 'memmap' parameter

Implement support for parsing 'memmap' kernel command line parameter.

This patch covers parsing of the following two formats for 'memmap'
parameter values:

  - nn[KMG]@ss[KMG]
  - nn[KMG]$ss[KMG]

  ([KMG] = K M or G (kilo, mega, giga))

These two allowed formats for parameter value are already documented
in file kernel-parameters.txt in Documentation/admin-guide folder.
Some architectures already support them, but Mips did not prior to
this patch.

Excerpt from Documentation/admin-guide/kernel-parameters.txt:

memmap=nn[KMG]@ss[KMG]
    [KNL] Force usage of a specific region of memory.
    Region of memory to be used is from ss to ss+nn.

memmap=nn[KMG]$ss[KMG]
    Mark specific memory as reserved.
    Region of memory to be reserved is from ss to ss+nn.
    Example: Exclude memory from 0x18690000-0x1869ffff
        memmap=64K$0x18690000
        or
        memmap=0x10000$0x18690000

There is no need to update this documentation file with respect to
this patch.

Signed-off-by: Miodrag Dinic <miodrag.dinic@imgtec.com>
Signed-off-by: Goran Ferenc <goran.ferenc@imgtec.com>
Signed-off-by: Aleksandar Markovic <aleksandar.markovic@imgtec.com>
Cc: James.Hogan@imgtec.com
Cc: Paul.Burton@imgtec.com
Cc: Raghu.Gandham@imgtec.com
Cc: Leonid.Yegoshin@imgtec.com
Cc: Douglas.Leung@imgtec.com
Cc: Petar.Jovanovic@imgtec.com
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16508/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

diff --git a/arch/mips/kernel/setup.c b/arch/mips/kernel/setup.c
index 01d1dbde5fbf1eb2e19c11074fdd5ed7d5a89ec3..fe3939726765155e08d6b4b6e8b678f334b9756f 100644 (file)
--- a/arch/mips/kernel/setup.c
+++ b/arch/mips/kernel/setup.c
@@ -670,6 +670,46 @@ static int __init early_parse_mem(char *p)
 }
 early_param("mem", early_parse_mem);
 
+static int __init early_parse_memmap(char *p)
+{
+       char *oldp;
+       u64 start_at, mem_size;
+
+       if (!p)
+               return -EINVAL;
+
+       if (!strncmp(p, "exactmap", 8)) {
+               pr_err("\"memmap=exactmap\" invalid on MIPS\n");
+               return 0;
+       }
+
+       oldp = p;
+       mem_size = memparse(p, &p);
+       if (p == oldp)
+               return -EINVAL;
+
+       if (*p == '@') {
+               start_at = memparse(p+1, &p);
+               add_memory_region(start_at, mem_size, BOOT_MEM_RAM);
+       } else if (*p == '#') {
+               pr_err("\"memmap=nn#ss\" (force ACPI data) invalid on MIPS\n");
+               return -EINVAL;
+       } else if (*p == '$') {
+               start_at = memparse(p+1, &p);
+               add_memory_region(start_at, mem_size, BOOT_MEM_RESERVED);
+       } else {
+               pr_err("\"memmap\" invalid format!\n");
+               return -EINVAL;
+       }
+
+       if (*p == '\0') {
+               usermem = 1;
+               return 0;
+       } else
+               return -EINVAL;
+}
+early_param("memmap", early_parse_memmap);
+
 #ifdef CONFIG_PROC_VMCORE
 unsigned long setup_elfcorehdr, setup_elfcorehdr_size;
 static int __init early_parse_elfcorehdr(char *p)