From f41d2430bbd6b64ee934915a1856fa406677d55e Mon Sep 17 00:00:00 2001 From: Paul Burton Date: Fri, 2 Jun 2017 12:29:52 -0700 Subject: MIPS: generic/yamon-dt: Support > 256MB of RAM YAMON can expose more than 256MB of RAM to Linux on Malta by passing an ememsize environment variable with the full size, but the kernel then needs to be careful to choose the corresponding physical memory regions, avoiding the IO memory window. This is platform dependent, and on Malta it also depends on the memory layout which varies between system controllers. Extend yamon_dt_amend_memory() to generically handle this by taking [e]memsize bytes of memory from an array of memory regions passed in as a new parameter. Board code provides this array as appropriate depending on its own memory map. [paul.burton@imgtec.com: SEAD-3 supports 384MB DDR from 0] Signed-off-by: James Hogan Signed-off-by: Paul Burton Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/16182/ Signed-off-by: Ralf Baechle --- arch/mips/generic/yamon-dt.c | 92 ++++++++++++++++++++++++++++++++++---------- 1 file changed, 71 insertions(+), 21 deletions(-) (limited to 'arch/mips/generic/yamon-dt.c') diff --git a/arch/mips/generic/yamon-dt.c b/arch/mips/generic/yamon-dt.c index 9a0c8da5a796..8e36a5baaa7e 100644 --- a/arch/mips/generic/yamon-dt.c +++ b/arch/mips/generic/yamon-dt.c @@ -17,6 +17,9 @@ #include #include +#include + +#define MAX_MEM_ARRAY_ENTRIES 2 __init int yamon_dt_append_cmdline(void *fdt) { @@ -43,23 +46,64 @@ __init int yamon_dt_append_cmdline(void *fdt) return 0; } -__init int yamon_dt_append_memory(void *fdt) +static unsigned int __init gen_fdt_mem_array( + const struct yamon_mem_region *regions, + __be32 *mem_array, + unsigned int max_entries, + unsigned long memsize) +{ + const struct yamon_mem_region *mr; + unsigned long size; + unsigned int entries = 0; + + for (mr = regions; mr->size && memsize; ++mr) { + if (entries >= max_entries) { + pr_warn("Number of regions exceeds max %u\n", + max_entries); + break; + } + + /* How much of the remaining RAM fits in the next region? */ + size = min_t(unsigned long, memsize, mr->size); + memsize -= size; + + /* Emit a memory region */ + *(mem_array++) = cpu_to_be32(mr->start); + *(mem_array++) = cpu_to_be32(size); + ++entries; + + /* Discard the next mr->discard bytes */ + memsize -= min_t(unsigned long, memsize, mr->discard); + } + return entries; +} + +__init int yamon_dt_append_memory(void *fdt, + const struct yamon_mem_region *regions) { unsigned long phys_memsize, memsize; - __be32 mem_array[2]; - int err, mem_off; - char *var; + __be32 mem_array[2 * MAX_MEM_ARRAY_ENTRIES]; + unsigned int mem_entries; + int i, err, mem_off; + char *var, param_name[10], *var_names[] = { + "ememsize", "memsize", + }; /* find memory size from the bootloader environment */ - var = fw_getenv("memsize"); - if (var) { + for (i = 0; i < ARRAY_SIZE(var_names); i++) { + var = fw_getenv(var_names[i]); + if (!var) + continue; + err = kstrtoul(var, 0, &phys_memsize); - if (err) { - pr_err("Failed to read memsize env variable '%s'\n", - var); - return -EINVAL; - } - } else { + if (!err) + break; + + pr_warn("Failed to read the '%s' env variable '%s'\n", + var_names[i], var); + } + + if (!phys_memsize) { pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n"); phys_memsize = 32 << 20; } @@ -68,9 +112,14 @@ __init int yamon_dt_append_memory(void *fdt) memsize = phys_memsize; /* allow the user to override the usable memory */ - var = strstr(arcs_cmdline, "memsize="); - if (var) - memsize = memparse(var + strlen("memsize="), NULL); + for (i = 0; i < ARRAY_SIZE(var_names); i++) { + snprintf(param_name, sizeof(param_name), "%s=", var_names[i]); + var = strstr(arcs_cmdline, param_name); + if (!var) + continue; + + memsize = memparse(var + strlen(param_name), NULL); + } /* if the user says there's more RAM than we thought, believe them */ phys_memsize = max_t(unsigned long, phys_memsize, memsize); @@ -90,18 +139,19 @@ __init int yamon_dt_append_memory(void *fdt) return err; } - mem_array[0] = 0; - mem_array[1] = cpu_to_be32(phys_memsize); - err = fdt_setprop(fdt, mem_off, "reg", mem_array, sizeof(mem_array)); + mem_entries = gen_fdt_mem_array(regions, mem_array, + MAX_MEM_ARRAY_ENTRIES, phys_memsize); + err = fdt_setprop(fdt, mem_off, "reg", + mem_array, mem_entries * 2 * sizeof(mem_array[0])); if (err) { pr_err("Unable to set memory regs property: %d\n", err); return err; } - mem_array[0] = 0; - mem_array[1] = cpu_to_be32(memsize); + mem_entries = gen_fdt_mem_array(regions, mem_array, + MAX_MEM_ARRAY_ENTRIES, memsize); err = fdt_setprop(fdt, mem_off, "linux,usable-memory", - mem_array, sizeof(mem_array)); + mem_array, mem_entries * 2 * sizeof(mem_array[0])); if (err) { pr_err("Unable to set linux,usable-memory property: %d\n", err); return err; -- cgit v1.2.3