From 24c3d2f342edbc10fee9f8ab9e0a033393686543 Mon Sep 17 00:00:00 2001 From: Anton Vorontsov Date: Fri, 11 May 2012 17:17:54 -0700 Subject: [PATCH] staging: android: persistent_ram: Make it possible to use memory outside of bootmem This includes devices' memory (e.g. framebuffers or memory mapped EEPROMs on a local bus), as well as the normal RAM that we don't use for the main memory. For the normal (but unused) ram we could use kmaps, but this assumes highmem support, so we don't bother and just use the memory via ioremap. As a side effect, the following hack is possible: when used together with pstore_ram (new ramoops) module, we can limit the normal RAM region with mem= and then point ramoops to use the rest of the memory, e.g. mem=128M ramoops.mem_address=0x8000000 Sure, we could just reserve the region with memblock_reserve() early in the arch/ code, and then register a pstore_ram platform device pointing to the reserved region. It's still a viable option if platform wants to do so. Also, we might want to use IO accessors in case of a real device, but for now we don't bother (the old ramoops wasn't using it either, so at least we don't make things worse). Signed-off-by: Anton Vorontsov Signed-off-by: Greg Kroah-Hartman --- drivers/staging/android/persistent_ram.c | 18 +++++++++++++++++- 1 file changed, 17 insertions(+), 1 deletion(-) diff --git a/drivers/staging/android/persistent_ram.c b/drivers/staging/android/persistent_ram.c index ab8bff19dca0..c16d7c2b1d97 100644 --- a/drivers/staging/android/persistent_ram.c +++ b/drivers/staging/android/persistent_ram.c @@ -23,6 +23,7 @@ #include #include #include +#include #include "persistent_ram.h" struct persistent_ram_buffer { @@ -349,10 +350,25 @@ static void *persistent_ram_vmap(phys_addr_t start, size_t size) return vaddr; } +static void *persistent_ram_iomap(phys_addr_t start, size_t size) +{ + if (!request_mem_region(start, size, "persistent_ram")) { + pr_err("request mem region (0x%llx@0x%llx) failed\n", + (unsigned long long)size, (unsigned long long)start); + return NULL; + } + + return ioremap(start, size); +} + static int persistent_ram_buffer_map(phys_addr_t start, phys_addr_t size, struct persistent_ram_zone *prz) { - prz->vaddr = persistent_ram_vmap(start, size); + if (pfn_valid(start >> PAGE_SHIFT)) + prz->vaddr = persistent_ram_vmap(start, size); + else + prz->vaddr = persistent_ram_iomap(start, size); + if (!prz->vaddr) { pr_err("%s: Failed to map 0x%llx pages at 0x%llx\n", __func__, (unsigned long long)size, (unsigned long long)start);