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authorRafał Miłecki <zajec5@gmail.com>2014-07-18 01:26:33 +0400
committerRalf Baechle <ralf@linux-mips.org>2014-07-31 01:27:02 +0400
commit6ee1d93455384cef8a0426effe85da241b525b63 (patch)
treeb3e66dbb882a5dbcdbcbc45cda66639d3141a5ca /arch/mips/bcm47xx/prom.c
parentd377732c8c9aac14ccb900b65678558b0fb8f0f3 (diff)
downloadlinux-6ee1d93455384cef8a0426effe85da241b525b63.tar.xz
MIPS: BCM47XX: Detect more then 128 MiB of RAM (HIGHMEM)
So far BCM47XX can only detect amount of HIGHMEM. It still requires adding (registering) and well-testing before enabling by default. Signed-off-by: Rafał Miłecki <zajec5@gmail.com> Acked-by: Hauke Mehrtens <hauke@hauke-m.de> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/7396/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'arch/mips/bcm47xx/prom.c')
-rw-r--r--arch/mips/bcm47xx/prom.c68
1 files changed, 67 insertions, 1 deletions
diff --git a/arch/mips/bcm47xx/prom.c b/arch/mips/bcm47xx/prom.c
index 1a03a2f43496..1b170bf5f7f0 100644
--- a/arch/mips/bcm47xx/prom.c
+++ b/arch/mips/bcm47xx/prom.c
@@ -51,6 +51,8 @@ __init void bcm47xx_set_system_type(u16 chip_id)
chip_id);
}
+static unsigned long lowmem __initdata;
+
static __init void prom_init_mem(void)
{
unsigned long mem;
@@ -87,6 +89,7 @@ static __init void prom_init_mem(void)
if (!memcmp(prom_init, prom_init + mem, 32))
break;
}
+ lowmem = mem;
/* Ignoring the last page when ddr size is 128M. Cached
* accesses to last page is causing the processor to prefetch
@@ -95,7 +98,6 @@ static __init void prom_init_mem(void)
*/
if (c->cputype == CPU_74K && (mem == (128 << 20)))
mem -= 0x1000;
-
add_memory_region(0, mem, BOOT_MEM_RAM);
}
@@ -114,3 +116,67 @@ void __init prom_init(void)
void __init prom_free_prom_memory(void)
{
}
+
+#if defined(CONFIG_BCM47XX_BCMA) && defined(CONFIG_HIGHMEM)
+
+#define EXTVBASE 0xc0000000
+#define ENTRYLO(x) ((pte_val(pfn_pte((x) >> _PFN_SHIFT, PAGE_KERNEL_UNCACHED)) >> 6) | 1)
+
+#include <asm/tlbflush.h>
+
+/* Stripped version of tlb_init, with the call to build_tlb_refill_handler
+ * dropped. Calling it at this stage causes a hang.
+ */
+void __cpuinit early_tlb_init(void)
+{
+ write_c0_pagemask(PM_DEFAULT_MASK);
+ write_c0_wired(0);
+ temp_tlb_entry = current_cpu_data.tlbsize - 1;
+ local_flush_tlb_all();
+}
+
+void __init bcm47xx_prom_highmem_init(void)
+{
+ unsigned long off = (unsigned long)prom_init;
+ unsigned long extmem = 0;
+ bool highmem_region = false;
+
+ if (WARN_ON(bcm47xx_bus_type != BCM47XX_BUS_TYPE_BCMA))
+ return;
+
+ if (bcm47xx_bus.bcma.bus.chipinfo.id == BCMA_CHIP_ID_BCM4706)
+ highmem_region = true;
+
+ if (lowmem != 128 << 20 || !highmem_region)
+ return;
+
+ early_tlb_init();
+
+ /* Add one temporary TLB entry to map SDRAM Region 2.
+ * Physical Virtual
+ * 0x80000000 0xc0000000 (1st: 256MB)
+ * 0x90000000 0xd0000000 (2nd: 256MB)
+ */
+ add_temporary_entry(ENTRYLO(0x80000000),
+ ENTRYLO(0x80000000 + (256 << 20)),
+ EXTVBASE, PM_256M);
+
+ off = EXTVBASE + __pa(off);
+ for (extmem = 128 << 20; extmem < 512 << 20; extmem <<= 1) {
+ if (!memcmp(prom_init, (void *)(off + extmem), 16))
+ break;
+ }
+ extmem -= lowmem;
+
+ early_tlb_init();
+
+ if (!extmem)
+ return;
+
+ pr_warn("Found %lu MiB of extra memory, but highmem is unsupported yet!\n",
+ extmem >> 20);
+
+ /* TODO: Register extra memory */
+}
+
+#endif /* defined(CONFIG_BCM47XX_BCMA) && defined(CONFIG_HIGHMEM) */