ARM: OMAP: Cleanup OMAP FB SDRAM reservation
The logic in this file is rather convoluted, but essentially:
1. region type 0 is SDRAM
2. referring to the code fragment
if (set_fbmem_region_type(&rg, OMAPFB_MEMTYPE_SDRAM,
sdram_start, sdram_size) < 0 ||
(rg.type != OMAPFB_MEMTYPE_SDRAM))
continue;
- if rg.type is not OMAPFB_MEMTYPE_SDRAM, set_fbmem_region_type()
returns zero immediately (since rg.type is non-zero), and so we
'continue'.
- if rg.type is OMAPFB_MEMTYPE_SDRAM, and rg.paddr is zero,
we fall through.
- if rg.type is OMAPFB_MEMTYPE_SDRAM, and the region lies within
SDRAM, we fall through.
- if rg.type is OMAPFB_MEMTYPE_SDRAM, and the region is not within
SDRAM, we 'continue'.
3. check_fbmem_region seems unnecessary.
- we know rg.type is OMAPFB_MEMTYPE_SDRAM
- we can check rg.size independently
- bootmem_reserve() can check for overlapping reservations itself
- we've already validated that the requested region lies within SDRAM.
4. avoid BUG()ing if the region entry is already set; print an error,
and mark the configuration invalid - at least we'll continue booting
so the error message has a chance of being logged/visible via serial
console.
With these changes in place, it makes the code much easier to understand
and hence easier to convert to LMB.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/plat-omap/fb.c b/arch/arm/plat-omap/fb.c
index d3eea4f..97db493 100644
--- a/arch/arm/plat-omap/fb.c
+++ b/arch/arm/plat-omap/fb.c
@@ -171,49 +171,76 @@
return 0;
}
+static int valid_sdram(unsigned long addr, unsigned long size)
+{
+ struct bootmem_data *bdata = NODE_DATA(0)->bdata;
+ unsigned long sdram_start, sdram_end;
+
+ sdram_start = bdata->node_min_pfn << PAGE_SHIFT;
+ sdram_end = bdata->node_low_pfn << PAGE_SHIFT;
+
+ return addr >= sdram_start && sdram_end - addr >= size;
+}
+
+static int reserve_sdram(unsigned long addr, unsigned long size)
+{
+ return reserve_bootmem(addr, size, BOOTMEM_EXCLUSIVE);
+}
+
/*
* Called from map_io. We need to call to this early enough so that we
* can reserve the fixed SDRAM regions before VM could get hold of them.
*/
void __init omapfb_reserve_sdram(void)
{
- struct bootmem_data *bdata;
- unsigned long sdram_start, sdram_size;
- unsigned long reserved;
- int i;
+ unsigned long reserved = 0;
+ int i;
if (config_invalid)
return;
- bdata = NODE_DATA(0)->bdata;
- sdram_start = bdata->node_min_pfn << PAGE_SHIFT;
- sdram_size = (bdata->node_low_pfn << PAGE_SHIFT) - sdram_start;
- reserved = 0;
for (i = 0; ; i++) {
- struct omapfb_mem_region rg;
+ struct omapfb_mem_region rg;
if (get_fbmem_region(i, &rg) < 0)
break;
+
if (i == OMAPFB_PLANE_NUM) {
- printk(KERN_ERR
- "Extraneous FB mem configuration entries\n");
+ pr_err("Extraneous FB mem configuration entries\n");
config_invalid = 1;
return;
}
+
/* Check if it's our memory type. */
- if (set_fbmem_region_type(&rg, OMAPFB_MEMTYPE_SDRAM,
- sdram_start, sdram_size) < 0 ||
- (rg.type != OMAPFB_MEMTYPE_SDRAM))
+ if (rg.type != OMAPFB_MEMTYPE_SDRAM)
continue;
- BUG_ON(omapfb_config.mem_desc.region[i].size);
- if (check_fbmem_region(i, &rg, sdram_start, sdram_size) < 0) {
+
+ /* Check if the region falls within SDRAM */
+ if (rg.paddr && !valid_sdram(rg.paddr, rg.size))
+ continue;
+
+ if (rg.size == 0) {
+ pr_err("Zero size for FB region %d\n", i);
config_invalid = 1;
return;
}
+
if (rg.paddr) {
- reserve_bootmem(rg.paddr, rg.size, BOOTMEM_DEFAULT);
+ if (reserve_sdram(rg.paddr, rg.size)) {
+ pr_err("Trying to use reserved memory for FB region %d\n",
+ i);
+ config_invalid = 1;
+ return;
+ }
reserved += rg.size;
}
+
+ if (omapfb_config.mem_desc.region[i].size) {
+ pr_err("FB region %d already set\n", i);
+ config_invalid = 1;
+ return;
+ }
+
omapfb_config.mem_desc.region[i] = rg;
configured_regions++;
}