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arm: Add devicetree fixup machine function 

Commit 1c2f87c225
(ARM: 8025/1: Get rid of meminfo) dropped the upper bound on
the number of memory banks that can be added as there was no
technical need in the kernel. It turns out though, some bootloaders
(specifically the arndale-octa exynos boards) may pass invalid memory
information and rely on the kernel to not parse this data. This is a
bug in the bootloader but we still need to work around this.
Work around this by introducing a dt_fixup function. This function
gets called before the flattened devicetree is scanned for memory
and the like. In this fixup function for exynos, limit the maximum
number of memory regions in the devicetree.

Signed-off-by: Laura Abbott <lauraa@codeaurora.org>
Tested-by: Andreas Färber <afaerber@suse.de>
[glikely: Added a comment and fixed up function name]
Signed-off-by: Grant Likely <grant.likely@linaro.org>
This commit is contained in:
Laura Abbott 2014-07-15 10:03:36 -07:00 committed by Grant Likely
parent 704033cee2
commit 5a12a597a8
3 changed files with 18 additions and 1 deletions
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1
arch/arm/include/asm/mach/arch.h
View File

@ -50,6 +50,7 @@ struct machine_desc {
struct smp_operations *smp; /* SMP operations */
bool (*smp_init)(void);
void (*fixup)(struct tag *, char **);
void (*dt_fixup)(void);
void (*init_meminfo)(void);
void (*reserve)(void);/* reserve mem blocks */
void (*map_io)(void);/* IO mapping function */

8
arch/arm/kernel/devtree.c
View File

@ -212,7 +212,7 @@ const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
mdesc_best = &__mach_desc_GENERIC_DT;
#endif
if (!dt_phys || !early_init_dt_scan(phys_to_virt(dt_phys)))
if (!dt_phys || !early_init_dt_verify(phys_to_virt(dt_phys)))
return NULL;
mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);
@ -237,6 +237,12 @@ const struct machine_desc * __init setup_machine_fdt(unsigned int dt_phys)
dump_machine_table(); /* does not return */
}
/* We really don't want to do this, but sometimes firmware provides buggy data */
if (mdesc->dt_fixup)
mdesc->dt_fixup();
early_init_dt_scan_nodes();
/* Change machine number to match the mdesc we're using */
__machine_arch_type = mdesc->nr;

10
arch/arm/mach-exynos/exynos.c
View File

@ -335,6 +335,15 @@ static void __init exynos_reserve(void)
#endif
}
static void __init exynos_dt_fixup(void)
{
/*
* Some versions of uboot pass garbage entries in the memory node,
* use the old CONFIG_ARM_NR_BANKS
*/
of_fdt_limit_memory(8);
}
DT_MACHINE_START(EXYNOS_DT, "SAMSUNG EXYNOS (Flattened Device Tree)")
/* Maintainer: Thomas Abraham <thomas.abraham@linaro.org> */
/* Maintainer: Kukjin Kim <kgene.kim@samsung.com> */
@ -348,4 +357,5 @@ DT_MACHINE_START(EXYNOS_DT, "SAMSUNG EXYNOS (Flattened Device Tree)")
.dt_compat = exynos_dt_compat,
.restart = exynos_restart,
.reserve = exynos_reserve,
.dt_fixup = exynos_dt_fixup,
MACHINE_END