Re: [PATCH v17 09/10] of: fdt: Add memory for devices by DT property "linux,usable-memory-range"

Rob Herring
2021-12-10T16:43:27Z

On Fri, 10 Dec 2021 14:55:32 +0800, Zhen Lei wrote:
> From: Chen Zhou <chenzhou10@huawei.com>
>
> When reserving crashkernel in high memory, some low memory is reserved
> for crash dump kernel devices and never mapped by the first kernel.
> This memory range is advertised to crash dump kernel via DT property
> under /chosen,
> linux,usable-memory-range = <BASE1 SIZE1 [BASE2 SIZE2]>
>
> We reused the DT property linux,usable-memory-range and made the low
> memory region as the second range "BASE2 SIZE2", which keeps compatibility
> with existing user-space and older kdump kernels.
>
> Crash dump kernel reads this property at boot time and call memblock_add()
> to add the low memory region after memblock_cap_memory_range() has been
> called.
>
> Signed-off-by: Chen Zhou <chenzhou10@huawei.com>
> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
> Tested-by: Dave Kleikamp <dave.kleikamp@oracle.com>
> ---
> drivers/of/fdt.c | 33 +++++++++++++++++++++++----------
> 1 file changed, 23 insertions(+), 10 deletions(-)
>

Reviewed-by: Rob Herring <robh@kernel.org>