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SubjectRe: [PATCH v3 4/6] arm: add early_ioremap support
On 1/9/2014 7:50 PM, Mark Salter wrote:
....
> diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
> index 987a7f5..038fb75 100644
> --- a/arch/arm/kernel/setup.c
> +++ b/arch/arm/kernel/setup.c
> @@ -36,6 +36,7 @@
> #include <asm/cpu.h>
> #include <asm/cputype.h>
> #include <asm/elf.h>
> +#include <asm/io.h>
> #include <asm/procinfo.h>
> #include <asm/psci.h>
> #include <asm/sections.h>
> @@ -887,6 +888,8 @@ void __init setup_arch(char **cmdline_p)
>
> parse_early_param();
>
> + early_ioremap_init();
> +
> sort(&meminfo.bank, meminfo.nr_banks, sizeof(meminfo.bank[0]), meminfo_cmp, NULL);
>
> early_paging_init(mdesc, lookup_processor_type(read_cpuid_id()));

Any chance we could do this even earlier, say right after
setup_processor? It would be nice to be able to do this while FDT
scanning (I have a use case in mind, potential patches are in the works)

<snip>
> diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
> index 580ef2d..bef59b9 100644
> --- a/arch/arm/mm/mmu.c
> +++ b/arch/arm/mm/mmu.c
> @@ -34,6 +34,7 @@
> #include <asm/mach/arch.h>
> #include <asm/mach/map.h>
> #include <asm/mach/pci.h>
> +#include <asm/early_ioremap.h>
>
> #include "mm.h"
> #include "tcm.h"
> @@ -1405,6 +1406,7 @@ void __init paging_init(const struct machine_desc *mdesc)
> {
> void *zero_page;
>
> + early_ioremap_reset();
> build_mem_type_table();
> prepare_page_table();
> map_lowmem();
>

Neither x86 nor arm64 get rid of existing mapping in paging_init. Is
there a reason this needs to be here for arm? Are there concerns about
alias mappings?

Thanks,
Laura

--
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