ARM: add support for generic early_ioremap/early_memremap

This enables the generic early_ioremap implementation for ARM.

It uses the fixmap region reserved for kmap. Since early_ioremap
is only supported before paging_init(), and kmap is only supported
afterwards, this is guaranteed not to cause any clashes.

Tested-by: Ryan Harkin <ryan.harkin@linaro.org>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>

diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index 34e1569a11ee322a0a020bdfe0c9b801b6b58c12..446e49b56e6ae26a958e7c4214676df4c1664200 100644 (file)
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -20,6 +20,7 @@ config ARM
        select GENERIC_ALLOCATOR
        select GENERIC_ATOMIC64 if (CPU_V7M || CPU_V6 || !CPU_32v6K || !AEABI)
        select GENERIC_CLOCKEVENTS_BROADCAST if SMP
+       select GENERIC_EARLY_IOREMAP
        select GENERIC_IDLE_POLL_SETUP
        select GENERIC_IRQ_PROBE
        select GENERIC_IRQ_SHOW

diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
index bd425302c97a3ec9966d4c04bdb61c3c40252056..16da6380eb8505a9f9b87db77ac4b56c1febd8d9 100644 (file)
--- a/arch/arm/include/asm/Kbuild
+++ b/arch/arm/include/asm/Kbuild
@@ -3,6 +3,7 @@
 generic-y += bitsperlong.h
 generic-y += cputime.h
 generic-y += current.h
+generic-y += early_ioremap.h
 generic-y += emergency-restart.h
 generic-y += errno.h
 generic-y += exec.h

diff --git a/arch/arm/include/asm/fixmap.h b/arch/arm/include/asm/fixmap.h
index 58cfe9f1a687e6e1c8794f5ff5f37c6b4fcd7cb9..5c17d2dec777f627eaf6b706f92053065d5fa06b 100644 (file)
--- a/arch/arm/include/asm/fixmap.h
+++ b/arch/arm/include/asm/fixmap.h
@@ -19,20 +19,47 @@ enum fixed_addresses {
        FIX_TEXT_POKE0,
        FIX_TEXT_POKE1,
 
-       __end_of_fixed_addresses
+       __end_of_fixmap_region,
+
+       /*
+        * Share the kmap() region with early_ioremap(): this is guaranteed
+        * not to clash since early_ioremap() is only available before
+        * paging_init(), and kmap() only after.
+        */
+#define NR_FIX_BTMAPS          32
+#define FIX_BTMAPS_SLOTS       7
+#define TOTAL_FIX_BTMAPS       (NR_FIX_BTMAPS * FIX_BTMAPS_SLOTS)
+
+       FIX_BTMAP_END = __end_of_permanent_fixed_addresses,
+       FIX_BTMAP_BEGIN = FIX_BTMAP_END + TOTAL_FIX_BTMAPS - 1,
+       __end_of_early_ioremap_region
 };
 
+static const enum fixed_addresses __end_of_fixed_addresses =
+       __end_of_fixmap_region > __end_of_early_ioremap_region ?
+       __end_of_fixmap_region : __end_of_early_ioremap_region;
+
 #define FIXMAP_PAGE_COMMON     (L_PTE_YOUNG | L_PTE_PRESENT | L_PTE_XN | L_PTE_DIRTY)
 
 #define FIXMAP_PAGE_NORMAL     (FIXMAP_PAGE_COMMON | L_PTE_MT_WRITEBACK)
+#define FIXMAP_PAGE_RO         (FIXMAP_PAGE_NORMAL | L_PTE_RDONLY)
 
 /* Used by set_fixmap_(io|nocache), both meant for mapping a device */
 #define FIXMAP_PAGE_IO         (FIXMAP_PAGE_COMMON | L_PTE_MT_DEV_SHARED | L_PTE_SHARED)
 #define FIXMAP_PAGE_NOCACHE    FIXMAP_PAGE_IO
 
+#define __early_set_fixmap     __set_fixmap
+
+#ifdef CONFIG_MMU
+
 void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
 void __init early_fixmap_init(void);
 
 #include <asm-generic/fixmap.h>
 
+#else
+
+static inline void early_fixmap_init(void) { }
+
+#endif
 #endif

diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 20edd349d379f22c583438db7fbf52f46e1133ef..5df2bca57c4201c3e2548ef438c980b968fb5784 100644 (file)
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -38,6 +38,7 @@
 #include <asm/cpu.h>
 #include <asm/cputype.h>
 #include <asm/elf.h>
+#include <asm/early_ioremap.h>
 #include <asm/fixmap.h>
 #include <asm/procinfo.h>
 #include <asm/psci.h>
@@ -956,8 +957,8 @@ void __init setup_arch(char **cmdline_p)
        strlcpy(cmd_line, boot_command_line, COMMAND_LINE_SIZE);
        *cmdline_p = cmd_line;
 
-       if (IS_ENABLED(CONFIG_FIX_EARLYCON_MEM))
-               early_fixmap_init();
+       early_fixmap_init();
+       early_ioremap_init();
 
        parse_early_param();
 
@@ -968,6 +969,8 @@ void __init setup_arch(char **cmdline_p)
        sanity_check_meminfo();
        arm_memblock_init(mdesc);
 
+       early_ioremap_reset();
+
        paging_init(mdesc);
        request_standard_resources(mdesc);
 

diff --git a/arch/arm/mm/ioremap.c b/arch/arm/mm/ioremap.c
index 0c81056c1dd7edac30e1d86bdd2103d1e2d6832f..66a978d059585f671d1d68277a200b661ef9637b 100644 (file)
--- a/arch/arm/mm/ioremap.c
+++ b/arch/arm/mm/ioremap.c
@@ -30,6 +30,7 @@
 #include <asm/cp15.h>
 #include <asm/cputype.h>
 #include <asm/cacheflush.h>
+#include <asm/early_ioremap.h>
 #include <asm/mmu_context.h>
 #include <asm/pgalloc.h>
 #include <asm/tlbflush.h>
@@ -469,3 +470,11 @@ int pci_ioremap_io(unsigned int offset, phys_addr_t phys_addr)
 }
 EXPORT_SYMBOL_GPL(pci_ioremap_io);
 #endif
+
+/*
+ * Must be called after early_fixmap_init
+ */
+void __init early_ioremap_init(void)
+{
+       early_ioremap_setup();
+}

diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index 4867f5daf82c99bdf4ee64ebb6b61613cd792a3e..de19f90221e2f313b763a90649d52db42c970147 100644 (file)
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -390,7 +390,7 @@ void __init early_fixmap_init(void)
         * The early fixmap range spans multiple pmds, for which
         * we are not prepared:
         */
-       BUILD_BUG_ON((__fix_to_virt(__end_of_permanent_fixed_addresses) >> PMD_SHIFT)
+       BUILD_BUG_ON((__fix_to_virt(__end_of_early_ioremap_region) >> PMD_SHIFT)
                     != FIXADDR_TOP >> PMD_SHIFT);
 
        pmd = fixmap_pmd(FIXADDR_TOP);