RISC-V: Add early ioremap support

UEFI uses early IO or memory mappings for runtime services before
normal ioremap() is usable. Add the necessary fixmap bindings and
pmd mappings for generic ioremap support to work.

Signed-off-by: Atish Patra <atish.patra@wdc.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index df18372861d8d22e3c0f6b8485c6128c65de733b..5e4ace64acbc10936d2b87aa0f96bd26b0bf460a 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -37,6 +37,7 @@ config RISCV
        select GENERIC_ARCH_TOPOLOGY if SMP
        select GENERIC_ATOMIC64 if !64BIT
        select GENERIC_CLOCKEVENTS
+       select GENERIC_EARLY_IOREMAP
        select GENERIC_GETTIMEOFDAY if HAVE_GENERIC_VDSO
        select GENERIC_IOREMAP
        select GENERIC_IRQ_MULTI_HANDLER

diff --git a/arch/riscv/include/asm/Kbuild b/arch/riscv/include/asm/Kbuild
index 3d9410bb4de02fed190dd9214c9dd4cf2ecdaa85..59dd7be550054fb785029616074579ab32dd8835 100644 (file)
--- a/arch/riscv/include/asm/Kbuild
+++ b/arch/riscv/include/asm/Kbuild
@@ -1,4 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0
+generic-y += early_ioremap.h
 generic-y += extable.h
 generic-y += flat.h
 generic-y += kvm_para.h

diff --git a/arch/riscv/include/asm/fixmap.h b/arch/riscv/include/asm/fixmap.h
index 11613f38228ae7804e01e83c985353db3b526141..54cbf07fb4e9647a73d63cdc3c15595dc01e6b94 100644 (file)
--- a/arch/riscv/include/asm/fixmap.h
+++ b/arch/riscv/include/asm/fixmap.h
@@ -27,6 +27,19 @@ enum fixed_addresses {
        FIX_TEXT_POKE1,
        FIX_TEXT_POKE0,
        FIX_EARLYCON_MEM_BASE,
+
+       __end_of_permanent_fixed_addresses,
+       /*
+        * Temporary boot-time mappings, used by early_ioremap(),
+        * before ioremap() is functional.
+        */
+#define NR_FIX_BTMAPS          (SZ_256K / PAGE_SIZE)
+#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_fixed_addresses
 };
 

diff --git a/arch/riscv/include/asm/io.h b/arch/riscv/include/asm/io.h
index 3835c3295dc51bbc90e7a9a21bcde1a148f1019e..c025a746a1486c1af7e3e860b355429610eeeb56 100644 (file)
--- a/arch/riscv/include/asm/io.h
+++ b/arch/riscv/include/asm/io.h
@@ -14,6 +14,7 @@
 #include <linux/types.h>
 #include <linux/pgtable.h>
 #include <asm/mmiowb.h>
+#include <asm/early_ioremap.h>
 
 /*
  * MMIO access functions are separated out to break dependency cycles

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index edea7ef884021fd2d2fa954d41539da4e7d70806..41ef96d0d97a62ac6026275486bde106e565a2cf 100644 (file)
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -19,6 +19,7 @@
 #include <linux/smp.h>
 
 #include <asm/cpu_ops.h>
+#include <asm/early_ioremap.h>
 #include <asm/setup.h>
 #include <asm/sections.h>
 #include <asm/sbi.h>
@@ -71,6 +72,7 @@ void __init setup_arch(char **cmdline_p)
 
        *cmdline_p = boot_command_line;
 
+       early_ioremap_setup();
        parse_early_param();
 
        setup_bootmem();

diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
index 2b651f63f5c4b6522046fe8f8ef0452876e92998..b75ebe8e7a92d3efa917d91d414e37b882992ea7 100644 (file)
--- a/arch/riscv/mm/init.c
+++ b/arch/riscv/mm/init.c
@@ -403,6 +403,9 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
        uintptr_t load_pa = (uintptr_t)(&_start);
        uintptr_t load_sz = (uintptr_t)(&_end) - load_pa;
        uintptr_t map_size = best_map_size(load_pa, MAX_EARLY_MAPPING_SIZE);
+#ifndef __PAGETABLE_PMD_FOLDED
+       pmd_t fix_bmap_spmd, fix_bmap_epmd;
+#endif
 
        va_pa_offset = PAGE_OFFSET - load_pa;
        pfn_base = PFN_DOWN(load_pa);
@@ -456,6 +459,36 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa)
                           pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL);
        dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1));
        dtb_early_pa = dtb_pa;
+
+       /*
+        * Bootime fixmap only can handle PMD_SIZE mapping. Thus, boot-ioremap
+        * range can not span multiple pmds.
+        */
+       BUILD_BUG_ON((__fix_to_virt(FIX_BTMAP_BEGIN) >> PMD_SHIFT)
+                    != (__fix_to_virt(FIX_BTMAP_END) >> PMD_SHIFT));
+
+#ifndef __PAGETABLE_PMD_FOLDED
+       /*
+        * Early ioremap fixmap is already created as it lies within first 2MB
+        * of fixmap region. We always map PMD_SIZE. Thus, both FIX_BTMAP_END
+        * FIX_BTMAP_BEGIN should lie in the same pmd. Verify that and warn
+        * the user if not.
+        */
+       fix_bmap_spmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_BEGIN))];
+       fix_bmap_epmd = fixmap_pmd[pmd_index(__fix_to_virt(FIX_BTMAP_END))];
+       if (pmd_val(fix_bmap_spmd) != pmd_val(fix_bmap_epmd)) {
+               WARN_ON(1);
+               pr_warn("fixmap btmap start [%08lx] != end [%08lx]\n",
+                       pmd_val(fix_bmap_spmd), pmd_val(fix_bmap_epmd));
+               pr_warn("fix_to_virt(FIX_BTMAP_BEGIN): %08lx\n",
+                       fix_to_virt(FIX_BTMAP_BEGIN));
+               pr_warn("fix_to_virt(FIX_BTMAP_END):   %08lx\n",
+                       fix_to_virt(FIX_BTMAP_END));
+
+               pr_warn("FIX_BTMAP_END:       %d\n", FIX_BTMAP_END);
+               pr_warn("FIX_BTMAP_BEGIN:     %d\n", FIX_BTMAP_BEGIN);
+       }
+#endif
 }
 
 static void __init setup_vm_final(void)