diff options
Diffstat (limited to 'arch/arm64')
| -rw-r--r-- | arch/arm64/Kconfig.debug | 9 | ||||
| -rw-r--r-- | arch/arm64/include/asm/io.h | 3 | ||||
| -rw-r--r-- | arch/arm64/include/asm/memory.h | 1 | ||||
| -rw-r--r-- | arch/arm64/include/asm/mmu.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kernel/Makefile | 1 | ||||
| -rw-r--r-- | arch/arm64/kernel/early_printk.c | 118 | ||||
| -rw-r--r-- | arch/arm64/kernel/head.S | 12 | ||||
| -rw-r--r-- | arch/arm64/mm/mmu.c | 42 |
8 files changed, 185 insertions, 2 deletions
diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug index d7553f2bda6..79871cd78da 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -24,4 +24,13 @@ config DEBUG_STACK_USAGE Enables the display of the minimum amount of free stack which each task has ever had available in the sysrq-T output. +config EARLY_PRINTK + bool "Early printk support" + default y + help + Say Y here if you want to have an early console using the + earlyprintk=<name>[,<addr>][,<options>] kernel parameter. It + is assumed that the early console device has been initialised + by the boot loader prior to starting the Linux kernel. + endmenu diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h index d2f05a60827..57f12c991de 100644 --- a/arch/arm64/include/asm/io.h +++ b/arch/arm64/include/asm/io.h @@ -230,6 +230,9 @@ extern void __iounmap(volatile void __iomem *addr); #define ioremap_wc(addr, size) __ioremap((addr), (size), __pgprot(PROT_NORMAL_NC)) #define iounmap __iounmap +#define PROT_SECT_DEFAULT (PMD_TYPE_SECT | PMD_SECT_AF) +#define PROT_SECT_DEVICE_nGnRE (PROT_SECT_DEFAULT | PTE_PXN | PTE_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE)) + #define ARCH_HAS_IOREMAP_WC #include <asm-generic/iomap.h> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h index 1cac16a001c..381f556b664 100644 --- a/arch/arm64/include/asm/memory.h +++ b/arch/arm64/include/asm/memory.h @@ -43,6 +43,7 @@ #define PAGE_OFFSET UL(0xffffffc000000000) #define MODULES_END (PAGE_OFFSET) #define MODULES_VADDR (MODULES_END - SZ_64M) +#define EARLYCON_IOBASE (MODULES_VADDR - SZ_4M) #define VA_BITS (39) #define TASK_SIZE_64 (UL(1) << VA_BITS) diff --git a/arch/arm64/include/asm/mmu.h b/arch/arm64/include/asm/mmu.h index d4f7fd5b9e3..2494fc01896 100644 --- a/arch/arm64/include/asm/mmu.h +++ b/arch/arm64/include/asm/mmu.h @@ -26,5 +26,6 @@ typedef struct { extern void paging_init(void); extern void setup_mm_for_reboot(void); +extern void __iomem *early_io_map(phys_addr_t phys, unsigned long virt); #endif diff --git a/arch/arm64/kernel/Makefile b/arch/arm64/kernel/Makefile index 74239c31e25..a1cace45e97 100644 --- a/arch/arm64/kernel/Makefile +++ b/arch/arm64/kernel/Makefile @@ -17,6 +17,7 @@ arm64-obj-$(CONFIG_MODULES) += arm64ksyms.o module.o arm64-obj-$(CONFIG_SMP) += smp.o arm64-obj-$(CONFIG_HW_PERF_EVENTS) += perf_event.o arm64-obj-$(CONFIG_HAVE_HW_BREAKPOINT)+= hw_breakpoint.o +arm64-obj-$(CONFIG_EARLY_PRINTK) += early_printk.o obj-y += $(arm64-obj-y) vdso/ obj-m += $(arm64-obj-m) diff --git a/arch/arm64/kernel/early_printk.c b/arch/arm64/kernel/early_printk.c new file mode 100644 index 00000000000..7e320a2edb9 --- /dev/null +++ b/arch/arm64/kernel/early_printk.c @@ -0,0 +1,118 @@ +/* + * Earlyprintk support. + * + * Copyright (C) 2012 ARM Ltd. + * Author: Catalin Marinas <catalin.marinas@arm.com> + * + * This program is free software: you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#include <linux/kernel.h> +#include <linux/console.h> +#include <linux/init.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/io.h> + +#include <linux/amba/serial.h> + +static void __iomem *early_base; +static void (*printch)(char ch); + +/* + * PL011 single character TX. + */ +static void pl011_printch(char ch) +{ + while (readl_relaxed(early_base + UART01x_FR) & UART01x_FR_TXFF) + ; + writeb_relaxed(ch, early_base + UART01x_DR); + while (readl_relaxed(early_base + UART01x_FR) & UART01x_FR_BUSY) + ; +} + +struct earlycon_match { + const char *name; + void (*printch)(char ch); +}; + +static const struct earlycon_match earlycon_match[] __initconst = { + { .name = "pl011", .printch = pl011_printch, }, + {} +}; + +static void early_write(struct console *con, const char *s, unsigned n) +{ + while (n-- > 0) { + if (*s == '\n') + printch('\r'); + printch(*s); + s++; + } +} + +static struct console early_console = { + .name = "earlycon", + .write = early_write, + .flags = CON_PRINTBUFFER | CON_BOOT, + .index = -1, +}; + +/* + * Parse earlyprintk=... parameter in the format: + * + * <name>[,<addr>][,<options>] + * + * and register the early console. It is assumed that the UART has been + * initialised by the bootloader already. + */ +static int __init setup_early_printk(char *buf) +{ + const struct earlycon_match *match = earlycon_match; + phys_addr_t paddr = 0; + + if (!buf) { + pr_warning("No earlyprintk arguments passed.\n"); + return 0; + } + + while (match->name) { + size_t len = strlen(match->name); + if (!strncmp(buf, match->name, len)) { + buf += len; + break; + } + match++; + } + if (!match->name) { + pr_warning("Unknown earlyprintk arguments: %s\n", buf); + return 0; + } + + /* I/O address */ + if (!strncmp(buf, ",0x", 3)) { + char *e; + paddr = simple_strtoul(buf + 1, &e, 16); + buf = e; + } + /* no options parsing yet */ + + if (paddr) + early_base = early_io_map(paddr, EARLYCON_IOBASE); + + printch = match->printch; + register_console(&early_console); + + return 0; +} + +early_param("earlyprintk", setup_early_printk); diff --git a/arch/arm64/kernel/head.S b/arch/arm64/kernel/head.S index 368ad1f7c36..0a0a4975682 100644 --- a/arch/arm64/kernel/head.S +++ b/arch/arm64/kernel/head.S @@ -82,10 +82,8 @@ #ifdef CONFIG_ARM64_64K_PAGES #define MM_MMUFLAGS PTE_ATTRINDX(MT_NORMAL) | PTE_FLAGS -#define IO_MMUFLAGS PTE_ATTRINDX(MT_DEVICE_nGnRE) | PTE_XN | PTE_FLAGS #else #define MM_MMUFLAGS PMD_ATTRINDX(MT_NORMAL) | PMD_FLAGS -#define IO_MMUFLAGS PMD_ATTRINDX(MT_DEVICE_nGnRE) | PMD_SECT_XN | PMD_FLAGS #endif /* @@ -368,6 +366,7 @@ ENDPROC(__calc_phys_offset) * - identity mapping to enable the MMU (low address, TTBR0) * - first few MB of the kernel linear mapping to jump to once the MMU has * been enabled, including the FDT blob (TTBR1) + * - UART mapping if CONFIG_EARLY_PRINTK is enabled (TTBR1) */ __create_page_tables: pgtbl x25, x26, x24 // idmap_pg_dir and swapper_pg_dir addresses @@ -420,6 +419,15 @@ __create_page_tables: sub x6, x6, #1 // inclusive range create_block_map x0, x7, x3, x5, x6 1: +#ifdef CONFIG_EARLY_PRINTK + /* + * Create the pgd entry for the UART mapping. The full mapping is done + * later based earlyprintk kernel parameter. + */ + ldr x5, =EARLYCON_IOBASE // UART virtual address + add x0, x26, #2 * PAGE_SIZE // section table address + create_pgd_entry x26, x0, x5, x6, x7 +#endif ret ENDPROC(__create_page_tables) .ltorg diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c index a6885d896ab..f4dd585898c 100644 --- a/arch/arm64/mm/mmu.c +++ b/arch/arm64/mm/mmu.c @@ -25,6 +25,7 @@ #include <linux/nodemask.h> #include <linux/memblock.h> #include <linux/fs.h> +#include <linux/io.h> #include <asm/cputype.h> #include <asm/sections.h> @@ -251,6 +252,47 @@ static void __init create_mapping(phys_addr_t phys, unsigned long virt, } while (pgd++, addr = next, addr != end); } +#ifdef CONFIG_EARLY_PRINTK +/* + * Create an early I/O mapping using the pgd/pmd entries already populated + * in head.S as this function is called too early to allocated any memory. The + * mapping size is 2MB with 4KB pages or 64KB or 64KB pages. + */ +void __iomem * __init early_io_map(phys_addr_t phys, unsigned long virt) +{ + unsigned long size, mask; + bool page64k = IS_ENABLED(ARM64_64K_PAGES); + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + /* + * No early pte entries with !ARM64_64K_PAGES configuration, so using + * sections (pmd). + */ + size = page64k ? PAGE_SIZE : SECTION_SIZE; + mask = ~(size - 1); + + pgd = pgd_offset_k(virt); + pud = pud_offset(pgd, virt); + if (pud_none(*pud)) + return NULL; + pmd = pmd_offset(pud, virt); + + if (page64k) { + if (pmd_none(*pmd)) + return NULL; + pte = pte_offset_kernel(pmd, virt); + set_pte(pte, __pte((phys & mask) | PROT_DEVICE_nGnRE)); + } else { + set_pmd(pmd, __pmd((phys & mask) | PROT_SECT_DEVICE_nGnRE)); + } + + return (void __iomem *)((virt & mask) + (phys & ~mask)); +} +#endif + static void __init map_mem(void) { struct memblock_region *reg; |