[PATCH v7 07/37] nds32: Kernel booting and initialization
From: Greentime Hu
Date: Tue Feb 13 2018 - 05:03:31 EST
This patch includes the kernel startup code. It can get dtb pointer
passed from bootloader. It will create a temp mapping by tlb
instructions at beginning and goto start_kernel.
Signed-off-by: Vincent Chen <vincentc@xxxxxxxxxxxxx>
Signed-off-by: Greentime Hu <greentime@xxxxxxxxxxxxx>
---
arch/nds32/kernel/head.S | 188 ++++++++++++++++++++++++
arch/nds32/kernel/setup.c | 363 ++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 551 insertions(+)
create mode 100644 arch/nds32/kernel/head.S
create mode 100644 arch/nds32/kernel/setup.c
diff --git a/arch/nds32/kernel/head.S b/arch/nds32/kernel/head.S
new file mode 100644
index 000000000000..71f57bd70f3b
--- /dev/null
+++ b/arch/nds32/kernel/head.S
@@ -0,0 +1,188 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/ptrace.h>
+#include <asm/asm-offsets.h>
+#include <asm/page.h>
+#include <asm/pgtable.h>
+#include <asm/sizes.h>
+#include <asm/thread_info.h>
+
+#ifdef CONFIG_CPU_BIG_ENDIAN
+#define OF_DT_MAGIC 0xd00dfeed
+#else
+#define OF_DT_MAGIC 0xedfe0dd0
+#endif
+
+ .globl swapper_pg_dir
+ .equ swapper_pg_dir, TEXTADDR - 0x4000
+
+/*
+ * Kernel startup entry point.
+ */
+ .section ".head.text", "ax"
+ .type _stext, %function
+ENTRY(_stext)
+ setgie.d ! Disable interrupt
+ isb
+/*
+ * Disable I/D-cache and enable it at a proper time
+ */
+ mfsr $r0, $mr8
+ li $r1, #~(CACHE_CTL_mskIC_EN|CACHE_CTL_mskDC_EN)
+ and $r0, $r0, $r1
+ mtsr $r0, $mr8
+
+/*
+ * Process device tree blob
+ */
+ andi $r0,$r2,#0x3
+ li $r10, 0
+ bne $r0, $r10, _nodtb
+ lwi $r0, [$r2]
+ li $r1, OF_DT_MAGIC
+ bne $r0, $r1, _nodtb
+ move $r10, $r2
+_nodtb:
+
+/*
+ * Create a temporary mapping area for booting, before start_kernel
+ */
+ sethi $r4, hi20(swapper_pg_dir)
+ li $p0, (PAGE_OFFSET - PHYS_OFFSET)
+ sub $r4, $r4, $p0
+ tlbop FlushAll ! invalidate TLB\n"
+ isb
+ mtsr $r4, $L1_PPTB ! load page table pointer\n"
+
+/* set NTC0 cacheable/writeback, mutliple page size in use */
+ mfsr $r3, $MMU_CTL
+ li $r0, #~MMU_CTL_mskNTC0
+ and $r3, $r3, $r0
+#ifdef CONFIG_ANDES_PAGE_SIZE_4KB
+ ori $r3, $r3, #(MMU_CTL_mskMPZIU|(MMU_CTL_CACHEABLE_WB << MMU_CTL_offNTC0))
+#else
+ ori $r3, $r3, #(MMU_CTL_mskMPZIU|(MMU_CTL_CACHEABLE_WB << MMU_CTL_offNTC0)|MMU_CTL_D8KB)
+#endif
+#ifdef CONFIG_HW_SUPPORT_UNALIGNMENT_ACCESS
+ li $r0, #MMU_CTL_UNA
+ or $r3, $r3, $r0
+#endif
+ mtsr $r3, $MMU_CTL
+ isb
+
+/* set page size and size of kernel image */
+ mfsr $r0, $MMU_CFG
+ srli $r3, $r0, MMU_CFG_offfEPSZ
+ zeb $r3, $r3
+ bnez $r3, _extra_page_size_support
+#ifdef CONFIG_ANDES_PAGE_SIZE_4KB
+ li $r5, #SZ_4K ! Use 4KB page size
+#else
+ li $r5, #SZ_8K ! Use 8KB page size
+ li $r3, #1
+#endif
+ mtsr $r3, $TLB_MISC
+ b _image_size_check
+
+_extra_page_size_support: ! Use epzs pages size
+ clz $r6, $r3
+ subri $r2, $r6, #31
+ li $r3, #1
+ sll $r3, $r3, $r2
+ /* MMU_CFG.EPSZ value -> meaning */
+ mul $r5, $r3, $r3
+ slli $r5, $r5, #14
+ /* MMU_CFG.EPSZ -> TLB_MISC.ACC_PSZ */
+ addi $r3, $r2, #0x2
+ mtsr $r3, $TLB_MISC
+
+_image_size_check:
+ /* calculate the image maximum size accepted by TLB config */
+ andi $r6, $r0, MMU_CFG_mskTBW
+ andi $r0, $r0, MMU_CFG_mskTBS
+ srli $r6, $r6, MMU_CFG_offTBW
+ srli $r0, $r0, MMU_CFG_offTBS
+ /*
+ * we just map the kernel to the maximum way - 1 of tlb
+ * reserver one way for UART VA mapping
+ * it will cause page fault if UART mapping cover the kernel mapping
+ *
+ * direct mapping is not supported now.
+ */
+ li $r2, 't'
+ beqz $r6, __error ! MMU_CFG.TBW = 0 is direct mappin
+ addi $r0, $r0, #0x2 ! MMU_CFG.TBS value -> meaning
+ sll $r0, $r6, $r0 ! entries = k-way * n-set
+ mul $r6, $r0, $r5 ! max size = entries * page size
+ /* check kernel image size */
+ la $r3, (_end - PAGE_OFFSET)
+ li $r2, 's'
+ bgt $r3, $r6, __error
+
+ li $r2, #(PHYS_OFFSET + TLB_DATA_kernel_text_attr)
+ li $r3, PAGE_OFFSET
+ add $r6, $r6, $r3
+
+_tlb:
+ mtsr $r3, $TLB_VPN
+ dsb
+ tlbop $r2, RWR
+ isb
+ add $r3, $r3, $r5
+ add $r2, $r2, $r5
+ bgt $r6, $r3, _tlb
+ mfsr $r3, $TLB_MISC ! setup access page size
+ li $r2, #~0xf
+ and $r3, $r3, $r2
+#ifdef CONFIG_ANDES_PAGE_SIZE_8KB
+ ori $r3, $r3, #0x1
+#endif
+ mtsr $r3, $TLB_MISC
+
+ mfsr $r0, $MISC_CTL ! Enable BTB and RTP and shadow sp
+ ori $r0, $r0, #MISC_init
+ mtsr $r0, $MISC_CTL
+
+ mfsr $p1, $PSW
+ li $r15, #~PSW_clr ! clear WBNA|DME|IME|DT|IT|POM|INTL|GIE
+ and $p1, $p1, $r15
+ ori $p1, $p1, #PSW_init
+ mtsr $p1, $IPSW ! when iret, it will automatically enable MMU
+ la $lp, __mmap_switched
+ mtsr $lp, $IPC
+ iret
+ nop
+
+ .type __switch_data, %object
+__switch_data:
+ .long __bss_start ! $r6
+ .long _end ! $r7
+ .long __atags_pointer ! $atag_pointer
+ .long init_task ! $r9, move to $r25
+ .long init_thread_union + THREAD_SIZE ! $sp
+
+
+/*
+ * The following fragment of code is executed with the MMU on in MMU mode,
+ * and uses absolute addresses; this is not position independent.
+ */
+ .align
+ .type __mmap_switched, %function
+__mmap_switched:
+ la $r3, __switch_data
+ lmw.bim $r6, [$r3], $r9, #0b0001
+ move $r25, $r9
+ move $fp, #0 ! Clear BSS (and zero $fp)
+ beq $r7, $r6, _RRT
+1: swi.bi $fp, [$r6], #4
+ bne $r7, $r6, 1b
+ swi $r10, [$r8]
+
+_RRT:
+ b start_kernel
+
+__error:
+ b __error
diff --git a/arch/nds32/kernel/setup.c b/arch/nds32/kernel/setup.c
new file mode 100644
index 000000000000..ba910e9e4ecb
--- /dev/null
+++ b/arch/nds32/kernel/setup.c
@@ -0,0 +1,363 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2005-2017 Andes Technology Corporation
+
+#include <linux/cpu.h>
+#include <linux/bootmem.h>
+#include <linux/seq_file.h>
+#include <linux/memblock.h>
+#include <linux/console.h>
+#include <linux/screen_info.h>
+#include <linux/delay.h>
+#include <linux/dma-mapping.h>
+#include <linux/of_fdt.h>
+#include <linux/of_platform.h>
+#include <asm/setup.h>
+#include <asm/sections.h>
+#include <asm/proc-fns.h>
+#include <asm/cache_info.h>
+#include <asm/elf.h>
+#include <nds32_intrinsic.h>
+
+#define HWCAP_MFUSR_PC 0x000001
+#define HWCAP_EXT 0x000002
+#define HWCAP_EXT2 0x000004
+#define HWCAP_FPU 0x000008
+#define HWCAP_AUDIO 0x000010
+#define HWCAP_BASE16 0x000020
+#define HWCAP_STRING 0x000040
+#define HWCAP_REDUCED_REGS 0x000080
+#define HWCAP_VIDEO 0x000100
+#define HWCAP_ENCRYPT 0x000200
+#define HWCAP_EDM 0x000400
+#define HWCAP_LMDMA 0x000800
+#define HWCAP_PFM 0x001000
+#define HWCAP_HSMP 0x002000
+#define HWCAP_TRACE 0x004000
+#define HWCAP_DIV 0x008000
+#define HWCAP_MAC 0x010000
+#define HWCAP_L2C 0x020000
+#define HWCAP_FPU_DP 0x040000
+#define HWCAP_V2 0x080000
+#define HWCAP_DX_REGS 0x100000
+
+unsigned long cpu_id, cpu_rev, cpu_cfgid;
+char cpu_series;
+char *endianness = NULL;
+
+unsigned int __atags_pointer __initdata;
+unsigned int elf_hwcap;
+EXPORT_SYMBOL(elf_hwcap);
+
+/*
+ * The following string table, must sync with HWCAP_xx bitmask,
+ * which is defined in <asm/procinfo.h>
+ */
+static const char *hwcap_str[] = {
+ "mfusr_pc",
+ "perf1",
+ "perf2",
+ "fpu",
+ "audio",
+ "16b",
+ "string",
+ "reduced_regs",
+ "video",
+ "encrypt",
+ "edm",
+ "lmdma",
+ "pfm",
+ "hsmp",
+ "trace",
+ "div",
+ "mac",
+ "l2c",
+ "dx_regs",
+ "v2",
+ NULL,
+};
+
+#ifdef CONFIG_CPU_DCACHE_WRITETHROUGH
+#define WRITE_METHOD "write through"
+#else
+#define WRITE_METHOD "write back"
+#endif
+
+struct cache_info L1_cache_info[2];
+static void __init dump_cpu_info(int cpu)
+{
+ int i, p = 0;
+ char str[sizeof(hwcap_str) + 16];
+
+ for (i = 0; hwcap_str[i]; i++) {
+ if (elf_hwcap & (1 << i)) {
+ sprintf(str + p, "%s ", hwcap_str[i]);
+ p += strlen(hwcap_str[i]) + 1;
+ }
+ }
+
+ pr_info("CPU%d Features: %s\n", cpu, str);
+
+ L1_cache_info[ICACHE].ways = CACHE_WAY(ICACHE);
+ L1_cache_info[ICACHE].line_size = CACHE_LINE_SIZE(ICACHE);
+ L1_cache_info[ICACHE].sets = CACHE_SET(ICACHE);
+ L1_cache_info[ICACHE].size =
+ L1_cache_info[ICACHE].ways * L1_cache_info[ICACHE].line_size *
+ L1_cache_info[ICACHE].sets / 1024;
+ pr_info("L1I:%dKB/%dS/%dW/%dB\n", L1_cache_info[ICACHE].size,
+ L1_cache_info[ICACHE].sets, L1_cache_info[ICACHE].ways,
+ L1_cache_info[ICACHE].line_size);
+ L1_cache_info[DCACHE].ways = CACHE_WAY(DCACHE);
+ L1_cache_info[DCACHE].line_size = CACHE_LINE_SIZE(DCACHE);
+ L1_cache_info[DCACHE].sets = CACHE_SET(DCACHE);
+ L1_cache_info[DCACHE].size =
+ L1_cache_info[DCACHE].ways * L1_cache_info[DCACHE].line_size *
+ L1_cache_info[DCACHE].sets / 1024;
+ pr_info("L1D:%dKB/%dS/%dW/%dB\n", L1_cache_info[DCACHE].size,
+ L1_cache_info[DCACHE].sets, L1_cache_info[DCACHE].ways,
+ L1_cache_info[DCACHE].line_size);
+ pr_info("L1 D-Cache is %s\n", WRITE_METHOD);
+ if (L1_cache_info[DCACHE].size != L1_CACHE_BYTES)
+ pr_crit
+ ("The cache line size(%d) of this processor is not the same as L1_CACHE_BYTES(%d).\n",
+ L1_cache_info[DCACHE].size, L1_CACHE_BYTES);
+#ifdef CONFIG_CPU_CACHE_ALIASING
+ {
+ int aliasing_num;
+ aliasing_num =
+ L1_cache_info[ICACHE].size * 1024 / PAGE_SIZE /
+ L1_cache_info[ICACHE].ways;
+ L1_cache_info[ICACHE].aliasing_num = aliasing_num;
+ L1_cache_info[ICACHE].aliasing_mask =
+ (aliasing_num - 1) << PAGE_SHIFT;
+ aliasing_num =
+ L1_cache_info[DCACHE].size * 1024 / PAGE_SIZE /
+ L1_cache_info[DCACHE].ways;
+ L1_cache_info[DCACHE].aliasing_num = aliasing_num;
+ L1_cache_info[DCACHE].aliasing_mask =
+ (aliasing_num - 1) << PAGE_SHIFT;
+ }
+#endif
+}
+
+static void __init setup_cpuinfo(void)
+{
+ unsigned long tmp = 0, cpu_name;
+
+ cpu_dcache_inval_all();
+ cpu_icache_inval_all();
+ __nds32__isb();
+
+ cpu_id = (__nds32__mfsr(NDS32_SR_CPU_VER) & CPU_VER_mskCPUID) >> CPU_VER_offCPUID;
+ cpu_name = ((cpu_id) & 0xf0) >> 4;
+ cpu_series = cpu_name ? cpu_name - 10 + 'A' : 'N';
+ cpu_id = cpu_id & 0xf;
+ cpu_rev = (__nds32__mfsr(NDS32_SR_CPU_VER) & CPU_VER_mskREV) >> CPU_VER_offREV;
+ cpu_cfgid = (__nds32__mfsr(NDS32_SR_CPU_VER) & CPU_VER_mskCFGID) >> CPU_VER_offCFGID;
+
+ pr_info("CPU:%c%ld, CPU_VER 0x%08x(id %lu, rev %lu, cfg %lu)\n",
+ cpu_series, cpu_id, __nds32__mfsr(NDS32_SR_CPU_VER), cpu_id, cpu_rev, cpu_cfgid);
+
+ elf_hwcap |= HWCAP_MFUSR_PC;
+
+ if (((__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskBASEV) >> MSC_CFG_offBASEV) == 0) {
+ if (__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskDIV)
+ elf_hwcap |= HWCAP_DIV;
+
+ if ((__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskMAC)
+ || (cpu_id == 12 && cpu_rev < 4))
+ elf_hwcap |= HWCAP_MAC;
+ } else {
+ elf_hwcap |= HWCAP_V2;
+ elf_hwcap |= HWCAP_DIV;
+ elf_hwcap |= HWCAP_MAC;
+ }
+
+ if (cpu_cfgid & 0x0001)
+ elf_hwcap |= HWCAP_EXT;
+
+ if (cpu_cfgid & 0x0002)
+ elf_hwcap |= HWCAP_BASE16;
+
+ if (cpu_cfgid & 0x0004)
+ elf_hwcap |= HWCAP_EXT2;
+
+ if (cpu_cfgid & 0x0008)
+ elf_hwcap |= HWCAP_FPU;
+
+ if (cpu_cfgid & 0x0010)
+ elf_hwcap |= HWCAP_STRING;
+
+ if (__nds32__mfsr(NDS32_SR_MMU_CFG) & MMU_CFG_mskDE)
+ endianness = "MSB";
+ else
+ endianness = "LSB";
+
+ if (__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskEDM)
+ elf_hwcap |= HWCAP_EDM;
+
+ if (__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskLMDMA)
+ elf_hwcap |= HWCAP_LMDMA;
+
+ if (__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskPFM)
+ elf_hwcap |= HWCAP_PFM;
+
+ if (__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskHSMP)
+ elf_hwcap |= HWCAP_HSMP;
+
+ if (__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskTRACE)
+ elf_hwcap |= HWCAP_TRACE;
+
+ if (__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskAUDIO)
+ elf_hwcap |= HWCAP_AUDIO;
+
+ if (__nds32__mfsr(NDS32_SR_MSC_CFG) & MSC_CFG_mskL2C)
+ elf_hwcap |= HWCAP_L2C;
+
+ tmp = __nds32__mfsr(NDS32_SR_CACHE_CTL);
+ if (!IS_ENABLED(CONFIG_CPU_DCACHE_DISABLE))
+ tmp |= CACHE_CTL_mskDC_EN;
+
+ if (!IS_ENABLED(CONFIG_CPU_ICACHE_DISABLE))
+ tmp |= CACHE_CTL_mskIC_EN;
+ __nds32__mtsr_isb(tmp, NDS32_SR_CACHE_CTL);
+
+ dump_cpu_info(smp_processor_id());
+}
+
+static void __init setup_memory(void)
+{
+ unsigned long ram_start_pfn;
+ unsigned long free_ram_start_pfn;
+ phys_addr_t memory_start, memory_end;
+ struct memblock_region *region;
+
+ memory_end = memory_start = 0;
+
+ /* Find main memory where is the kernel */
+ for_each_memblock(memory, region) {
+ memory_start = region->base;
+ memory_end = region->base + region->size;
+ pr_info("%s: Memory: 0x%x-0x%x\n", __func__,
+ memory_start, memory_end);
+ }
+
+ if (!memory_end) {
+ panic("No memory!");
+ }
+
+ ram_start_pfn = PFN_UP(memblock_start_of_DRAM());
+ /* free_ram_start_pfn is first page after kernel */
+ free_ram_start_pfn = PFN_UP(__pa(&_end));
+ max_pfn = PFN_DOWN(memblock_end_of_DRAM());
+ /* it could update max_pfn */
+ if (max_pfn - ram_start_pfn <= MAXMEM_PFN)
+ max_low_pfn = max_pfn;
+ else {
+ max_low_pfn = MAXMEM_PFN + ram_start_pfn;
+ if (!IS_ENABLED(CONFIG_HIGHMEM))
+ max_pfn = MAXMEM_PFN + ram_start_pfn;
+ }
+ /* high_memory is related with VMALLOC */
+ high_memory = (void *)__va(max_low_pfn * PAGE_SIZE);
+ min_low_pfn = free_ram_start_pfn;
+
+ /*
+ * initialize the boot-time allocator (with low memory only).
+ *
+ * This makes the memory from the end of the kernel to the end of
+ * RAM usable.
+ */
+ memblock_set_bottom_up(true);
+ memblock_reserve(PFN_PHYS(ram_start_pfn), PFN_PHYS(free_ram_start_pfn - ram_start_pfn));
+
+ early_init_fdt_reserve_self();
+ early_init_fdt_scan_reserved_mem();
+
+ memblock_dump_all();
+}
+
+void __init setup_arch(char **cmdline_p)
+{
+ early_init_devtree( __dtb_start);
+
+ setup_cpuinfo();
+
+ init_mm.start_code = (unsigned long)&_stext;
+ init_mm.end_code = (unsigned long)&_etext;
+ init_mm.end_data = (unsigned long)&_edata;
+ init_mm.brk = (unsigned long)&_end;
+
+ /* setup bootmem allocator */
+ setup_memory();
+
+ /* paging_init() sets up the MMU and marks all pages as reserved */
+ paging_init();
+
+ /* use generic way to parse */
+ parse_early_param();
+
+ unflatten_and_copy_device_tree();
+
+ if(IS_ENABLED(CONFIG_VT)) {
+ if(IS_ENABLED(CONFIG_DUMMY_CONSOLE))
+ conswitchp = &dummy_con;
+ }
+
+ *cmdline_p = boot_command_line;
+ early_trap_init();
+}
+
+static int c_show(struct seq_file *m, void *v)
+{
+ int i;
+
+ seq_printf(m, "Processor\t: %c%ld (id %lu, rev %lu, cfg %lu)\n",
+ cpu_series, cpu_id, cpu_id, cpu_rev, cpu_cfgid);
+
+ seq_printf(m, "L1I\t\t: %luKB/%luS/%luW/%luB\n",
+ CACHE_SET(ICACHE) * CACHE_WAY(ICACHE) *
+ CACHE_LINE_SIZE(ICACHE) / 1024, CACHE_SET(ICACHE),
+ CACHE_WAY(ICACHE), CACHE_LINE_SIZE(ICACHE));
+
+ seq_printf(m, "L1D\t\t: %luKB/%luS/%luW/%luB\n",
+ CACHE_SET(DCACHE) * CACHE_WAY(DCACHE) *
+ CACHE_LINE_SIZE(DCACHE) / 1024, CACHE_SET(DCACHE),
+ CACHE_WAY(DCACHE), CACHE_LINE_SIZE(DCACHE));
+
+ seq_printf(m, "BogoMIPS\t: %lu.%02lu\n",
+ loops_per_jiffy / (500000 / HZ),
+ (loops_per_jiffy / (5000 / HZ)) % 100);
+
+ /* dump out the processor features */
+ seq_puts(m, "Features\t: ");
+
+ for (i = 0; hwcap_str[i]; i++)
+ if (elf_hwcap & (1 << i))
+ seq_printf(m, "%s ", hwcap_str[i]);
+
+ seq_puts(m, "\n\n");
+
+ return 0;
+}
+
+static void *c_start(struct seq_file *m, loff_t * pos)
+{
+ return *pos < 1 ? (void *)1 : NULL;
+}
+
+static void *c_next(struct seq_file *m, void *v, loff_t * pos)
+{
+ ++*pos;
+ return NULL;
+}
+
+static void c_stop(struct seq_file *m, void *v)
+{
+}
+
+struct seq_operations cpuinfo_op = {
+ .start = c_start,
+ .next = c_next,
+ .stop = c_stop,
+ .show = c_show
+};
--
2.16.1