csky: Kernel booting

This patch add boot code. Thx boot params is all in dtb and it's
the only way to let kernel get bootloader param information.

Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>

3 files changed, 305 insertions, 0 deletions

diff --git a/arch/csky/kernel/head.S b/arch/csky/kernel/head.S
new file mode 100644
index 000000000000..9c4ec473b76b
--- /dev/null
+++ b/arch/csky/kernel/head.S
@@ -0,0 +1,77 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/linkage.h>
+#include <linux/init.h>
+#include <asm/page.h>
+#include <abi/entry.h>
+
+__HEAD
+ENTRY(_start)
+        /* set super user mode */
+        lrw     a3, DEFAULT_PSR_VALUE
+        mtcr    a3, psr
+        psrset  ee
+
+        SETUP_MMU a3
+
+        /* set stack point */
+        lrw     a3, init_thread_union + THREAD_SIZE
+        mov     sp, a3
+
+        jmpi    csky_start
+END(_start)
+
+#ifdef CONFIG_SMP
+.align 10
+ENTRY(_start_smp_secondary)
+        /* Invalid I/Dcache BTB BHT */
+        movi    a3, 7
+        lsli    a3, 16
+        addi    a3, (1<<4) | 3
+        mtcr    a3, cr17
+
+        tlbi.alls
+
+        /* setup PAGEMASK */
+        movi    a3, 0
+        mtcr    a3, cr<6, 15>
+
+        /* setup MEL0/MEL1 */
+        grs     a0, _start_smp_pc
+_start_smp_pc:
+        bmaski  a1, 13
+        andn    a0, a1
+        movi    a1, 0x00000006
+        movi    a2, 0x00001006
+        or      a1, a0
+        or      a2, a0
+        mtcr    a1, cr<2, 15>
+        mtcr    a2, cr<3, 15>
+
+        /* setup MEH */
+        mtcr    a0, cr<4, 15>
+
+        /* write TLB */
+        bgeni   a3, 28
+        mtcr    a3, cr<8, 15>
+
+        SETUP_MMU a3
+
+        /* enable MMU */
+        movi    a3, 1
+        mtcr    a3, cr18
+
+        jmpi    _goto_mmu_on
+_goto_mmu_on:
+        lrw     a3, DEFAULT_PSR_VALUE
+        mtcr    a3, psr
+        psrset  ee
+
+        /* set stack point */
+        lrw     a3, secondary_stack
+        ld.w    a3, (a3, 0)
+        mov     sp, a3
+
+        jmpi    csky_start_secondary
+END(_start_smp_secondary)
+#endif
diff --git a/arch/csky/kernel/setup.c b/arch/csky/kernel/setup.c
new file mode 100644
index 000000000000..a5e3ab1d5360
--- /dev/null
+++ b/arch/csky/kernel/setup.c
@@ -0,0 +1,162 @@
+// SPDX-License-Identifier: GPL-2.0
+// Copyright (C) 2018 Hangzhou C-SKY Microsystems co.,ltd.
+
+#include <linux/console.h>
+#include <linux/memblock.h>
+#include <linux/bootmem.h>
+#include <linux/initrd.h>
+#include <linux/of.h>
+#include <linux/of_fdt.h>
+#include <linux/start_kernel.h>
+#include <linux/dma-contiguous.h>
+#include <linux/screen_info.h>
+#include <asm/sections.h>
+#include <asm/mmu_context.h>
+#include <asm/pgalloc.h>
+
+#ifdef CONFIG_DUMMY_CONSOLE
+struct screen_info screen_info = {
+        .orig_video_lines       = 30,
+        .orig_video_cols        = 80,
+        .orig_video_mode        = 0,
+        .orig_video_ega_bx      = 0,
+        .orig_video_isVGA       = 1,
+        .orig_video_points      = 8
+};
+#endif
+
+phys_addr_t __init_memblock memblock_end_of_REG0(void)
+{
+        return (memblock.memory.regions[0].base +
+                memblock.memory.regions[0].size);
+}
+
+phys_addr_t __init_memblock memblock_start_of_REG1(void)
+{
+        return memblock.memory.regions[1].base;
+}
+
+size_t __init_memblock memblock_size_of_REG1(void)
+{
+        return memblock.memory.regions[1].size;
+}
+
+static void __init csky_memblock_init(void)
+{
+        unsigned long zone_size[MAX_NR_ZONES];
+        unsigned long zhole_size[MAX_NR_ZONES];
+        signed long size;
+
+        memblock_reserve(__pa(_stext), _end - _stext);
+#ifdef CONFIG_BLK_DEV_INITRD
+        memblock_reserve(__pa(initrd_start), initrd_end - initrd_start);
+#endif
+
+        early_init_fdt_reserve_self();
+        early_init_fdt_scan_reserved_mem();
+
+        memblock_dump_all();
+
+        memset(zone_size, 0, sizeof(zone_size));
+        memset(zhole_size, 0, sizeof(zhole_size));
+
+        min_low_pfn = PFN_UP(memblock_start_of_DRAM());
+        max_pfn     = PFN_DOWN(memblock_end_of_DRAM());
+
+        max_low_pfn = PFN_UP(memblock_end_of_REG0());
+        if (max_low_pfn == 0)
+                max_low_pfn = max_pfn;
+
+        size = max_pfn - min_low_pfn;
+
+        if (memblock.memory.cnt > 1) {
+                zone_size[ZONE_NORMAL]  =
+                        PFN_DOWN(memblock_start_of_REG1()) - min_low_pfn;
+                zhole_size[ZONE_NORMAL] =
+                        PFN_DOWN(memblock_start_of_REG1()) - max_low_pfn;
+        } else {
+                if (size <= PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET))
+                        zone_size[ZONE_NORMAL] = max_pfn - min_low_pfn;
+                else {
+                        zone_size[ZONE_NORMAL] =
+                                PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET);
+                        max_low_pfn = min_low_pfn + zone_size[ZONE_NORMAL];
+                }
+        }
+
+#ifdef CONFIG_HIGHMEM
+        size = 0;
+        if (memblock.memory.cnt > 1) {
+                size = PFN_DOWN(memblock_size_of_REG1());
+                highstart_pfn = PFN_DOWN(memblock_start_of_REG1());
+        } else {
+                size = max_pfn - min_low_pfn -
+                        PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET);
+                highstart_pfn =  min_low_pfn +
+                        PFN_DOWN(LOWMEM_LIMIT - PHYS_OFFSET_OFFSET);
+        }
+
+        if (size > 0)
+                zone_size[ZONE_HIGHMEM] = size;
+
+        highend_pfn = max_pfn;
+#endif
+        memblock_set_current_limit(PFN_PHYS(max_low_pfn));
+
+        dma_contiguous_reserve(0);
+
+        free_area_init_node(0, zone_size, min_low_pfn, zhole_size);
+}
+
+void __init setup_arch(char **cmdline_p)
+{
+        *cmdline_p = boot_command_line;
+
+        console_verbose();
+
+        pr_info("Phys. mem: %ldMB\n",
+                (unsigned long) memblock_phys_mem_size()/1024/1024);
+
+        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;
+
+        parse_early_param();
+
+        csky_memblock_init();
+
+        unflatten_and_copy_device_tree();
+
+#ifdef CONFIG_SMP
+        setup_smp();
+#endif
+
+        sparse_init();
+
+#ifdef CONFIG_HIGHMEM
+        kmap_init();
+#endif
+
+#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
+        conswitchp = &dummy_con;
+#endif
+}
+
+asmlinkage __visible void __init csky_start(unsigned int unused, void *param)
+{
+        /* Clean up bss section */
+        memset(__bss_start, 0, __bss_stop - __bss_start);
+
+        pre_trap_init();
+        pre_mmu_init();
+
+        if (param == NULL)
+                early_init_dt_scan(__dtb_start);
+        else
+                early_init_dt_scan(param);
+
+        start_kernel();
+
+        asm volatile("br .\n");
+}
diff --git a/arch/csky/kernel/vmlinux.lds.S b/arch/csky/kernel/vmlinux.lds.S
new file mode 100644
index 000000000000..ae7961b973f2
--- /dev/null
+++ b/arch/csky/kernel/vmlinux.lds.S
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <asm/vmlinux.lds.h>
+#include <asm/page.h>
+
+OUTPUT_ARCH(csky)
+ENTRY(_start)
+
+#ifndef __cskyBE__
+jiffies = jiffies_64;
+#else
+jiffies = jiffies_64 + 4;
+#endif
+
+#define VBR_BASE \
+        . = ALIGN(1024); \
+        vec_base = .; \
+        . += 512;
+
+SECTIONS
+{
+        . = PAGE_OFFSET + PHYS_OFFSET_OFFSET;
+
+        _stext = .;
+        __init_begin = .;
+        HEAD_TEXT_SECTION
+        INIT_TEXT_SECTION(PAGE_SIZE)
+        INIT_DATA_SECTION(PAGE_SIZE)
+        PERCPU_SECTION(L1_CACHE_BYTES)
+        . = ALIGN(PAGE_SIZE);
+        __init_end = .;
+
+        .text : AT(ADDR(.text) - LOAD_OFFSET) {
+                _text = .;
+                IRQENTRY_TEXT
+                SOFTIRQENTRY_TEXT
+                TEXT_TEXT
+                SCHED_TEXT
+                CPUIDLE_TEXT
+                LOCK_TEXT
+                KPROBES_TEXT
+                *(.fixup)
+                *(.gnu.warning)
+        } = 0
+        _etext = .;
+
+        /* __init_begin __init_end must be page aligned for free_initmem */
+        . = ALIGN(PAGE_SIZE);
+
+
+        _sdata = .;
+        RO_DATA_SECTION(PAGE_SIZE)
+        RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
+        _edata = .;
+
+        NOTES
+        EXCEPTION_TABLE(L1_CACHE_BYTES)
+        BSS_SECTION(L1_CACHE_BYTES, PAGE_SIZE, L1_CACHE_BYTES)
+        VBR_BASE
+        _end = . ;
+
+        STABS_DEBUG
+        DWARF_DEBUG
+
+        DISCARDS
+}