[PATCH] powerpc: Add back support for booting from BootX (#2)

ARCH=powerpc couldn't boot from BootX as it uses a "different" way of
getting in the kernel. This patch adds the necessary trampolines,
creating a flattened device-tree from the tree passed from MacOS, and
initializing the btext engine early for really-early debugging.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

3 files changed, 563 insertions, 0 deletions

diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S
index fdd34dbd8797..6359e364fe66 100644
--- a/arch/powerpc/kernel/head_32.S
+++ b/arch/powerpc/kernel/head_32.S
@@ -125,6 +125,19 @@ __start:
         bl      prom_init
         trap
 
+/*
+ * Check for BootX signature when supporting PowerMac and branch to
+ * appropriate trampoline if it's present
+ */
+#ifdef CONFIG_PPC_PMAC
+1:      lis     r31,0x426f
+        ori     r31,r31,0x6f58
+        cmpw    0,r3,r31
+        bne     1f
+        bl      bootx_init
+        trap
+#endif /* CONFIG_PPC_PMAC */
+
 1:      mr      r31,r3                  /* save parameters */
         mr      r30,r4
         li      r24,0                   /* cpu # */
diff --git a/arch/powerpc/platforms/powermac/Makefile b/arch/powerpc/platforms/powermac/Makefile
index 3e5370eeb1b7..faa1a2c82bcf 100644
--- a/arch/powerpc/platforms/powermac/Makefile
+++ b/arch/powerpc/platforms/powermac/Makefile
@@ -1,3 +1,5 @@
+CFLAGS_bootx_init.o             += -fPIC
+
 obj-y                           += pic.o setup.o time.o feature.o pci.o \
                                    sleep.o low_i2c.o cache.o
 obj-$(CONFIG_PMAC_BACKLIGHT)    += backlight.o
@@ -6,5 +8,6 @@ obj-$(CONFIG_CPU_FREQ_PMAC64)	+= cpufreq_64.o
 obj-$(CONFIG_NVRAM)             += nvram.o
 # ppc64 pmac doesn't define CONFIG_NVRAM but needs nvram stuff
 obj-$(CONFIG_PPC64)             += nvram.o
+obj-$(CONFIG_PPC32)             += bootx_init.o
 obj-$(CONFIG_SMP)               += smp.o
 obj-$(CONFIG_PPC_MERGE)         += udbg_scc.o udbg_adb.o
diff --git a/arch/powerpc/platforms/powermac/bootx_init.c b/arch/powerpc/platforms/powermac/bootx_init.c
new file mode 100644
index 000000000000..fa8b4d7b5ded
--- /dev/null
+++ b/arch/powerpc/platforms/powermac/bootx_init.c
@@ -0,0 +1,547 @@
+/*
+ *  Early boot support code for BootX bootloader
+ *
+ *  Copyright (C) 2005 Ben. Herrenschmidt (benh@kernel.crashing.org)
+ *
+ *  This program is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU General Public License
+ *  as published by the Free Software Foundation; either version
+ *  2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/config.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/init.h>
+#include <linux/version.h>
+#include <asm/sections.h>
+#include <asm/prom.h>
+#include <asm/page.h>
+#include <asm/bootx.h>
+#include <asm/bootinfo.h>
+#include <asm/btext.h>
+#include <asm/io.h>
+
+#undef DEBUG
+#define SET_BOOT_BAT
+
+#ifdef DEBUG
+#define DBG(fmt...) do { bootx_printf(fmt); } while(0)
+#else
+#define DBG(fmt...) do { } while(0)
+#endif
+
+extern void __start(unsigned long r3, unsigned long r4, unsigned long r5);
+
+static unsigned long __initdata bootx_dt_strbase;
+static unsigned long __initdata bootx_dt_strend;
+static unsigned long __initdata bootx_node_chosen;
+static boot_infos_t * __initdata bootx_info;
+static char __initdata bootx_disp_path[256];
+
+/* Is boot-info compatible ? */
+#define BOOT_INFO_IS_COMPATIBLE(bi) \
+        ((bi)->compatible_version <= BOOT_INFO_VERSION)
+#define BOOT_INFO_IS_V2_COMPATIBLE(bi)  ((bi)->version >= 2)
+#define BOOT_INFO_IS_V4_COMPATIBLE(bi)  ((bi)->version >= 4)
+
+#ifdef CONFIG_BOOTX_TEXT
+static void __init bootx_printf(const char *format, ...)
+{
+        const char *p, *q, *s;
+        va_list args;
+        unsigned long v;
+
+        va_start(args, format);
+        for (p = format; *p != 0; p = q) {
+                for (q = p; *q != 0 && *q != '\n' && *q != '%'; ++q)
+                        ;
+                if (q > p)
+                        btext_drawtext(p, q - p);
+                if (*q == 0)
+                        break;
+                if (*q == '\n') {
+                        ++q;
+                        btext_flushline();
+                        btext_drawstring("\r\n");
+                        btext_flushline();
+                        continue;
+                }
+                ++q;
+                if (*q == 0)
+                        break;
+                switch (*q) {
+                case 's':
+                        ++q;
+                        s = va_arg(args, const char *);
+                        if (s == NULL)
+                                s = "<NULL>";
+                        btext_drawstring(s);
+                        break;
+                case 'x':
+                        ++q;
+                        v = va_arg(args, unsigned long);
+                        btext_drawhex(v);
+                        break;
+                }
+        }
+}
+#else /* CONFIG_BOOTX_TEXT */
+static void __init bootx_printf(const char *format, ...) {}
+#endif /* CONFIG_BOOTX_TEXT */
+
+static void * __init bootx_early_getprop(unsigned long base,
+                                         unsigned long node,
+                                         char *prop)
+{
+        struct bootx_dt_node *np = (struct bootx_dt_node *)(base + node);
+        u32 *ppp = &np->properties;
+
+        while(*ppp) {
+                struct bootx_dt_prop *pp =
+                        (struct bootx_dt_prop *)(base + *ppp);
+
+                if (strcmp((char *)((unsigned long)pp->name + base),
+                           prop) == 0) {
+                        return (void *)((unsigned long)pp->value + base);
+                }
+                ppp = &pp->next;
+        }
+        return NULL;
+}
+
+#define dt_push_token(token, mem) \
+        do { \
+                *(mem) = _ALIGN_UP(*(mem),4); \
+                *((u32 *)*(mem)) = token; \
+                *(mem) += 4; \
+        } while(0)
+
+static unsigned long __init bootx_dt_find_string(char *str)
+{
+        char *s, *os;
+
+        s = os = (char *)bootx_dt_strbase;
+        s += 4;
+        while (s <  (char *)bootx_dt_strend) {
+                if (strcmp(s, str) == 0)
+                        return s - os;
+                s += strlen(s) + 1;
+        }
+        return 0;
+}
+
+static void __init bootx_dt_add_prop(char *name, void *data, int size,
+                                  unsigned long *mem_end)
+{
+        unsigned long soff = bootx_dt_find_string(name);
+        if (data == NULL)
+                size = 0;
+        if (soff == 0) {
+                bootx_printf("WARNING: Can't find string index for <%s>\n",
+                             name);
+                return;
+        }
+        if (size > 0x20000) {
+                bootx_printf("WARNING: ignoring large property ");
+                bootx_printf("%s length 0x%x\n", name, size);
+                return;
+        }
+        dt_push_token(OF_DT_PROP, mem_end);
+        dt_push_token(size, mem_end);
+        dt_push_token(soff, mem_end);
+
+        /* push property content */
+        if (size && data) {
+                memcpy((void *)*mem_end, data, size);
+                *mem_end = _ALIGN_UP(*mem_end + size, 4);
+        }
+}
+
+static void __init bootx_add_chosen_props(unsigned long base,
+                                          unsigned long *mem_end)
+{
+        u32 val = _MACH_Pmac;
+
+        bootx_dt_add_prop("linux,platform", &val, 4, mem_end);
+
+        if (bootx_info->kernelParamsOffset) {
+                char *args = (char *)((unsigned long)bootx_info) +
+                        bootx_info->kernelParamsOffset;
+                bootx_dt_add_prop("bootargs", args, strlen(args) + 1, mem_end);
+        }
+        if (bootx_info->ramDisk) {
+                val = ((unsigned long)bootx_info) + bootx_info->ramDisk;
+                bootx_dt_add_prop("linux,initrd-start", &val, 4, mem_end);
+                val += bootx_info->ramDiskSize;
+                bootx_dt_add_prop("linux,initrd-end", &val, 4, mem_end);
+        }
+        if (strlen(bootx_disp_path))
+                bootx_dt_add_prop("linux,stdout-path", bootx_disp_path,
+                                  strlen(bootx_disp_path) + 1, mem_end);
+}
+
+static void __init bootx_add_display_props(unsigned long base,
+                                           unsigned long *mem_end)
+{
+        bootx_dt_add_prop("linux,boot-display", NULL, 0, mem_end);
+        bootx_dt_add_prop("linux,opened", NULL, 0, mem_end);
+}
+
+static void __init bootx_dt_add_string(char *s, unsigned long *mem_end)
+{
+        unsigned int l = strlen(s) + 1;
+        memcpy((void *)*mem_end, s, l);
+        bootx_dt_strend = *mem_end = *mem_end + l;
+}
+
+static void __init bootx_scan_dt_build_strings(unsigned long base,
+                                               unsigned long node,
+                                               unsigned long *mem_end)
+{
+        struct bootx_dt_node *np = (struct bootx_dt_node *)(base + node);
+        u32 *cpp, *ppp = &np->properties;
+        unsigned long soff;
+        char *namep;
+
+        /* Keep refs to known nodes */
+        namep = np->full_name ? (char *)(base + np->full_name) : NULL;
+        if (namep == NULL) {
+                bootx_printf("Node without a full name !\n");
+                namep = "";
+        }
+        DBG("* strings: %s\n", namep);
+
+        if (!strcmp(namep, "/chosen")) {
+                DBG(" detected /chosen ! adding properties names !\n");
+                bootx_dt_add_string("linux,platform", mem_end);
+                bootx_dt_add_string("linux,stdout-path", mem_end);
+                bootx_dt_add_string("linux,initrd-start", mem_end);
+                bootx_dt_add_string("linux,initrd-end", mem_end);
+                bootx_dt_add_string("bootargs", mem_end);
+                bootx_node_chosen = node;
+        }
+        if (node == bootx_info->dispDeviceRegEntryOffset) {
+                DBG(" detected display ! adding properties names !\n");
+                bootx_dt_add_string("linux,boot-display", mem_end);
+                bootx_dt_add_string("linux,opened", mem_end);
+                strncpy(bootx_disp_path, namep, 255);
+        }
+
+        /* get and store all property names */
+        while (*ppp) {
+                struct bootx_dt_prop *pp =
+                        (struct bootx_dt_prop *)(base + *ppp);
+
+                namep = pp->name ? (char *)(base + pp->name) : NULL;
+                if (namep == NULL || strcmp(namep, "name") == 0)
+                        goto next;
+                /* get/create string entry */
+                soff = bootx_dt_find_string(namep);
+                if (soff == 0)
+                        bootx_dt_add_string(namep, mem_end);
+        next:
+                ppp = &pp->next;
+        }
+
+        /* do all our children */
+        cpp = &np->child;
+        while(*cpp) {
+                np = (struct bootx_dt_node *)(base + *cpp);
+                bootx_scan_dt_build_strings(base, *cpp, mem_end);
+                cpp = &np->sibling;
+        }
+}
+
+static void __init bootx_scan_dt_build_struct(unsigned long base,
+                                              unsigned long node,
+                                              unsigned long *mem_end)
+{
+        struct bootx_dt_node *np = (struct bootx_dt_node *)(base + node);
+        u32 *cpp, *ppp = &np->properties;
+        char *namep, *p, *ep, *lp;
+        int l;
+
+        dt_push_token(OF_DT_BEGIN_NODE, mem_end);
+
+        /* get the node's full name */
+        namep = np->full_name ? (char *)(base + np->full_name) : NULL;
+        if (namep == NULL)
+                namep = "";
+        l = strlen(namep);
+
+        DBG("* struct: %s\n", namep);
+
+        /* Fixup an Apple bug where they have bogus \0 chars in the
+         * middle of the path in some properties, and extract
+         * the unit name (everything after the last '/').
+         */
+        memcpy((void *)*mem_end, namep, l + 1);
+        namep = (char *)*mem_end;
+        for (lp = p = namep, ep = namep + l; p < ep; p++) {
+                if (*p == '/')
+                        lp = namep;
+                else if (*p != 0)
+                        *lp++ = *p;
+        }
+        *lp = 0;
+        *mem_end = _ALIGN_UP((unsigned long)lp + 1, 4);
+
+        /* get and store all properties */
+        while (*ppp) {
+                struct bootx_dt_prop *pp =
+                        (struct bootx_dt_prop *)(base + *ppp);
+
+                namep = pp->name ? (char *)(base + pp->name) : NULL;
+                /* Skip "name" */
+                if (namep == NULL || !strcmp(namep, "name"))
+                        goto next;
+                /* Skip "bootargs" in /chosen too as we replace it */
+                if (node == bootx_node_chosen && !strcmp(namep, "bootargs"))
+                        goto next;
+
+                /* push property head */
+                bootx_dt_add_prop(namep,
+                                  pp->value ? (void *)(base + pp->value): NULL,
+                                  pp->length, mem_end);
+        next:
+                ppp = &pp->next;
+        }
+
+        if (node == bootx_node_chosen)
+                bootx_add_chosen_props(base, mem_end);
+        if (node == bootx_info->dispDeviceRegEntryOffset)
+                bootx_add_display_props(base, mem_end);
+
+        /* do all our children */
+        cpp = &np->child;
+        while(*cpp) {
+                np = (struct bootx_dt_node *)(base + *cpp);
+                bootx_scan_dt_build_struct(base, *cpp, mem_end);
+                cpp = &np->sibling;
+        }
+
+        dt_push_token(OF_DT_END_NODE, mem_end);
+}
+
+static unsigned long __init bootx_flatten_dt(unsigned long start)
+{
+        boot_infos_t *bi = bootx_info;
+        unsigned long mem_start, mem_end;
+        struct boot_param_header *hdr;
+        unsigned long base;
+        u64 *rsvmap;
+
+        /* Start using memory after the big blob passed by BootX, get
+         * some space for the header
+         */
+        mem_start = mem_end = _ALIGN_UP(((unsigned long)bi) + start, 4);
+        DBG("Boot params header at: %x\n", mem_start);
+        hdr = (struct boot_param_header *)mem_start;
+        mem_end += sizeof(struct boot_param_header);
+        rsvmap = (u64 *)(_ALIGN_UP(mem_end, 8));
+        hdr->off_mem_rsvmap = ((unsigned long)rsvmap) - mem_start;
+        mem_end = ((unsigned long)rsvmap) + 8 * sizeof(u64);
+
+        /* Get base of tree */
+        base = ((unsigned long)bi) + bi->deviceTreeOffset;
+
+        /* Build string array */
+        DBG("Building string array at: %x\n", mem_end);
+        DBG("Device Tree Base=%x\n", base);
+        bootx_dt_strbase = mem_end;
+        mem_end += 4;
+        bootx_dt_strend = mem_end;
+        bootx_scan_dt_build_strings(base, 4, &mem_end);
+        hdr->off_dt_strings = bootx_dt_strbase - mem_start;
+        hdr->dt_strings_size = bootx_dt_strend - bootx_dt_strbase;
+
+        /* Build structure */
+        mem_end = _ALIGN(mem_end, 16);
+        DBG("Building device tree structure at: %x\n", mem_end);
+        hdr->off_dt_struct = mem_end - mem_start;
+        bootx_scan_dt_build_struct(base, 4, &mem_end);
+        dt_push_token(OF_DT_END, &mem_end);
+
+        /* Finish header */
+        hdr->boot_cpuid_phys = 0;
+        hdr->magic = OF_DT_HEADER;
+        hdr->totalsize = mem_end - mem_start;
+        hdr->version = OF_DT_VERSION;
+        /* Version 16 is not backward compatible */
+        hdr->last_comp_version = 0x10;
+
+        /* Reserve the whole thing and copy the reserve map in, we
+         * also bump mem_reserve_cnt to cause further reservations to
+         * fail since it's too late.
+         */
+        mem_end = _ALIGN(mem_end, PAGE_SIZE);
+        DBG("End of boot params: %x\n", mem_end);
+        rsvmap[0] = mem_start;
+        rsvmap[1] = mem_end;
+        rsvmap[2] = 0;
+        rsvmap[3] = 0;
+
+        return (unsigned long)hdr;
+}
+
+
+#ifdef CONFIG_BOOTX_TEXT
+static void __init btext_welcome(boot_infos_t *bi)
+{
+        unsigned long flags;
+        unsigned long pvr;
+
+        bootx_printf("Welcome to Linux, kernel " UTS_RELEASE "\n");
+        bootx_printf("\nlinked at        : 0x%x", KERNELBASE);
+        bootx_printf("\nframe buffer at  : 0x%x", bi->dispDeviceBase);
+        bootx_printf(" (phys), 0x%x", bi->logicalDisplayBase);
+        bootx_printf(" (log)");
+        bootx_printf("\nklimit           : 0x%x",(unsigned long)klimit);
+        bootx_printf("\nboot_info at     : 0x%x", bi);
+        __asm__ __volatile__ ("mfmsr %0" : "=r" (flags));
+        bootx_printf("\nMSR              : 0x%x", flags);
+        __asm__ __volatile__ ("mfspr %0, 287" : "=r" (pvr));
+        bootx_printf("\nPVR              : 0x%x", pvr);
+        pvr >>= 16;
+        if (pvr > 1) {
+            __asm__ __volatile__ ("mfspr %0, 1008" : "=r" (flags));
+            bootx_printf("\nHID0             : 0x%x", flags);
+        }
+        if (pvr == 8 || pvr == 12 || pvr == 0x800c) {
+            __asm__ __volatile__ ("mfspr %0, 1019" : "=r" (flags));
+            bootx_printf("\nICTC             : 0x%x", flags);
+        }
+#ifdef DEBUG
+        bootx_printf("\n\n");
+        bootx_printf("bi->deviceTreeOffset   : 0x%x\n",
+                     bi->deviceTreeOffset);
+        bootx_printf("bi->deviceTreeSize     : 0x%x\n",
+                     bi->deviceTreeSize);
+#endif
+        bootx_printf("\n\n");
+}
+#endif /* CONFIG_BOOTX_TEXT */
+
+void __init bootx_init(unsigned long r3, unsigned long r4)
+{
+        boot_infos_t *bi = (boot_infos_t *) r4;
+        unsigned long hdr;
+        unsigned long space;
+        unsigned long ptr, x;
+        char *model;
+        unsigned long offset = reloc_offset();
+
+        reloc_got2(offset);
+
+        bootx_info = bi;
+
+        /* We haven't cleared any bss at this point, make sure
+         * what we need is initialized
+         */
+        bootx_dt_strbase = bootx_dt_strend = 0;
+        bootx_node_chosen = 0;
+        bootx_disp_path[0] = 0;
+
+        if (!BOOT_INFO_IS_V2_COMPATIBLE(bi))
+                bi->logicalDisplayBase = bi->dispDeviceBase;
+
+#ifdef CONFIG_BOOTX_TEXT
+        btext_setup_display(bi->dispDeviceRect[2] - bi->dispDeviceRect[0],
+                            bi->dispDeviceRect[3] - bi->dispDeviceRect[1],
+                            bi->dispDeviceDepth, bi->dispDeviceRowBytes,
+                            (unsigned long)bi->logicalDisplayBase);
+        btext_clearscreen();
+        btext_flushscreen();
+#endif /* CONFIG_BOOTX_TEXT */
+
+        /*
+         * Test if boot-info is compatible.  Done only in config
+         * CONFIG_BOOTX_TEXT since there is nothing much we can do
+         * with an incompatible version, except display a message
+         * and eventually hang the processor...
+         *
+         * I'll try to keep enough of boot-info compatible in the
+         * future to always allow display of this message;
+         */
+        if (!BOOT_INFO_IS_COMPATIBLE(bi)) {
+                bootx_printf(" !!! WARNING - Incompatible version"
+                             " of BootX !!!\n\n\n");
+                for (;;)
+                        ;
+        }
+        if (bi->architecture != BOOT_ARCH_PCI) {
+                bootx_printf(" !!! WARNING - Usupported machine"
+                             " architecture !\n");
+                for (;;)
+                        ;
+        }
+
+#ifdef CONFIG_BOOTX_TEXT
+        btext_welcome(bi);
+#endif
+        /* New BootX enters kernel with MMU off, i/os are not allowed
+         * here. This hack will have been done by the boostrap anyway.
+         */
+        if (bi->version < 4) {
+                /*
+                 * XXX If this is an iMac, turn off the USB controller.
+                 */
+                model = (char *) bootx_early_getprop(r4 + bi->deviceTreeOffset,
+                                                     4, "model");
+                if (model
+                    && (strcmp(model, "iMac,1") == 0
+                        || strcmp(model, "PowerMac1,1") == 0)) {
+                        bootx_printf("iMac,1 detected, shutting down USB \n");
+                        out_le32((unsigned *)0x80880008, 1);    /* XXX */
+                }
+        }
+
+        /* Get a pointer that points above the device tree, args, ramdisk,
+         * etc... to use for generating the flattened tree
+         */
+        if (bi->version < 5) {
+                space = bi->deviceTreeOffset + bi->deviceTreeSize;
+                if (bi->ramDisk)
+                        space = bi->ramDisk + bi->ramDiskSize;
+        } else
+                space = bi->totalParamsSize;
+
+        bootx_printf("Total space used by parameters & ramdisk: %x \n", space);
+
+        /* New BootX will have flushed all TLBs and enters kernel with
+         * MMU switched OFF, so this should not be useful anymore.
+         */
+        if (bi->version < 4) {
+                bootx_printf("Touching pages...\n");
+
+                /*
+                 * Touch each page to make sure the PTEs for them
+                 * are in the hash table - the aim is to try to avoid
+                 * getting DSI exceptions while copying the kernel image.
+                 */
+                for (ptr = ((unsigned long) &_stext) & PAGE_MASK;
+                     ptr < (unsigned long)bi + space; ptr += PAGE_SIZE)
+                        x = *(volatile unsigned long *)ptr;
+        }
+
+        /* Ok, now we need to generate a flattened device-tree to pass
+         * to the kernel
+         */
+        bootx_printf("Preparing boot params...\n");
+
+        hdr = bootx_flatten_dt(space);
+
+#ifdef CONFIG_BOOTX_TEXT
+#ifdef SET_BOOT_BAT
+        bootx_printf("Preparing BAT...\n");
+        btext_prepare_BAT();
+#else
+        btext_unmap();
+#endif
+#endif
+
+        reloc_got2(-offset);
+
+        __start(hdr, KERNELBASE + offset, 0);
+}