[POWERPC] Document and implement an improved flash device binding for powerpc

This replaces the binding for flash chips in booting-without-of.txt
with an clarified and improved version.  It also makes
drivers/mtd/maps/physmap_of.c recognize this new binding.  Finally it
revises the Ebony device tree source to use the new binding as an
example.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 174 insertions, 65 deletions

diff --git a/drivers/mtd/maps/physmap_of.c b/drivers/mtd/maps/physmap_of.c
index bbb42c35b69b..3df001bfee36 100644
--- a/drivers/mtd/maps/physmap_of.c
+++ b/drivers/mtd/maps/physmap_of.c
@@ -4,6 +4,9 @@
  * Copyright (C) 2006 MontaVista Software Inc.
  * Author: Vitaly Wool <vwool@ru.mvista.com>
  *
+ * Revised to handle newer style flash binding by:
+ *   Copyright (C) 2007 David Gibson, IBM Corporation.
+ *
  * 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
@@ -30,56 +33,135 @@ struct physmap_flash_info {
         struct map_info         map;
         struct resource         *res;
 #ifdef CONFIG_MTD_PARTITIONS
-        int                     nr_parts;
         struct mtd_partition    *parts;
 #endif
 };
 
-static const char *rom_probe_types[] = { "cfi_probe", "jedec_probe", "map_rom", NULL };
-#ifdef CONFIG_MTD_PARTITIONS
-static const char *part_probe_types[] = { "cmdlinepart", "RedBoot", NULL };
-#endif
-
 #ifdef CONFIG_MTD_PARTITIONS
-static int parse_flash_partitions(struct device_node *node,
-                struct mtd_partition **parts)
+static int parse_obsolete_partitions(struct of_device *dev,
+                                     struct physmap_flash_info *info,
+                                     struct device_node *dp)
 {
-        int i, plen, retval = -ENOMEM;
-        const  u32  *part;
-        const  char *name;
+        int i, plen, nr_parts;
+        const struct {
+                u32 offset, len;
+        } *part;
+        const char *names;
 
-        part = of_get_property(node, "partitions", &plen);
-        if (part == NULL)
-                goto err;
+        part = of_get_property(dp, "partitions", &plen);
+        if (!part)
+                return -ENOENT;
 
-        retval = plen / (2 * sizeof(u32));
-        *parts = kzalloc(retval * sizeof(struct mtd_partition), GFP_KERNEL);
-        if (*parts == NULL) {
+        dev_warn(&dev->dev, "Device tree uses obsolete partition map binding\n");
+
+        nr_parts = plen / sizeof(part[0]);
+
+        info->parts = kzalloc(nr_parts * sizeof(struct mtd_partition), GFP_KERNEL);
+        if (!info->parts) {
                 printk(KERN_ERR "Can't allocate the flash partition data!\n");
-                goto err;
+                return -ENOMEM;
         }
 
-        name = of_get_property(node, "partition-names", &plen);
+        names = of_get_property(dp, "partition-names", &plen);
 
-        for (i = 0; i < retval; i++) {
-                (*parts)[i].offset = *part++;
-                (*parts)[i].size   = *part & ~1;
-                if (*part++ & 1) /* bit 0 set signifies read only partition */
-                        (*parts)[i].mask_flags = MTD_WRITEABLE;
+        for (i = 0; i < nr_parts; i++) {
+                info->parts[i].offset = part->offset;
+                info->parts[i].size   = part->len & ~1;
+                if (part->len & 1) /* bit 0 set signifies read only partition */
+                        info->parts[i].mask_flags = MTD_WRITEABLE;
 
-                if (name != NULL && plen > 0) {
-                        int len = strlen(name) + 1;
+                if (names && (plen > 0)) {
+                        int len = strlen(names) + 1;
 
-                        (*parts)[i].name = (char *)name;
+                        info->parts[i].name = (char *)names;
                         plen -= len;
-                        name += len;
-                } else
-                        (*parts)[i].name = "unnamed";
+                        names += len;
+                } else {
+                        info->parts[i].name = "unnamed";
+                }
+
+                part++;
         }
-err:
-        return retval;
+
+        return nr_parts;
 }
-#endif
+
+static int __devinit process_partitions(struct physmap_flash_info *info,
+                                        struct of_device *dev)
+{
+        const char *partname;
+        static const char *part_probe_types[]
+                = { "cmdlinepart", "RedBoot", NULL };
+        struct device_node *dp = dev->node, *pp;
+        int nr_parts, i;
+
+        /* First look for RedBoot table or partitions on the command
+         * line, these take precedence over device tree information */
+        nr_parts = parse_mtd_partitions(info->mtd, part_probe_types,
+                                        &info->parts, 0);
+        if (nr_parts > 0) {
+                add_mtd_partitions(info->mtd, info->parts, nr_parts);
+                return 0;
+        }
+
+        /* First count the subnodes */
+        nr_parts = 0;
+        for (pp = dp->child; pp; pp = pp->sibling)
+                nr_parts++;
+
+        if (nr_parts) {
+                info->parts = kzalloc(nr_parts * sizeof(struct mtd_partition),
+                                      GFP_KERNEL);
+                if (!info->parts) {
+                        printk(KERN_ERR "Can't allocate the flash partition data!\n");
+                        return -ENOMEM;
+                }
+
+                for (pp = dp->child, i = 0 ; pp; pp = pp->sibling, i++) {
+                        const u32 *reg;
+                        int len;
+
+                        reg = of_get_property(pp, "reg", &len);
+                        if (!reg || (len != 2*sizeof(u32))) {
+                                dev_err(&dev->dev, "Invalid 'reg' on %s\n",
+                                        dp->full_name);
+                                kfree(info->parts);
+                                info->parts = NULL;
+                                return -EINVAL;
+                        }
+                        info->parts[i].offset = reg[0];
+                        info->parts[i].size = reg[1];
+
+                        partname = of_get_property(pp, "label", &len);
+                        if (!partname)
+                                partname = of_get_property(pp, "name", &len);
+                        info->parts[i].name = (char *)partname;
+
+                        if (of_get_property(pp, "read-only", &len))
+                                info->parts[i].mask_flags = MTD_WRITEABLE;
+                }
+        } else {
+                nr_parts = parse_obsolete_partitions(dev, info, dp);
+        }
+
+        if (nr_parts < 0)
+                return nr_parts;
+
+        if (nr_parts > 0)
+                add_mtd_partitions(info->mtd, info->parts, nr_parts);
+        else
+                add_mtd_device(info->mtd);
+
+        return 0;
+}
+#else /* MTD_PARTITIONS */
+static int __devinit process_partitions(struct physmap_flash_info *info,
+                                        struct device_node *dev)
+{
+        add_mtd_device(info->mtd);
+        return 0;
+}
+#endif /* MTD_PARTITIONS */
 
 static int of_physmap_remove(struct of_device *dev)
 {
@@ -92,7 +174,7 @@ static int of_physmap_remove(struct of_device *dev)
 
         if (info->mtd != NULL) {
 #ifdef CONFIG_MTD_PARTITIONS
-                if (info->nr_parts) {
+                if (info->parts) {
                         del_mtd_partitions(info->mtd);
                         kfree(info->parts);
                 } else {
@@ -115,17 +197,51 @@ static int of_physmap_remove(struct of_device *dev)
         return 0;
 }
 
+/* Helper function to handle probing of the obsolete "direct-mapped"
+ * compatible binding, which has an extra "probe-type" property
+ * describing the type of flash probe necessary. */
+static struct mtd_info * __devinit obsolete_probe(struct of_device *dev,
+                                                  struct map_info *map)
+{
+        struct device_node *dp = dev->node;
+        const char *of_probe;
+        struct mtd_info *mtd;
+        static const char *rom_probe_types[]
+                = { "cfi_probe", "jedec_probe", "map_rom"};
+        int i;
+
+        dev_warn(&dev->dev, "Device tree uses obsolete \"direct-mapped\" "
+                 "flash binding\n");
+
+        of_probe = of_get_property(dp, "probe-type", NULL);
+        if (!of_probe) {
+                for (i = 0; i < ARRAY_SIZE(rom_probe_types); i++) {
+                        mtd = do_map_probe(rom_probe_types[i], map);
+                        if (mtd)
+                                return mtd;
+                }
+                return NULL;
+        } else if (strcmp(of_probe, "CFI") == 0) {
+                return do_map_probe("cfi_probe", map);
+        } else if (strcmp(of_probe, "JEDEC") == 0) {
+                return do_map_probe("jedec_probe", map);
+        } else {
+                if (strcmp(of_probe, "ROM") != 0)
+                        dev_dbg(&dev->dev, "obsolete_probe: don't know probe type "
+                                "'%s', mapping as rom\n", of_probe);
+                return do_map_probe("mtd_rom", map);
+        }
+}
+
 static int __devinit of_physmap_probe(struct of_device *dev, const struct of_device_id *match)
 {
         struct device_node *dp = dev->node;
         struct resource res;
         struct physmap_flash_info *info;
-        const char **probe_type;
-        const char *of_probe;
+        const char *probe_type = (const char *)match->data;
         const u32 *width;
         int err;
 
-
         if (of_address_to_resource(dp, 0, &res)) {
                 dev_err(&dev->dev, "Can't get the flash mapping!\n");
                 err = -EINVAL;
@@ -174,21 +290,11 @@ static int __devinit of_physmap_probe(struct of_device *dev, const struct of_dev
 
         simple_map_init(&info->map);
 
-        of_probe = of_get_property(dp, "probe-type", NULL);
-        if (of_probe == NULL) {
-                probe_type = rom_probe_types;
-                for (; info->mtd == NULL && *probe_type != NULL; probe_type++)
-                        info->mtd = do_map_probe(*probe_type, &info->map);
-        } else if (!strcmp(of_probe, "CFI"))
-                info->mtd = do_map_probe("cfi_probe", &info->map);
-        else if (!strcmp(of_probe, "JEDEC"))
-                info->mtd = do_map_probe("jedec_probe", &info->map);
-        else {
-                if (strcmp(of_probe, "ROM"))
-                        dev_dbg(&dev->dev, "map_probe: don't know probe type "
-                        "'%s', mapping as rom\n", of_probe);
-                info->mtd = do_map_probe("mtd_rom", &info->map);
-        }
+        if (probe_type)
+                info->mtd = do_map_probe(probe_type, &info->map);
+        else
+                info->mtd = obsolete_probe(dev, &info->map);
+
         if (info->mtd == NULL) {
                 dev_err(&dev->dev, "map_probe failed\n");
                 err = -ENXIO;
@@ -196,19 +302,7 @@ static int __devinit of_physmap_probe(struct of_device *dev, const struct of_dev
         }
         info->mtd->owner = THIS_MODULE;
 
-#ifdef CONFIG_MTD_PARTITIONS
-        err = parse_mtd_partitions(info->mtd, part_probe_types, &info->parts, 0);
-        if (err > 0) {
-                add_mtd_partitions(info->mtd, info->parts, err);
-        } else if ((err = parse_flash_partitions(dp, &info->parts)) > 0) {
-                dev_info(&dev->dev, "Using OF partition information\n");
-                add_mtd_partitions(info->mtd, info->parts, err);
-                info->nr_parts = err;
-        } else
-#endif
-
-        add_mtd_device(info->mtd);
-        return 0;
+        return process_partitions(info, dev);
 
 err_out:
         of_physmap_remove(dev);
@@ -221,6 +315,21 @@ err_out:
 
 static struct of_device_id of_physmap_match[] = {
         {
+                .compatible     = "cfi-flash",
+                .data           = (void *)"cfi_probe",
+        },
+        {
+                /* FIXME: JEDEC chips can't be safely and reliably
+                 * probed, although the mtd code gets it right in
+                 * practice most of the time.  We should use the
+                 * vendor and device ids specified by the binding to
+                 * bypass the heuristic probe code, but the mtd layer
+                 * provides, at present, no interface for doing so
+                 * :(. */
+                .compatible     = "jedec-flash",
+                .data           = (void *)"jedec_probe",
+        },
+        {
                 .type           = "rom",
                 .compatible     = "direct-mapped"
         },