[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>

diff --git a/Documentation/powerpc/booting-without-of.txt b/Documentation/powerpc/booting-without-of.txt
index 76733a3962f05ae30aec247db6a08bbf353df13c..20e0e6cb0347bf51d167b29f340f8c31df6f3f38 100644 (file)
--- a/Documentation/powerpc/booting-without-of.txt
+++ b/Documentation/powerpc/booting-without-of.txt
@@ -50,7 +50,7 @@ Table of Contents
       g) Freescale SOC SEC Security Engines
       h) Board Control and Status (BCSR)
       i) Freescale QUICC Engine module (QE)
       g) Freescale SOC SEC Security Engines
       h) Board Control and Status (BCSR)
       i) Freescale QUICC Engine module (QE)

-      j) Flash chip nodes
+      j) CFI or JEDEC memory-mapped NOR flash

       k) Global Utilities Block
 
   VII - Specifying interrupt information for devices
       k) Global Utilities Block
 
   VII - Specifying interrupt information for devices


@@ -1757,45 +1757,69 @@ platforms are moved over to use the flattened-device-tree model.
                };
        };
 
                };
        };
 

-    j) Flash chip nodes
+   j) CFI or JEDEC memory-mapped NOR flash

 
     Flash chips (Memory Technology Devices) are often used for solid state
     file systems on embedded devices.
 
 
     Flash chips (Memory Technology Devices) are often used for solid state
     file systems on embedded devices.
 

-    Required properties:
+     - compatible : should contain the specific model of flash chip(s)
+       used, if known, followed by either "cfi-flash" or "jedec-flash"
+     - reg : Address range of the flash chip
+     - bank-width : Width (in bytes) of the flash bank.  Equal to the
+       device width times the number of interleaved chips.
+     - device-width : (optional) Width of a single flash chip.  If
+       omitted, assumed to be equal to 'bank-width'.
+     - #address-cells, #size-cells : Must be present if the flash has
+       sub-nodes representing partitions (see below).  In this case
+       both #address-cells and #size-cells must be equal to 1.
+
+    For JEDEC compatible devices, the following additional properties
+    are defined:
+
+     - vendor-id : Contains the flash chip's vendor id (1 byte).
+     - device-id : Contains the flash chip's device id (1 byte).
+
+    In addition to the information on the flash bank itself, the
+    device tree may optionally contain additional information
+    describing partitions of the flash address space.  This can be
+    used on platforms which have strong conventions about which
+    portions of the flash are used for what purposes, but which don't
+    use an on-flash partition table such as RedBoot.
+
+    Each partition is represented as a sub-node of the flash device.
+    Each node's name represents the name of the corresponding
+    partition of the flash device.
+
+    Flash partitions
+     - reg : The partition's offset and size within the flash bank.
+     - label : (optional) The label / name for this flash partition.
+       If omitted, the label is taken from the node name (excluding
+       the unit address).
+     - read-only : (optional) This parameter, if present, is a hint to
+       Linux that this flash partition should only be mounted
+       read-only.  This is usually used for flash partitions
+       containing early-boot firmware images or data which should not
+       be clobbered.

 
 

-     - device_type : has to be "rom"
-     - compatible : Should specify what this flash device is compatible with.
-       Currently, this is most likely to be "direct-mapped" (which
-       corresponds to the MTD physmap mapping driver).
-     - reg : Offset and length of the register set (or memory mapping) for
-       the device.
-     - bank-width : Width of the flash data bus in bytes. Required
-       for the NOR flashes (compatible == "direct-mapped" and others) ONLY.
-
-    Recommended properties :
-
-     - partitions : Several pairs of 32-bit values where the first value is
-       partition's offset from the start of the device and the second one is
-       partition size in bytes with LSB used to signify a read only
-       partition (so, the partition size should always be an even number).
-     - partition-names : The list of concatenated zero terminated strings
-       representing the partition names.
-     - probe-type : The type of probe which should be done for the chip
-       (JEDEC vs CFI actually). Valid ONLY for NOR flashes.
-
-   Example:
+    Example:

 
 

-       flash@ff000000 {
-               device_type = "rom";
-               compatible = "direct-mapped";
-               probe-type = "CFI";
-               reg = <ff000000 01000000>;
-               bank-width = <4>;
-               partitions = <00000000 00f80000
-                             00f80000 00080001>;
-               partition-names = "fs\0firmware";
-       };
+       flash@ff000000 {
+               compatible = "amd,am29lv128ml", "cfi-flash";
+               reg = <ff000000 01000000>;
+               bank-width = <4>;
+               device-width = <1>;
+               #address-cells = <1>;
+               #size-cells = <1>;
+               fs@0 {
+                       label = "fs";
+                       reg = <0 f80000>;
+               };
+               firmware@f80000 {
+                       label ="firmware";
+                       reg = <f80000 80000>;
+                       read-only;
+               };
+       };

 
    k) Global Utilities Block
 
 
    k) Global Utilities Block
 

diff --git a/arch/powerpc/boot/dts/ebony.dts b/arch/powerpc/boot/dts/ebony.dts
index 37599bda550044536a430e4e1d1fc47e37df90ce..bc259972aaa061170e40f4ce27b0dd34e5c9df04 100644 (file)
--- a/arch/powerpc/boot/dts/ebony.dts
+++ b/arch/powerpc/boot/dts/ebony.dts
@@ -138,13 +138,16 @@
                                interrupt-parent = <&UIC1>;
 
                                small-flash@0,80000 {
                                interrupt-parent = <&UIC1>;
 
                                small-flash@0,80000 {

-                                       device_type = "rom";
-                                       compatible = "direct-mapped";
-                                       probe-type = "JEDEC";
+                                       compatible = "jedec-flash";

                                        bank-width = <1>;
                                        bank-width = <1>;

-                                       partitions = <0 80000>;
-                                       partition-names = "OpenBIOS";

                                        reg = <0 80000 80000>;
                                        reg = <0 80000 80000>;

+                                       #address-cells = <1>;
+                                       #size-cells = <1>;
+                                       partition@0 {
+                                               label = "OpenBIOS";
+                                               reg = <0 80000>;
+                                               read-only;
+                                       };

                                };
 
                                ds1743@1,0 {
                                };
 
                                ds1743@1,0 {


@@ -154,14 +157,19 @@
                                };
 
                                large-flash@2,0 {
                                };
 
                                large-flash@2,0 {

-                                       device_type = "rom";
-                                       compatible = "direct-mapped";
-                                       probe-type = "JEDEC";
+                                       compatible = "jedec-flash";

                                        bank-width = <1>;
                                        bank-width = <1>;

-                                       partitions = <0 380000
-                                                     380000 80000>;
-                                       partition-names = "fs", "firmware";

                                        reg = <2 0 400000>;
                                        reg = <2 0 400000>;

+                                       #address-cells = <1>;
+                                       #size-cells = <1>;
+                                       partition@0 {
+                                               label = "fs";
+                                               reg = <0 380000>;
+                                       };
+                                       partition@380000 {
+                                               label = "firmware";
+                                               reg = <380000 80000>;
+                                       };

                                };
 
                                ir@3,0 {
                                };
 
                                ir@3,0 {

diff --git a/drivers/mtd/maps/physmap_of.c b/drivers/mtd/maps/physmap_of.c
index bbb42c35b69b9df05a108f21b0d837f80ca3d7e6..3df001bfee365fe110b7d44a07c05a196f44a27f 100644 (file)
--- 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>
  *
  * 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
  * 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
        struct map_info         map;
        struct resource         *res;
 #ifdef CONFIG_MTD_PARTITIONS

-       int                     nr_parts;

        struct mtd_partition    *parts;
 #endif
 };
 
        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
 #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");
                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;
                        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)
 {
 
 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->mtd != NULL) {
 #ifdef CONFIG_MTD_PARTITIONS

-               if (info->nr_parts) {
+               if (info->parts) {

                        del_mtd_partitions(info->mtd);
                        kfree(info->parts);
                } else {
                        del_mtd_partitions(info->mtd);
                        kfree(info->parts);
                } else {


@@ -115,17 +197,51 @@ static int of_physmap_remove(struct of_device *dev)
        return 0;
 }
 
        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;
 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;
 
        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;
        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);
 
 
        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;
        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;
 
        }
        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);
 
 err_out:
        of_physmap_remove(dev);


@@ -220,6 +314,21 @@ err_out:
 }
 
 static struct of_device_id of_physmap_match[] = {
 }
 
 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"
        {
                .type           = "rom",
                .compatible     = "direct-mapped"