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

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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>
This commit is contained in:
David Gibson 2007-09-07 13:23:53 +10:00 committed by Paul Mackerras
parent 3c607ce2a3
commit 2099172d61
3 changed files with 248 additions and 107 deletions
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86
Documentation/powerpc/booting-without-of.txt
View File

@ -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)
j) Flash chip nodes
j) CFI or JEDEC memory-mapped NOR flash
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.
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.
- 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.
For JEDEC compatible devices, the following additional properties
are defined:
Recommended properties :
- vendor-id : Contains the flash chip's vendor id (1 byte).
- device-id : Contains the flash chip's device id (1 byte).
- 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.
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.
Example:
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@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 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.
Example:
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

30
arch/powerpc/boot/dts/ebony.dts
View File

@ -138,13 +138,16 @@
interrupt-parent = <&UIC1>;
small-flash@0,80000 {
device_type = "rom";
compatible = "direct-mapped";
probe-type = "JEDEC";
compatible = "jedec-flash";
bank-width = <1>;
partitions = <0 80000>;
partition-names = "OpenBIOS";
reg = <0 80000 80000>;
#address-cells = <1>;
#size-cells = <1>;
partition@0 {
label = "OpenBIOS";
reg = <0 80000>;
read-only;
};
};
ds1743@1,0 {
@ -154,14 +157,19 @@
};
large-flash@2,0 {
device_type = "rom";
compatible = "direct-mapped";
probe-type = "JEDEC";
compatible = "jedec-flash";
bank-width = <1>;
partitions = <0 380000
380000 80000>;
partition-names = "fs", "firmware";
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 {

239
drivers/mtd/maps/physmap_of.c
View File

@ -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);
@ -220,6 +314,21 @@ 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"