mtd: NOR flash driver for OMAP-L137/AM17x

OMAP-L137/AM17x has limited number of dedicated EMIFA
address pins, enough to interface directly to an SDRAM.
If a device such as an asynchronous flash needs to be
attached to the EMIFA, then either GPIO pins or a chip
select may be used to control the flash device's upper
address lines.

This patch adds support for the NOR flash on the OMAP-L137/
AM17x user interface daughter board using the latch-addr-flash
MTD mapping driver which allows flashes to be partially
physically addressed. The upper address lines are set by
a board specific code which is a separate patch.

Signed-off-by: David Griego <dgriego@mvista.com>
Signed-off-by: Aleksey Makarov <amakarov@ru.mvista.com>
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Savinay Dharmappa <savinay.dharmappa@ti.com>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

3 files changed, 282 insertions, 0 deletions

diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig
index 803072a71ed7..44b1f46458ca 100644
--- a/drivers/mtd/maps/Kconfig
+++ b/drivers/mtd/maps/Kconfig
@@ -552,4 +552,13 @@ config MTD_PISMO
 
           When built as a module, it will be called pismo.ko
 
+config MTD_LATCH_ADDR
+        tristate "Latch-assisted Flash Chip Support"
+        depends on MTD_COMPLEX_MAPPINGS
+        help
+          Map driver which allows flashes to be partially physically addressed
+          and have the upper address lines set by a board specific code.
+
+          If compiled as a module, it will be called latch-addr-flash.
+
 endmenu
diff --git a/drivers/mtd/maps/Makefile b/drivers/mtd/maps/Makefile
index c7869c7a6b18..08533bd5cba7 100644
--- a/drivers/mtd/maps/Makefile
+++ b/drivers/mtd/maps/Makefile
@@ -59,3 +59,4 @@ obj-$(CONFIG_MTD_RBTX4939)	+= rbtx4939-flash.o
 obj-$(CONFIG_MTD_VMU)           += vmu-flash.o
 obj-$(CONFIG_MTD_GPIO_ADDR)     += gpio-addr-flash.o
 obj-$(CONFIG_MTD_BCM963XX)      += bcm963xx-flash.o
+obj-$(CONFIG_MTD_LATCH_ADDR)    += latch-addr-flash.o
diff --git a/drivers/mtd/maps/latch-addr-flash.c b/drivers/mtd/maps/latch-addr-flash.c
new file mode 100644
index 000000000000..ee2548085334
--- /dev/null
+++ b/drivers/mtd/maps/latch-addr-flash.c
@@ -0,0 +1,272 @@
+/*
+ * Interface for NOR flash driver whose high address lines are latched
+ *
+ * Copyright © 2000 Nicolas Pitre <nico@cam.org>
+ * Copyright © 2005-2008 Analog Devices Inc.
+ * Copyright © 2008 MontaVista Software, Inc. <source@mvista.com>
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2. This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/partitions.h>
+#include <linux/platform_device.h>
+#include <linux/mtd/latch-addr-flash.h>
+#include <linux/slab.h>
+
+#define DRIVER_NAME "latch-addr-flash"
+
+struct latch_addr_flash_info {
+        struct mtd_info         *mtd;
+        struct map_info         map;
+        struct resource         *res;
+
+        void                    (*set_window)(unsigned long offset, void *data);
+        void                    *data;
+
+        /* cache; could be found out of res */
+        unsigned long           win_mask;
+
+        int                     nr_parts;
+        struct mtd_partition    *parts;
+
+        spinlock_t              lock;
+};
+
+static map_word lf_read(struct map_info *map, unsigned long ofs)
+{
+        struct latch_addr_flash_info *info;
+        map_word datum;
+
+        info = (struct latch_addr_flash_info *)map->map_priv_1;
+
+        spin_lock(&info->lock);
+
+        info->set_window(ofs, info->data);
+        datum = inline_map_read(map, info->win_mask & ofs);
+
+        spin_unlock(&info->lock);
+
+        return datum;
+}
+
+static void lf_write(struct map_info *map, map_word datum, unsigned long ofs)
+{
+        struct latch_addr_flash_info *info;
+
+        info = (struct latch_addr_flash_info *)map->map_priv_1;
+
+        spin_lock(&info->lock);
+
+        info->set_window(ofs, info->data);
+        inline_map_write(map, datum, info->win_mask & ofs);
+
+        spin_unlock(&info->lock);
+}
+
+static void lf_copy_from(struct map_info *map, void *to,
+                unsigned long from, ssize_t len)
+{
+        struct latch_addr_flash_info *info =
+                (struct latch_addr_flash_info *) map->map_priv_1;
+        unsigned n;
+
+        while (len > 0) {
+                n = info->win_mask + 1 - (from & info->win_mask);
+                if (n > len)
+                        n = len;
+
+                spin_lock(&info->lock);
+
+                info->set_window(from, info->data);
+                memcpy_fromio(to, map->virt + (from & info->win_mask), n);
+
+                spin_unlock(&info->lock);
+
+                to += n;
+                from += n;
+                len -= n;
+        }
+}
+
+static char *rom_probe_types[] = { "cfi_probe", NULL };
+
+static char *part_probe_types[] = { "cmdlinepart", NULL };
+
+static int latch_addr_flash_remove(struct platform_device *dev)
+{
+        struct latch_addr_flash_info *info;
+        struct latch_addr_flash_data *latch_addr_data;
+
+        info = platform_get_drvdata(dev);
+        if (info == NULL)
+                return 0;
+        platform_set_drvdata(dev, NULL);
+
+        latch_addr_data = dev->dev.platform_data;
+
+        if (info->mtd != NULL) {
+                if (mtd_has_partitions()) {
+                        if (info->nr_parts) {
+                                del_mtd_partitions(info->mtd);
+                                kfree(info->parts);
+                        } else if (latch_addr_data->nr_parts) {
+                                del_mtd_partitions(info->mtd);
+                        } else {
+                                del_mtd_device(info->mtd);
+                        }
+                } else {
+                        del_mtd_device(info->mtd);
+                }
+                map_destroy(info->mtd);
+        }
+
+        if (info->map.virt != NULL)
+                iounmap(info->map.virt);
+
+        if (info->res != NULL)
+                release_mem_region(info->res->start, resource_size(info->res));
+
+        kfree(info);
+
+        if (latch_addr_data->done)
+                latch_addr_data->done(latch_addr_data->data);
+
+        return 0;
+}
+
+static int __devinit latch_addr_flash_probe(struct platform_device *dev)
+{
+        struct latch_addr_flash_data *latch_addr_data;
+        struct latch_addr_flash_info *info;
+        resource_size_t win_base = dev->resource->start;
+        resource_size_t win_size = resource_size(dev->resource);
+        char **probe_type;
+        int chipsel;
+        int err;
+
+        latch_addr_data = dev->dev.platform_data;
+        if (latch_addr_data == NULL)
+                return -ENODEV;
+
+        pr_notice("latch-addr platform flash device: %#llx byte "
+                  "window at %#.8llx\n",
+                  (unsigned long long)win_size, (unsigned long long)win_base);
+
+        chipsel = dev->id;
+
+        if (latch_addr_data->init) {
+                err = latch_addr_data->init(latch_addr_data->data, chipsel);
+                if (err != 0)
+                        return err;
+        }
+
+        info = kzalloc(sizeof(struct latch_addr_flash_info), GFP_KERNEL);
+        if (info == NULL) {
+                err = -ENOMEM;
+                goto done;
+        }
+
+        platform_set_drvdata(dev, info);
+
+        info->res = request_mem_region(win_base, win_size, DRIVER_NAME);
+        if (info->res == NULL) {
+                dev_err(&dev->dev, "Could not reserve memory region\n");
+                err = -EBUSY;
+                goto free_info;
+        }
+
+        info->map.name          = DRIVER_NAME;
+        info->map.size          = latch_addr_data->size;
+        info->map.bankwidth     = latch_addr_data->width;
+
+        info->map.phys          = NO_XIP;
+        info->map.virt          = ioremap(win_base, win_size);
+        if (!info->map.virt) {
+                err = -ENOMEM;
+                goto free_res;
+        }
+
+        info->map.map_priv_1    = (unsigned long)info;
+
+        info->map.read          = lf_read;
+        info->map.copy_from     = lf_copy_from;
+        info->map.write         = lf_write;
+        info->set_window        = latch_addr_data->set_window;
+        info->data              = latch_addr_data->data;
+        info->win_mask          = win_size - 1;
+
+        spin_lock_init(&info->lock);
+
+        for (probe_type = rom_probe_types; !info->mtd && *probe_type;
+                probe_type++)
+                info->mtd = do_map_probe(*probe_type, &info->map);
+
+        if (info->mtd == NULL) {
+                dev_err(&dev->dev, "map_probe failed\n");
+                err = -ENODEV;
+                goto iounmap;
+        }
+        info->mtd->owner = THIS_MODULE;
+
+        if (mtd_has_partitions()) {
+
+                err = parse_mtd_partitions(info->mtd,
+                                           (const char **)part_probe_types,
+                                           &info->parts, 0);
+                if (err > 0) {
+                        add_mtd_partitions(info->mtd, info->parts, err);
+                        return 0;
+                }
+                if (latch_addr_data->nr_parts) {
+                        pr_notice("Using latch-addr-flash partition information\n");
+                        add_mtd_partitions(info->mtd, latch_addr_data->parts,
+                                        latch_addr_data->nr_parts);
+                        return 0;
+                }
+        }
+        add_mtd_device(info->mtd);
+        return 0;
+
+iounmap:
+        iounmap(info->map.virt);
+free_res:
+        release_mem_region(info->res->start, resource_size(info->res));
+free_info:
+        kfree(info);
+done:
+        if (latch_addr_data->done)
+                latch_addr_data->done(latch_addr_data->data);
+        return err;
+}
+
+static struct platform_driver latch_addr_flash_driver = {
+        .probe          = latch_addr_flash_probe,
+        .remove         = __devexit_p(latch_addr_flash_remove),
+        .driver         = {
+                .name   = DRIVER_NAME,
+        },
+};
+
+static int __init latch_addr_flash_init(void)
+{
+        return platform_driver_register(&latch_addr_flash_driver);
+}
+module_init(latch_addr_flash_init);
+
+static void __exit latch_addr_flash_exit(void)
+{
+        platform_driver_unregister(&latch_addr_flash_driver);
+}
+module_exit(latch_addr_flash_exit);
+
+MODULE_AUTHOR("David Griego <dgriego@mvista.com>");
+MODULE_DESCRIPTION("MTD map driver for flashes addressed physically with upper "
+                "address lines being set board specifically");
+MODULE_LICENSE("GPL v2");