mtd: Really add ARM pismo support

(Commit 7cb777a3d7 (mtd: add ARM pismo support)
intended to add this, but seems only to have patched the Makefile without
touching Kconfig or providing any code...)

The following patch adds support for PISMO modules found on ARM Ltd
development platforms.  These are MTD modules, and can have a
selection of SRAM, flash or DOC devices as described by an on-board
I2C EEPROM.

We support SRAM and NOR flash devices only by registering appropriate
conventional MTD platform devices as children of the 'pismo' device.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/maps/Kconfig

@@ -549,4 +549,21 @@ config MTD_VMU
 	  To build this as a module select M here, the module will be called
 	  vmu-flash.
 
+config MTD_PISMO
+	tristate "MTD discovery driver for PISMO modules"
+	depends on I2C
+	depends on ARCH_VERSATILE
+	help
+	  This driver allows for discovery of PISMO modules - see
+	  <http://www.pismoworld.org/>.  These are small modules containing
+	  up to five memory devices (eg, SRAM, flash, DOC) described by an
+	  I2C EEPROM.
+
+	  This driver does not create any MTD maps itself; instead it
+	  creates MTD physmap and MTD SRAM platform devices.  If you
+	  enable this option, you should consider enabling MTD_PHYSMAP
+	  and/or MTD_PLATRAM according to the devices on your module.
+
+	  When built as a module, it will be called pismo.ko
+
 endmenu

drivers/mtd/maps/pismo.c

@@ -0,0 +1,320 @@
+/*
+ * PISMO memory driver - http://www.pismoworld.org/
+ *
+ * For ARM Realview and Versatile platforms
+ *
+ * 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.
+ */
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/mtd/physmap.h>
+#include <linux/mtd/plat-ram.h>
+#include <linux/mtd/pismo.h>
+
+#define PISMO_NUM_CS	5
+
+struct pismo_cs_block {
+	u8	type;
+	u8	width;
+	__le16	access;
+	__le32	size;
+	u32	reserved[2];
+	char	device[32];
+} __packed;
+
+struct pismo_eeprom {
+	struct pismo_cs_block cs[PISMO_NUM_CS];
+	char	board[15];
+	u8	sum;
+} __packed;
+
+struct pismo_mem {
+	phys_addr_t base;
+	u32	size;
+	u16	access;
+	u8	width;
+	u8	type;
+};
+
+struct pismo_data {
+	struct i2c_client	*client;
+	void			(*vpp)(void *, int);
+	void			*vpp_data;
+	struct platform_device	*dev[PISMO_NUM_CS];
+};
+
+/* FIXME: set_vpp could do with a better calling convention */
+static struct pismo_data *vpp_pismo;
+static DEFINE_MUTEX(pismo_mutex);
+
+static int pismo_setvpp_probe_fix(struct pismo_data *pismo)
+{
+	mutex_lock(&pismo_mutex);
+	if (vpp_pismo) {
+		mutex_unlock(&pismo_mutex);
+		kfree(pismo);
+		return -EBUSY;
+	}
+	vpp_pismo = pismo;
+	mutex_unlock(&pismo_mutex);
+	return 0;
+}
+
+static void pismo_setvpp_remove_fix(struct pismo_data *pismo)
+{
+	mutex_lock(&pismo_mutex);
+	if (vpp_pismo == pismo)
+		vpp_pismo = NULL;
+	mutex_unlock(&pismo_mutex);
+}
+
+static void pismo_set_vpp(struct map_info *map, int on)
+{
+	struct pismo_data *pismo = vpp_pismo;
+
+	pismo->vpp(pismo->vpp_data, on);
+}
+/* end of hack */
+
+
+static unsigned int __devinit pismo_width_to_bytes(unsigned int width)
+{
+	width &= 15;
+	if (width > 2)
+		return 0;
+	return 1 << width;
+}
+
+static int __devinit pismo_eeprom_read(struct i2c_client *client, void *buf,
+	u8 addr, size_t size)
+{
+	int ret;
+	struct i2c_msg msg[] = {
+		{
+			.addr = client->addr,
+			.len = sizeof(addr),
+			.buf = &addr,
+		}, {
+			.addr = client->addr,
+			.flags = I2C_M_RD,
+			.len = size,
+			.buf = buf,
+		},
+	};
+
+	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+
+	return ret == ARRAY_SIZE(msg) ? size : -EIO;
+}
+
+static int __devinit pismo_add_device(struct pismo_data *pismo, int i,
+	struct pismo_mem *region, const char *name, void *pdata, size_t psize)
+{
+	struct platform_device *dev;
+	struct resource res = { };
+	phys_addr_t base = region.base;
+	int ret;
+
+	if (base == ~0)
+		return -ENXIO;
+
+	res.start = base;
+	res.end = base + region->size - 1;
+	res.flags = IORESOURCE_MEM;
+
+	dev = platform_device_alloc(name, i);
+	if (!dev)
+		return -ENOMEM;
+	dev->dev.parent = &pismo->client->dev;
+
+	do {
+		ret = platform_device_add_resources(dev, &res, 1);
+		if (ret)
+			break;
+
+		ret = platform_device_add_data(dev, pdata, psize);
+		if (ret)
+			break;
+
+		ret = platform_device_add(dev);
+		if (ret)
+			break;
+
+		pismo->dev[i] = dev;
+		return 0;
+	} while (0);
+
+	platform_device_put(dev);
+	return ret;
+}
+
+static int __devinit pismo_add_nor(struct pismo_data *pismo, int i,
+	struct pismo_mem *region)
+{
+	struct physmap_flash_data data = {
+		.width = region->width,
+	};
+
+	if (pismo->vpp)
+		data.set_vpp = pismo_set_vpp;
+
+	return pismo_add_device(pismo, i, region, "physmap-flash",
+		&data, sizeof(data));
+}
+
+static int __devinit pismo_add_sram(struct pismo_data *pismo, int i,
+	struct pismo_mem *region)
+{
+	struct platdata_mtd_ram data = {
+		.bankwidth = region->width,
+	};
+
+	return pismo_add_device(pismo, i, region, "mtd-ram",
+		&data, sizeof(data));
+}
+
+static void __devinit pismo_add_one(struct pismo_data *pismo, int i,
+	const struct pismo_cs_block *cs, phys_addr_t base)
+{
+	struct device *dev = &pismo->client->dev;
+	struct pismo_mem region;
+
+	region.base = base;
+	region.type = cs->type;
+	region.width = pismo_width_to_bytes(cs->width);
+	region.access = le16_to_cpu(cs->access);
+	region.size = le32_to_cpu(cs->size);
+
+	if (region.width == 0) {
+		dev_err(dev, "cs%u: bad width: %02x, ignoring\n", i, cs->width);
+		return;
+	}
+
+	/*
+	 * FIXME: may need to the platforms memory controller here, but at
+	 * the moment we assume that it has already been correctly setup.
+	 * The memory controller can also tell us the base address as well.
+	 */
+
+	dev_info(dev, "cs%u: %.32s: type %02x access %u00ps size %uK\n",
+		i, cs->device, region.type, region.access, region.size / 1024);
+
+	switch (region.type) {
+	case 0:
+		break;
+	case 1:
+		/* static DOC */
+		break;
+	case 2:
+		/* static NOR */
+		pismo_add_nor(pismo, i, &region);
+		break;
+	case 3:
+		/* static RAM */
+		pismo_add_sram(pismo, i, &region);
+		break;
+	}
+}
+
+static int __devexit pismo_remove(struct i2c_client *client)
+{
+	struct pismo_data *pismo = i2c_get_clientdata(client);
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(pismo->dev); i++)
+		platform_device_unregister(pismo->dev[i]);
+
+	/* FIXME: set_vpp needs saner arguments */
+	pismo_setvpp_remove_fix(pismo);
+
+	kfree(pismo);
+
+	return 0;
+}
+
+static int __devinit pismo_probe(struct i2c_client *client,
+				 const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+	struct pismo_pdata *pdata = client->dev.platform_data;
+	struct pismo_eeprom eeprom;
+	struct pismo_data *pismo;
+	int ret, i;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_I2C)) {
+		dev_err(&client->dev, "functionality mismatch\n");
+		return -EIO;
+	}
+
+	pismo = kzalloc(sizeof(*pismo), GFP_KERNEL);
+	if (!pismo)
+		return -ENOMEM;
+
+	/* FIXME: set_vpp needs saner arguments */
+	ret = pismo_setvpp_probe_fix(pismo);
+	if (ret)
+		return ret;
+
+	pismo->client = client;
+	if (pdata) {
+		pismo->vpp = pdata->set_vpp;
+		pismo->vpp_data = pdata->vpp_data;
+	}
+	i2c_set_clientdata(client, pismo);
+
+	ret = pismo_eeprom_read(client, &eeprom, 0, sizeof(eeprom));
+	if (ret < 0) {
+		dev_err(&client->dev, "error reading EEPROM: %d\n", ret);
+		return ret;
+	}
+
+	dev_info(&client->dev, "%.15s board found\n", eeprom.board);
+
+	for (i = 0; i < ARRAY_SIZE(eeprom.cs); i++)
+		if (eeprom.cs[i].type != 0xff)
+			pismo_add_one(pismo, i, &eeprom.cs[i],
+				      pdata->cs_addrs[i]);
+
+	return 0;
+}
+
+static const struct i2c_device_id pismo_id[] = {
+	{ "pismo" },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, pismo_id);
+
+static struct i2c_driver pismo_driver = {
+	.driver	= {
+		.name	= "pismo",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= pismo_probe,
+	.remove		= __devexit_p(pismo_remove),
+	.id_table	= pismo_id,
+};
+
+static int __init pismo_init(void)
+{
+	BUILD_BUG_ON(sizeof(struct pismo_cs_block) != 48);
+	BUILD_BUG_ON(sizeof(struct pismo_eeprom) != 256);
+
+	return i2c_add_driver(&pismo_driver);
+}
+module_init(pismo_init);
+
+static void __exit pismo_exit(void)
+{
+	i2c_del_driver(&pismo_driver);
+}
+module_exit(pismo_exit);
+
+MODULE_AUTHOR("Russell King <linux@arm.linux.org.uk>");
+MODULE_DESCRIPTION("PISMO memory driver");
+MODULE_LICENSE("GPL");

include/linux/mtd/pismo.h

@@ -0,0 +1,17 @@
+/*
+ * PISMO memory driver - http://www.pismoworld.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.
+ */
+#ifndef __LINUX_MTD_PISMO_H
+#define __LINUX_MTD_PISMO_H
+
+struct pismo_pdata {
+	void			(*set_vpp)(void *, int);
+	void			*vpp_data;
+	phys_addr_t		cs_addrs[5];
+};
+
+#endif