mtd: basic (read only) driver for BCMA serial flash

This registers MTD driver for serial flash platform device. Right now it
supports reading only, writing still has to be implemented.

Artem: minor amendments.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

drivers/mtd/devices/Kconfig

@@ -120,6 +120,14 @@ config MTD_SST25L
 	  Set up your spi devices with the right board-specific platform data,
 	  if you want to specify device partitioning.
 
+config MTD_BCM47XXSFLASH
+	tristate "R/O support for serial flash on BCMA bus"
+	depends on BCMA_SFLASH
+	help
+	  BCMA bus can have various flash memories attached, they are
+	  registered by bcma as platform devices. This enables driver for
+	  serial flash memories (only read-only mode is implemented).
+
 config MTD_SLRAM
 	tristate "Uncached system RAM"
 	help

drivers/mtd/devices/Makefile

@@ -19,5 +19,6 @@ obj-$(CONFIG_MTD_DATAFLASH)	+= mtd_dataflash.o
 obj-$(CONFIG_MTD_M25P80)	+= m25p80.o
 obj-$(CONFIG_MTD_SPEAR_SMI)	+= spear_smi.o
 obj-$(CONFIG_MTD_SST25L)	+= sst25l.o
+obj-$(CONFIG_MTD_BCM47XXSFLASH)	+= bcm47xxsflash.o
 
 CFLAGS_docg3.o			+= -I$(src)
\ No newline at end of file

drivers/mtd/devices/bcm47xxsflash.c

+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+#include <linux/platform_device.h>
+#include <linux/bcma/bcma.h>
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("Serial flash driver for BCMA bus");
+
+static const char *probes[] = { "bcm47xxpart", NULL };
+
+static int bcm47xxsflash_read(struct mtd_info *mtd, loff_t from, size_t len,
+			      size_t *retlen, u_char *buf)
+{
+	struct bcma_sflash *sflash = mtd->priv;
+
+	/* Check address range */
+	if ((from + len) > mtd->size)
+		return -EINVAL;
+
+	memcpy_fromio(buf, (void __iomem *)KSEG0ADDR(sflash->window + from),
+		      len);
+
+	return len;
+}
+
+static void bcm47xxsflash_fill_mtd(struct bcma_sflash *sflash,
+				   struct mtd_info *mtd)
+{
+	mtd->priv = sflash;
+	mtd->name = "bcm47xxsflash";
+	mtd->owner = THIS_MODULE;
+	mtd->type = MTD_ROM;
+	mtd->size = sflash->size;
+	mtd->_read = bcm47xxsflash_read;
+
+	/* TODO: implement writing support and verify/change following code */
+	mtd->flags = MTD_CAP_ROM;
+	mtd->writebufsize = mtd->writesize = 1;
+}
+
+static int bcm47xxsflash_probe(struct platform_device *pdev)
+{
+	struct bcma_sflash *sflash = dev_get_platdata(&pdev->dev);
+	int err;
+
+	sflash->mtd = kzalloc(sizeof(struct mtd_info), GFP_KERNEL);
+	if (!sflash->mtd) {
+		err = -ENOMEM;
+		goto out;
+	}
+	bcm47xxsflash_fill_mtd(sflash, sflash->mtd);
+
+	err = mtd_device_parse_register(sflash->mtd, probes, NULL, NULL, 0);
+	if (err) {
+		pr_err("Failed to register MTD device: %d\n", err);
+		goto err_dev_reg;
+	}
+
+	return 0;
+
+err_dev_reg:
+	kfree(sflash->mtd);
+out:
+	return err;
+}
+
+static int __devexit bcm47xxsflash_remove(struct platform_device *pdev)
+{
+	struct bcma_sflash *sflash = dev_get_platdata(&pdev->dev);
+
+	mtd_device_unregister(sflash->mtd);
+	kfree(sflash->mtd);
+
+	return 0;
+}
+
+static struct platform_driver bcma_sflash_driver = {
+	.remove = __devexit_p(bcm47xxsflash_remove),
+	.driver = {
+		.name = "bcma_sflash",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init bcm47xxsflash_init(void)
+{
+	int err;
+
+	err = platform_driver_probe(&bcma_sflash_driver, bcm47xxsflash_probe);
+	if (err)
+		pr_err("Failed to register BCMA serial flash driver: %d\n",
+		       err);
+
+	return err;
+}
+
+static void __exit bcm47xxsflash_exit(void)
+{
+	platform_driver_unregister(&bcma_sflash_driver);
+}
+
+module_init(bcm47xxsflash_init);
+module_exit(bcm47xxsflash_exit);

include/linux/bcma/bcma_driver_chipcommon.h

@@ -522,6 +522,8 @@ struct bcma_sflash {
 	u32 blocksize;
 	u16 numblocks;
 	u32 size;
+
+	struct mtd_info *mtd;
 };
 #endif