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>

4 files changed, 116 insertions, 0 deletions

diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig
index 6cc5a1ac3802..27f80cd8aef3 100644
--- a/drivers/mtd/devices/Kconfig
+++ b/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
diff --git a/drivers/mtd/devices/Makefile b/drivers/mtd/devices/Makefile
index a4dd1d822b6c..395733a30ef4 100644
--- a/drivers/mtd/devices/Makefile
+++ b/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
diff --git a/drivers/mtd/devices/bcm47xxsflash.c b/drivers/mtd/devices/bcm47xxsflash.c
new file mode 100644
index 000000000000..2dc5a6f3fd57
--- /dev/null
+++ b/drivers/mtd/devices/bcm47xxsflash.c
@@ -0,0 +1,105 @@
+#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);
diff --git a/include/linux/bcma/bcma_driver_chipcommon.h b/include/linux/bcma/bcma_driver_chipcommon.h
index 6ba45d2b99db..1cf1749440ac 100644
--- a/include/linux/bcma/bcma_driver_chipcommon.h
+++ b/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