mmc: Driver for CB710/720 memory card reader (MMC part)

The code is divided in two parts. There is a virtual 'bus' driver
that handles PCI device and registers three new devices one per card
reader type. The other driver handles SD/MMC part of the reader.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Signed-off-by: Pierre Ossman <pierre@ossman.eu>

5 files changed, 651 insertions, 0 deletions

diff --git a/drivers/misc/cb710/Kconfig b/drivers/misc/cb710/Kconfig
new file mode 100644
index 00000000000..0b55079774c
--- /dev/null
+++ b/drivers/misc/cb710/Kconfig
@@ -0,0 +1,21 @@
+config CB710_CORE
+        tristate "ENE CB710/720 Flash memory card reader support"
+        depends on PCI
+        help
+          This option enables support for PCI ENE CB710/720 Flash memory card
+          reader found in some laptops (ie. some versions of HP Compaq nx9500).
+
+          You will also have to select some flash card format drivers (MMC/SD,
+          MemoryStick).
+
+          This driver can also be built as a module. If so, the module
+          will be called cb710.
+
+config CB710_DEBUG
+        bool "Enable driver debugging"
+        depends on CB710_CORE != n
+        default n
+        help
+          This is an option for use by developers; most people should
+          say N here.  This adds a lot of debugging output to dmesg.
+
diff --git a/drivers/misc/cb710/Makefile b/drivers/misc/cb710/Makefile
new file mode 100644
index 00000000000..62d51acfeca
--- /dev/null
+++ b/drivers/misc/cb710/Makefile
@@ -0,0 +1,4 @@
+obj-$(CONFIG_CB710_CORE)        += cb710.o
+
+cb710-y                         := core.o sgbuf2.o
+cb710-$(CONFIG_CB710_DEBUG)     += debug.o
diff --git a/drivers/misc/cb710/core.c b/drivers/misc/cb710/core.c
new file mode 100644
index 00000000000..b14eab0f2ba
--- /dev/null
+++ b/drivers/misc/cb710/core.c
@@ -0,0 +1,357 @@
+/*
+ *  cb710/core.c
+ *
+ *  Copyright by Michał Mirosław, 2008-2009
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+#include <linux/idr.h>
+#include <linux/cb710.h>
+
+static DEFINE_IDA(cb710_ida);
+static DEFINE_SPINLOCK(cb710_ida_lock);
+
+void cb710_pci_update_config_reg(struct pci_dev *pdev,
+        int reg, uint32_t mask, uint32_t xor)
+{
+        u32 rval;
+
+        pci_read_config_dword(pdev, reg, &rval);
+        rval = (rval & mask) ^ xor;
+        pci_write_config_dword(pdev, reg, rval);
+}
+EXPORT_SYMBOL_GPL(cb710_pci_update_config_reg);
+
+/* Some magic writes based on Windows driver init code */
+static int __devinit cb710_pci_configure(struct pci_dev *pdev)
+{
+        unsigned int devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0);
+        struct pci_dev *pdev0 = pci_get_slot(pdev->bus, devfn);
+        u32 val;
+
+        cb710_pci_update_config_reg(pdev, 0x48,
+                ~0x000000FF, 0x0000003F);
+
+        pci_read_config_dword(pdev, 0x48, &val);
+        if (val & 0x80000000)
+                return 0;
+
+        if (!pdev0)
+                return -ENODEV;
+
+        if (pdev0->vendor == PCI_VENDOR_ID_ENE
+            && pdev0->device == PCI_DEVICE_ID_ENE_720) {
+                cb710_pci_update_config_reg(pdev0, 0x8C,
+                        ~0x00F00000, 0x00100000);
+                cb710_pci_update_config_reg(pdev0, 0xB0,
+                        ~0x08000000, 0x08000000);
+        }
+
+        cb710_pci_update_config_reg(pdev0, 0x8C,
+                ~0x00000F00, 0x00000200);
+        cb710_pci_update_config_reg(pdev0, 0x90,
+                ~0x00060000, 0x00040000);
+
+        pci_dev_put(pdev0);
+
+        return 0;
+}
+
+static irqreturn_t cb710_irq_handler(int irq, void *data)
+{
+        struct cb710_chip *chip = data;
+        struct cb710_slot *slot = &chip->slot[0];
+        irqreturn_t handled = IRQ_NONE;
+        unsigned nr;
+
+        spin_lock(&chip->irq_lock); /* incl. smp_rmb() */
+
+        for (nr = chip->slots; nr; ++slot, --nr) {
+                cb710_irq_handler_t handler_func = slot->irq_handler;
+                if (handler_func && handler_func(slot))
+                        handled = IRQ_HANDLED;
+        }
+
+        spin_unlock(&chip->irq_lock);
+
+        return handled;
+}
+
+static void cb710_release_slot(struct device *dev)
+{
+#ifdef CONFIG_CB710_DEBUG_ASSUMPTIONS
+        struct cb710_slot *slot = cb710_pdev_to_slot(to_platform_device(dev));
+        struct cb710_chip *chip = cb710_slot_to_chip(slot);
+
+        /* slot struct can be freed now */
+        atomic_dec(&chip->slot_refs_count);
+#endif
+}
+
+static int __devinit cb710_register_slot(struct cb710_chip *chip,
+        unsigned slot_mask, unsigned io_offset, const char *name)
+{
+        int nr = chip->slots;
+        struct cb710_slot *slot = &chip->slot[nr];
+        int err;
+
+        dev_dbg(cb710_chip_dev(chip),
+                "register: %s.%d; slot %d; mask %d; IO offset: 0x%02X\n",
+                name, chip->platform_id, nr, slot_mask, io_offset);
+
+        /* slot->irq_handler == NULL here; this needs to be
+         * seen before platform_device_register() */
+        ++chip->slots;
+        smp_wmb();
+
+        slot->iobase = chip->iobase + io_offset;
+        slot->pdev.name = name;
+        slot->pdev.id = chip->platform_id;
+        slot->pdev.dev.parent = &chip->pdev->dev;
+        slot->pdev.dev.release = cb710_release_slot;
+
+        err = platform_device_register(&slot->pdev);
+
+#ifdef CONFIG_CB710_DEBUG_ASSUMPTIONS
+        atomic_inc(&chip->slot_refs_count);
+#endif
+
+        if (err) {
+                /* device_initialize() called from platform_device_register()
+                 * wants this on error path */
+                platform_device_put(&slot->pdev);
+
+                /* slot->irq_handler == NULL here anyway, so no lock needed */
+                --chip->slots;
+                return err;
+        }
+
+        chip->slot_mask |= slot_mask;
+
+        return 0;
+}
+
+static void cb710_unregister_slot(struct cb710_chip *chip,
+        unsigned slot_mask)
+{
+        int nr = chip->slots - 1;
+
+        if (!(chip->slot_mask & slot_mask))
+                return;
+
+        platform_device_unregister(&chip->slot[nr].pdev);
+
+        /* complementary to spin_unlock() in cb710_set_irq_handler() */
+        smp_rmb();
+        BUG_ON(chip->slot[nr].irq_handler != NULL);
+
+        /* slot->irq_handler == NULL here, so no lock needed */
+        --chip->slots;
+        chip->slot_mask &= ~slot_mask;
+}
+
+void cb710_set_irq_handler(struct cb710_slot *slot,
+        cb710_irq_handler_t handler)
+{
+        struct cb710_chip *chip = cb710_slot_to_chip(slot);
+        unsigned long flags;
+
+        spin_lock_irqsave(&chip->irq_lock, flags);
+        slot->irq_handler = handler;
+        spin_unlock_irqrestore(&chip->irq_lock, flags);
+}
+EXPORT_SYMBOL_GPL(cb710_set_irq_handler);
+
+#ifdef CONFIG_PM
+
+static int cb710_suspend(struct pci_dev *pdev, pm_message_t state)
+{
+        struct cb710_chip *chip = pci_get_drvdata(pdev);
+
+        free_irq(pdev->irq, chip);
+        pci_save_state(pdev);
+        pci_disable_device(pdev);
+        if (state.event & PM_EVENT_SLEEP)
+                pci_set_power_state(pdev, PCI_D3cold);
+        return 0;
+}
+
+static int cb710_resume(struct pci_dev *pdev)
+{
+        struct cb710_chip *chip = pci_get_drvdata(pdev);
+        int err;
+
+        pci_set_power_state(pdev, PCI_D0);
+        pci_restore_state(pdev);
+        err = pcim_enable_device(pdev);
+        if (err)
+                return err;
+
+        return devm_request_irq(&pdev->dev, pdev->irq,
+                cb710_irq_handler, IRQF_SHARED, KBUILD_MODNAME, chip);
+}
+
+#endif /* CONFIG_PM */
+
+static int __devinit cb710_probe(struct pci_dev *pdev,
+        const struct pci_device_id *ent)
+{
+        struct cb710_chip *chip;
+        unsigned long flags;
+        u32 val;
+        int err;
+        int n = 0;
+
+        err = cb710_pci_configure(pdev);
+        if (err)
+                return err;
+
+        /* this is actually magic... */
+        pci_read_config_dword(pdev, 0x48, &val);
+        if (!(val & 0x80000000)) {
+                pci_write_config_dword(pdev, 0x48, val|0x71000000);
+                pci_read_config_dword(pdev, 0x48, &val);
+        }
+
+        dev_dbg(&pdev->dev, "PCI config[0x48] = 0x%08X\n", val);
+        if (!(val & 0x70000000))
+                return -ENODEV;
+        val = (val >> 28) & 7;
+        if (val & CB710_SLOT_MMC)
+                ++n;
+        if (val & CB710_SLOT_MS)
+                ++n;
+        if (val & CB710_SLOT_SM)
+                ++n;
+
+        chip = devm_kzalloc(&pdev->dev,
+                sizeof(*chip) + n * sizeof(*chip->slot), GFP_KERNEL);
+        if (!chip)
+                return -ENOMEM;
+
+        err = pcim_enable_device(pdev);
+        if (err)
+                return err;
+
+        err = pcim_iomap_regions(pdev, 0x0001, KBUILD_MODNAME);
+        if (err)
+                return err;
+
+        chip->pdev = pdev;
+        chip->iobase = pcim_iomap_table(pdev)[0];
+
+        pci_set_drvdata(pdev, chip);
+
+        err = devm_request_irq(&pdev->dev, pdev->irq,
+                cb710_irq_handler, IRQF_SHARED, KBUILD_MODNAME, chip);
+        if (err)
+                return err;
+
+        do {
+                if (!ida_pre_get(&cb710_ida, GFP_KERNEL))
+                        return -ENOMEM;
+
+                spin_lock_irqsave(&cb710_ida_lock, flags);
+                err = ida_get_new(&cb710_ida, &chip->platform_id);
+                spin_unlock_irqrestore(&cb710_ida_lock, flags);
+
+                if (err && err != -EAGAIN)
+                        return err;
+        } while (err);
+
+
+        dev_info(&pdev->dev, "id %d, IO 0x%p, IRQ %d\n",
+                chip->platform_id, chip->iobase, pdev->irq);
+
+        if (val & CB710_SLOT_MMC) {     /* MMC/SD slot */
+                err = cb710_register_slot(chip,
+                        CB710_SLOT_MMC, 0x00, "cb710-mmc");
+                if (err)
+                        return err;
+        }
+
+        if (val & CB710_SLOT_MS) {      /* MemoryStick slot */
+                err = cb710_register_slot(chip,
+                        CB710_SLOT_MS, 0x40, "cb710-ms");
+                if (err)
+                        goto unreg_mmc;
+        }
+
+        if (val & CB710_SLOT_SM) {      /* SmartMedia slot */
+                err = cb710_register_slot(chip,
+                        CB710_SLOT_SM, 0x60, "cb710-sm");
+                if (err)
+                        goto unreg_ms;
+        }
+
+        return 0;
+unreg_ms:
+        cb710_unregister_slot(chip, CB710_SLOT_MS);
+unreg_mmc:
+        cb710_unregister_slot(chip, CB710_SLOT_MMC);
+
+#ifdef CONFIG_CB710_DEBUG_ASSUMPTIONS
+        BUG_ON(atomic_read(&chip->slot_refs_count) != 0);
+#endif
+        return err;
+}
+
+static void __devexit cb710_remove_one(struct pci_dev *pdev)
+{
+        struct cb710_chip *chip = pci_get_drvdata(pdev);
+        unsigned long flags;
+
+        cb710_unregister_slot(chip, CB710_SLOT_SM);
+        cb710_unregister_slot(chip, CB710_SLOT_MS);
+        cb710_unregister_slot(chip, CB710_SLOT_MMC);
+#ifdef CONFIG_CB710_DEBUG_ASSUMPTIONS
+        BUG_ON(atomic_read(&chip->slot_refs_count) != 0);
+#endif
+
+        spin_lock_irqsave(&cb710_ida_lock, flags);
+        ida_remove(&cb710_ida, chip->platform_id);
+        spin_unlock_irqrestore(&cb710_ida_lock, flags);
+}
+
+static const struct pci_device_id cb710_pci_tbl[] = {
+        { PCI_VENDOR_ID_ENE, PCI_DEVICE_ID_ENE_CB710_FLASH,
+                PCI_ANY_ID, PCI_ANY_ID, },
+        { 0, }
+};
+
+static struct pci_driver cb710_driver = {
+        .name = KBUILD_MODNAME,
+        .id_table = cb710_pci_tbl,
+        .probe = cb710_probe,
+        .remove = __devexit_p(cb710_remove_one),
+#ifdef CONFIG_PM
+        .suspend = cb710_suspend,
+        .resume = cb710_resume,
+#endif
+};
+
+static int __init cb710_init_module(void)
+{
+        return pci_register_driver(&cb710_driver);
+}
+
+static void __exit cb710_cleanup_module(void)
+{
+        pci_unregister_driver(&cb710_driver);
+        ida_destroy(&cb710_ida);
+}
+
+module_init(cb710_init_module);
+module_exit(cb710_cleanup_module);
+
+MODULE_AUTHOR("Michał Mirosław <mirq-linux@rere.qmqm.pl>");
+MODULE_DESCRIPTION("ENE CB710 memory card reader driver");
+MODULE_LICENSE("GPL");
+MODULE_DEVICE_TABLE(pci, cb710_pci_tbl);
diff --git a/drivers/misc/cb710/debug.c b/drivers/misc/cb710/debug.c
new file mode 100644
index 00000000000..9da11bc620a
--- /dev/null
+++ b/drivers/misc/cb710/debug.c
@@ -0,0 +1,119 @@
+/*
+ *  cb710/debug.c
+ *
+ *  Copyright by Michał Mirosław, 2008-2009
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/cb710.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+
+#define CB710_REG_COUNT         0x80
+
+static const u16 allow[CB710_REG_COUNT/16] = {
+        0xFFF0, 0xFFFF, 0xFFFF, 0xFFFF,
+        0xFFF0, 0xFFFF, 0xFFFF, 0xFFFF,
+};
+static const char *const prefix[ARRAY_SIZE(allow)] = {
+        "MMC", "MMC", "MMC", "MMC",
+        "MS?", "MS?", "SM?", "SM?"
+};
+
+static inline int allow_reg_read(unsigned block, unsigned offset, unsigned bits)
+{
+        unsigned mask = (1 << bits/8) - 1;
+        offset *= bits/8;
+        return ((allow[block] >> offset) & mask) == mask;
+}
+
+#define CB710_READ_REGS_TEMPLATE(t)                                     \
+static void cb710_read_regs_##t(void __iomem *iobase,                   \
+        u##t *reg, unsigned select)                                     \
+{                                                                       \
+        unsigned i, j;                                                  \
+                                                                        \
+        for (i = 0; i < ARRAY_SIZE(allow); ++i, reg += 16/(t/8)) {      \
+                if (!select & (1 << i))                                 \
+                        continue;                                       \
+                                                                        \
+                for (j = 0; j < 0x10/(t/8); ++j) {                      \
+                        if (!allow_reg_read(i, j, t))                   \
+                                continue;                               \
+                        reg[j] = ioread##t(iobase                       \
+                                + (i << 4) + (j * (t/8)));              \
+                }                                                       \
+        }                                                               \
+}
+
+static const char cb710_regf_8[] = "%02X";
+static const char cb710_regf_16[] = "%04X";
+static const char cb710_regf_32[] = "%08X";
+static const char cb710_xes[] = "xxxxxxxx";
+
+#define CB710_DUMP_REGS_TEMPLATE(t)                                     \
+static void cb710_dump_regs_##t(struct device *dev,                     \
+        const u##t *reg, unsigned select)                               \
+{                                                                       \
+        const char *const xp = &cb710_xes[8 - t/4];                     \
+        const char *const format = cb710_regf_##t;                      \
+                                                                        \
+        char msg[100], *p;                                              \
+        unsigned i, j;                                                  \
+                                                                        \
+        for (i = 0; i < ARRAY_SIZE(allow); ++i, reg += 16/(t/8)) {      \
+                if (!(select & (1 << i)))                               \
+                        continue;                                       \
+                p = msg;                                                \
+                for (j = 0; j < 0x10/(t/8); ++j) {                      \
+                        *p++ = ' ';                                     \
+                        if (j == 8/(t/8))                               \
+                                *p++ = ' ';                             \
+                        if (allow_reg_read(i, j, t))                    \
+                                p += sprintf(p, format, reg[j]);        \
+                        else                                            \
+                                p += sprintf(p, "%s", xp);              \
+                }                                                       \
+                dev_dbg(dev, "%s 0x%02X %s\n", prefix[i], i << 4, msg); \
+        }                                                               \
+}
+
+#define CB710_READ_AND_DUMP_REGS_TEMPLATE(t)                            \
+static void cb710_read_and_dump_regs_##t(struct cb710_chip *chip,       \
+        unsigned select)                                                \
+{                                                                       \
+        u##t regs[CB710_REG_COUNT/sizeof(u##t)];                        \
+                                                                        \
+        memset(&regs, 0, sizeof(regs));                                 \
+        cb710_read_regs_##t(chip->iobase, regs, select);                \
+        cb710_dump_regs_##t(cb710_chip_dev(chip), regs, select);        \
+}
+
+#define CB710_REG_ACCESS_TEMPLATES(t)           \
+  CB710_READ_REGS_TEMPLATE(t)                   \
+  CB710_DUMP_REGS_TEMPLATE(t)                   \
+  CB710_READ_AND_DUMP_REGS_TEMPLATE(t)
+
+CB710_REG_ACCESS_TEMPLATES(8)
+CB710_REG_ACCESS_TEMPLATES(16)
+CB710_REG_ACCESS_TEMPLATES(32)
+
+void cb710_dump_regs(struct cb710_chip *chip, unsigned select)
+{
+        if (!(select & CB710_DUMP_REGS_MASK))
+                select = CB710_DUMP_REGS_ALL;
+        if (!(select & CB710_DUMP_ACCESS_MASK))
+                select |= CB710_DUMP_ACCESS_8;
+
+        if (select & CB710_DUMP_ACCESS_32)
+                cb710_read_and_dump_regs_32(chip, select);
+        if (select & CB710_DUMP_ACCESS_16)
+                cb710_read_and_dump_regs_16(chip, select);
+        if (select & CB710_DUMP_ACCESS_8)
+                cb710_read_and_dump_regs_8(chip, select);
+}
+EXPORT_SYMBOL_GPL(cb710_dump_regs);
+
diff --git a/drivers/misc/cb710/sgbuf2.c b/drivers/misc/cb710/sgbuf2.c
new file mode 100644
index 00000000000..d38a7acdb6e
--- /dev/null
+++ b/drivers/misc/cb710/sgbuf2.c
@@ -0,0 +1,150 @@
+/*
+ *  cb710/sgbuf2.c
+ *
+ *  Copyright by Michał Mirosław, 2008-2009
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/cb710.h>
+
+static bool sg_dwiter_next(struct sg_mapping_iter *miter)
+{
+        if (sg_miter_next(miter)) {
+                miter->consumed = 0;
+                return true;
+        } else
+                return false;
+}
+
+static bool sg_dwiter_is_at_end(struct sg_mapping_iter *miter)
+{
+        return miter->length == miter->consumed && !sg_dwiter_next(miter);
+}
+
+static uint32_t sg_dwiter_read_buffer(struct sg_mapping_iter *miter)
+{
+        size_t len, left = 4;
+        uint32_t data;
+        void *addr = &data;
+
+        do {
+                len = min(miter->length - miter->consumed, left);
+                memcpy(addr, miter->addr + miter->consumed, len);
+                miter->consumed += len;
+                left -= len;
+                if (!left)
+                        return data;
+                addr += len;
+        } while (sg_dwiter_next(miter));
+
+        memset(addr, 0, left);
+        return data;
+}
+
+static inline bool needs_unaligned_copy(const void *ptr)
+{
+#ifdef HAVE_EFFICIENT_UNALIGNED_ACCESS
+        return false;
+#else
+        return ((ptr - NULL) & 3) != 0;
+#endif
+}
+
+static bool sg_dwiter_get_next_block(struct sg_mapping_iter *miter, uint32_t **ptr)
+{
+        size_t len;
+
+        if (sg_dwiter_is_at_end(miter))
+                return true;
+
+        len = miter->length - miter->consumed;
+
+        if (likely(len >= 4 && !needs_unaligned_copy(
+                        miter->addr + miter->consumed))) {
+                *ptr = miter->addr + miter->consumed;
+                miter->consumed += 4;
+                return true;
+        }
+
+        return false;
+}
+
+/**
+ * cb710_sg_dwiter_read_next_block() - get next 32-bit word from sg buffer
+ * @miter: sg mapping iterator used for reading
+ *
+ * Description:
+ *   Returns 32-bit word starting at byte pointed to by @miter@
+ *   handling any alignment issues.  Bytes past the buffer's end
+ *   are not accessed (read) but are returned as zeroes.  @miter@
+ *   is advanced by 4 bytes or to the end of buffer whichever is
+ *   closer.
+ *
+ * Context:
+ *   Same requirements as in sg_miter_next().
+ *
+ * Returns:
+ *   32-bit word just read.
+ */
+uint32_t cb710_sg_dwiter_read_next_block(struct sg_mapping_iter *miter)
+{
+        uint32_t *ptr = NULL;
+
+        if (likely(sg_dwiter_get_next_block(miter, &ptr)))
+                return ptr ? *ptr : 0;
+
+        return sg_dwiter_read_buffer(miter);
+}
+EXPORT_SYMBOL_GPL(cb710_sg_dwiter_read_next_block);
+
+static void sg_dwiter_write_slow(struct sg_mapping_iter *miter, uint32_t data)
+{
+        size_t len, left = 4;
+        void *addr = &data;
+
+        do {
+                len = min(miter->length - miter->consumed, left);
+                memcpy(miter->addr, addr, len);
+                miter->consumed += len;
+                left -= len;
+                if (!left)
+                        return;
+                addr += len;
+                flush_kernel_dcache_page(miter->page);
+        } while (sg_dwiter_next(miter));
+}
+
+/**
+ * cb710_sg_dwiter_write_next_block() - write next 32-bit word to sg buffer
+ * @miter: sg mapping iterator used for writing
+ *
+ * Description:
+ *   Writes 32-bit word starting at byte pointed to by @miter@
+ *   handling any alignment issues.  Bytes which would be written
+ *   past the buffer's end are silently discarded. @miter@ is
+ *   advanced by 4 bytes or to the end of buffer whichever is closer.
+ *
+ * Context:
+ *   Same requirements as in sg_miter_next().
+ */
+void cb710_sg_dwiter_write_next_block(struct sg_mapping_iter *miter, uint32_t data)
+{
+        uint32_t *ptr = NULL;
+
+        if (likely(sg_dwiter_get_next_block(miter, &ptr))) {
+                if (ptr)
+                        *ptr = data;
+                else
+                        return;
+        } else
+                sg_dwiter_write_slow(miter, data);
+
+        if (miter->length == miter->consumed)
+                flush_kernel_dcache_page(miter->page);
+}
+EXPORT_SYMBOL_GPL(cb710_sg_dwiter_write_next_block);
+