PCI: revise VPD access interface

Change PCI VPD API which was only used by sysfs to something usable
in drivers.
   * move iteration over multiple words to the low level
   * use conventional types for arguments
   * add exportable wrapper

Signed-off-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

3 files changed, 110 insertions, 90 deletions

diff --git a/drivers/pci/access.c b/drivers/pci/access.c
index 98ddba94b5b..86ec4ad44bc 100644
--- a/drivers/pci/access.c
+++ b/drivers/pci/access.c
@@ -66,6 +66,39 @@ EXPORT_SYMBOL(pci_bus_write_config_byte);
 EXPORT_SYMBOL(pci_bus_write_config_word);
 EXPORT_SYMBOL(pci_bus_write_config_dword);
 
+
+/**
+ * pci_read_vpd - Read one entry from Vital Product Data
+ * @dev:        pci device struct
+ * @pos:        offset in vpd space
+ * @count:      number of bytes to read
+ * @buf:        pointer to where to store result
+ *
+ */
+ssize_t pci_read_vpd(struct pci_dev *dev, loff_t pos, size_t count, void *buf)
+{
+        if (!dev->vpd || !dev->vpd->ops)
+                return -ENODEV;
+        return dev->vpd->ops->read(dev, pos, count, buf);
+}
+EXPORT_SYMBOL(pci_read_vpd);
+
+/**
+ * pci_write_vpd - Write entry to Vital Product Data
+ * @dev:        pci device struct
+ * @pos:        offset in vpd space
+ * @count:      number of bytes to read
+ * @val:        value to write
+ *
+ */
+ssize_t pci_write_vpd(struct pci_dev *dev, loff_t pos, size_t count, const void *buf)
+{
+        if (!dev->vpd || !dev->vpd->ops)
+                return -ENODEV;
+        return dev->vpd->ops->write(dev, pos, count, buf);
+}
+EXPORT_SYMBOL(pci_write_vpd);
+
 /*
  * The following routines are to prevent the user from accessing PCI config
  * space when it's unsafe to do so.  Some devices require this during BIST and
@@ -176,19 +209,17 @@ static int pci_vpd_pci22_wait(struct pci_dev *dev)
         }
 }
 
-static int pci_vpd_pci22_read(struct pci_dev *dev, int pos, int size,
-                              char *buf)
+static ssize_t pci_vpd_pci22_read(struct pci_dev *dev, loff_t pos, size_t count,
+                                  void *arg)
 {
         struct pci_vpd_pci22 *vpd =
                 container_of(dev->vpd, struct pci_vpd_pci22, base);
-        u32 val;
-        int ret = 0;
-        int begin, end, i;
+        int ret;
+        loff_t end = pos + count;
+        u8 *buf = arg;
 
-        if (pos < 0 || pos > vpd->base.len || size > vpd->base.len  - pos)
+        if (pos < 0 || pos > vpd->base.len || end > vpd->base.len)
                 return -EINVAL;
-        if (size == 0)
-                return 0;
 
         if (mutex_lock_killable(&vpd->lock))
                 return -EINTR;
@@ -196,73 +227,84 @@ static int pci_vpd_pci22_read(struct pci_dev *dev, int pos, int size,
         ret = pci_vpd_pci22_wait(dev);
         if (ret < 0)
                 goto out;
-        ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
-                                         pos & ~3);
-        if (ret < 0)
-                goto out;
 
-        vpd->busy = true;
-        vpd->flag = PCI_VPD_ADDR_F;
-        ret = pci_vpd_pci22_wait(dev);
-        if (ret < 0)
-                goto out;
-        ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA,
-                                         &val);
+        while (pos < end) {
+                u32 val;
+                unsigned int i, skip;
+
+                ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
+                                                 pos & ~3);
+                if (ret < 0)
+                        break;
+                vpd->busy = true;
+                vpd->flag = PCI_VPD_ADDR_F;
+                ret = pci_vpd_pci22_wait(dev);
+                if (ret < 0)
+                        break;
+
+                ret = pci_user_read_config_dword(dev, vpd->cap + PCI_VPD_DATA, &val);
+                if (ret < 0)
+                        break;
+
+                skip = pos & 3;
+                for (i = 0;  i < sizeof(u32); i++) {
+                        if (i >= skip) {
+                                *buf++ = val;
+                                if (++pos == end)
+                                        break;
+                        }
+                        val >>= 8;
+                }
+        }
 out:
         mutex_unlock(&vpd->lock);
-        if (ret < 0)
-                return ret;
-
-        /* Convert to bytes */
-        begin = pos & 3;
-        end = min(4, begin + size);
-        for (i = 0; i < end; ++i) {
-                if (i >= begin)
-                        *buf++ = val;
-                val >>= 8;
-        }
-        return end - begin;
+        return ret ? ret : count;
 }
 
-static int pci_vpd_pci22_write(struct pci_dev *dev, int pos, int size,
-                               const char *buf)
+static ssize_t pci_vpd_pci22_write(struct pci_dev *dev, loff_t pos, size_t count,
+                                   const void *arg)
 {
         struct pci_vpd_pci22 *vpd =
                 container_of(dev->vpd, struct pci_vpd_pci22, base);
-        u32 val;
+        const u8 *buf = arg;
+        loff_t end = pos + count;
         int ret = 0;
 
-        if (pos < 0 || pos > vpd->base.len || pos & 3 ||
-            size > vpd->base.len - pos || size < 4)
+        if (pos < 0 || (pos & 3) || (count & 3) || end > vpd->base.len)
                 return -EINVAL;
 
-        val = (u8) *buf++;
-        val |= ((u8) *buf++) << 8;
-        val |= ((u8) *buf++) << 16;
-        val |= ((u32)(u8) *buf++) << 24;
-
         if (mutex_lock_killable(&vpd->lock))
                 return -EINTR;
+
         ret = pci_vpd_pci22_wait(dev);
         if (ret < 0)
                 goto out;
-        ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA,
-                                          val);
-        if (ret < 0)
-                goto out;
-        ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
-                                         pos | PCI_VPD_ADDR_F);
-        if (ret < 0)
-                goto out;
-        vpd->busy = true;
-        vpd->flag = 0;
-        ret = pci_vpd_pci22_wait(dev);
+
+        while (pos < end) {
+                u32 val;
+
+                val = *buf++;
+                val |= *buf++ << 8;
+                val |= *buf++ << 16;
+                val |= *buf++ << 24;
+
+                ret = pci_user_write_config_dword(dev, vpd->cap + PCI_VPD_DATA, val);
+                if (ret < 0)
+                        break;
+                ret = pci_user_write_config_word(dev, vpd->cap + PCI_VPD_ADDR,
+                                                 pos | PCI_VPD_ADDR_F);
+                if (ret < 0)
+                        break;
+
+                vpd->busy = true;
+                vpd->flag = 0;
+                ret = pci_vpd_pci22_wait(dev);
+
+                pos += sizeof(u32);
+        }
 out:
         mutex_unlock(&vpd->lock);
-        if (ret < 0)
-                return ret;
-
-        return 4;
+        return ret ? ret : count;
 }
 
 static void pci_vpd_pci22_release(struct pci_dev *dev)
@@ -270,7 +312,7 @@ static void pci_vpd_pci22_release(struct pci_dev *dev)
         kfree(container_of(dev->vpd, struct pci_vpd_pci22, base));
 }
 
-static struct pci_vpd_ops pci_vpd_pci22_ops = {
+static const struct pci_vpd_ops pci_vpd_pci22_ops = {
         .read = pci_vpd_pci22_read,
         .write = pci_vpd_pci22_write,
         .release = pci_vpd_pci22_release,
diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
index ea54cedcdfc..c23619fb6c4 100644
--- a/drivers/pci/pci-sysfs.c
+++ b/drivers/pci/pci-sysfs.c
@@ -371,55 +371,33 @@ pci_write_config(struct kobject *kobj, struct bin_attribute *bin_attr,
 }
 
 static ssize_t
-pci_read_vpd(struct kobject *kobj, struct bin_attribute *bin_attr,
-             char *buf, loff_t off, size_t count)
+read_vpd_attr(struct kobject *kobj, struct bin_attribute *bin_attr,
+              char *buf, loff_t off, size_t count)
 {
         struct pci_dev *dev =
                 to_pci_dev(container_of(kobj, struct device, kobj));
-        int end;
-        int ret;
 
         if (off > bin_attr->size)
                 count = 0;
         else if (count > bin_attr->size - off)
                 count = bin_attr->size - off;
-        end = off + count;
-
-        while (off < end) {
-                ret = dev->vpd->ops->read(dev, off, end - off, buf);
-                if (ret < 0)
-                        return ret;
-                buf += ret;
-                off += ret;
-        }
 
-        return count;
+        return pci_read_vpd(dev, off, count, buf);
 }
 
 static ssize_t
-pci_write_vpd(struct kobject *kobj, struct bin_attribute *bin_attr,
-              char *buf, loff_t off, size_t count)
+write_vpd_attr(struct kobject *kobj, struct bin_attribute *bin_attr,
+               char *buf, loff_t off, size_t count)
 {
         struct pci_dev *dev =
                 to_pci_dev(container_of(kobj, struct device, kobj));
-        int end;
-        int ret;
 
         if (off > bin_attr->size)
                 count = 0;
         else if (count > bin_attr->size - off)
                 count = bin_attr->size - off;
-        end = off + count;
-
-        while (off < end) {
-                ret = dev->vpd->ops->write(dev, off, end - off, buf);
-                if (ret < 0)
-                        return ret;
-                buf += ret;
-                off += ret;
-        }
 
-        return count;
+        return pci_write_vpd(dev, off, count, buf);
 }
 
 #ifdef HAVE_PCI_LEGACY
@@ -845,8 +823,8 @@ static int pci_create_capabilities_sysfs(struct pci_dev *dev)
                 attr->size = dev->vpd->len;
                 attr->attr.name = "vpd";
                 attr->attr.mode = S_IRUSR | S_IWUSR;
-                attr->read = pci_read_vpd;
-                attr->write = pci_write_vpd;
+                attr->read = read_vpd_attr;
+                attr->write = write_vpd_attr;
                 retval = sysfs_create_bin_file(&dev->dev.kobj, attr);
                 if (retval) {
                         kfree(dev->vpd->attr);
diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 65deed8bfc0..211fd418f48 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -56,14 +56,14 @@ extern int pci_user_write_config_word(struct pci_dev *dev, int where, u16 val);
 extern int pci_user_write_config_dword(struct pci_dev *dev, int where, u32 val);
 
 struct pci_vpd_ops {
-        int (*read)(struct pci_dev *dev, int pos, int size, char *buf);
-        int (*write)(struct pci_dev *dev, int pos, int size, const char *buf);
+        ssize_t (*read)(struct pci_dev *dev, loff_t pos, size_t count, void *buf);
+        ssize_t (*write)(struct pci_dev *dev, loff_t pos, size_t count, const void *buf);
         void (*release)(struct pci_dev *dev);
 };
 
 struct pci_vpd {
         unsigned int len;
-        struct pci_vpd_ops *ops;
+        const struct pci_vpd_ops *ops;
         struct bin_attribute *attr; /* descriptor for sysfs VPD entry */
 };