[PATCH v2] uboot: Add the missing disk write operation support

[PATCH v2] uboot: Add the missing disk write operation support

[Cristian Ciocaltea]

uboot_disk_write() is currently lacking the write support
to storage devices because, historically, those devices did not
implement block_write() in U-Boot.

The solution has been tested using a patched U-Boot loading
and booting GRUB in a QEMU vexpress-a9 environment.
The disk write operations were triggered with GRUB's save_env
command.

Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
---

Changes since v1:
 * Fix compiler error when building with '-Werror=discarded-qualifiers':
   passing argument 2 of 'grub_uboot_dev_write' discards 'const'
   qualifier from pointer target type

 grub-core/disk/uboot/ubootdisk.c | 22 ++++++++++++++++------
 grub-core/kern/uboot/uboot.c     | 16 ++++++++++++++++
 include/grub/uboot/uboot.h       |  3 ++-
 3 files changed, 34 insertions(+), 7 deletions(-)

diff --git a/grub-core/disk/uboot/ubootdisk.c b/grub-core/disk/uboot/ubootdisk.c
index a5ce07a99..584a9cbdf 100644
--- a/grub-core/disk/uboot/ubootdisk.c
+++ b/grub-core/disk/uboot/ubootdisk.c
@@ -264,13 +264,23 @@ uboot_disk_read (struct grub_disk *disk,
 }
 
 static grub_err_t
-uboot_disk_write (struct grub_disk *disk __attribute__ ((unused)),
-		  grub_disk_addr_t sector __attribute__ ((unused)),
-		  grub_size_t size __attribute__ ((unused)),
-		  const char *buf __attribute__ ((unused)))
+uboot_disk_write (struct grub_disk *disk,
+		  grub_disk_addr_t offset, grub_size_t numblocks, const char *buf)
 {
-  return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
-		     "attempt to write (not supported)");
+  struct ubootdisk_data *d;
+  int retval;
+
+  d = disk->data;
+
+  retval = grub_uboot_dev_write (d->dev, buf, numblocks, offset);
+  grub_dprintf ("ubootdisk",
+		"retval=%d, numblocks=%d, sector=%llu\n",
+		retval, numblocks, (grub_uint64_t) offset);
+
+  if (retval != 0)
+    return grub_error (GRUB_ERR_IO, "U-Boot disk write error");
+
+  return GRUB_ERR_NONE;
 }
 
 static struct grub_disk_dev grub_ubootdisk_dev = {
diff --git a/grub-core/kern/uboot/uboot.c b/grub-core/kern/uboot/uboot.c
index cf0168e62..3631c044e 100644
--- a/grub-core/kern/uboot/uboot.c
+++ b/grub-core/kern/uboot/uboot.c
@@ -243,6 +243,22 @@ grub_uboot_dev_read (struct device_info *dev, void *buf, grub_size_t blocks,
   return retval;
 }
 
+int
+grub_uboot_dev_write (struct device_info *dev, const void *buf,
+			 grub_size_t blocks, grub_uint32_t start)
+{
+  int retval;
+
+  if (!OPEN_DEV (dev))
+    return -1;
+
+  if (!grub_uboot_syscall (API_DEV_WRITE, &retval, dev, buf,
+			   &blocks, &start))
+    return -1;
+
+  return retval;
+}
+
 int
 grub_uboot_dev_recv (struct device_info *dev, void *buf,
 		     int size, int *real_size)
diff --git a/include/grub/uboot/uboot.h b/include/grub/uboot/uboot.h
index c122de6ab..353ad51c0 100644
--- a/include/grub/uboot/uboot.h
+++ b/include/grub/uboot/uboot.h
@@ -72,7 +72,8 @@ int EXPORT_FUNC (grub_uboot_dev_enum) (void);
 struct device_info * EXPORT_FUNC (grub_uboot_dev_get) (int index);
 int EXPORT_FUNC (grub_uboot_dev_open) (struct device_info *dev);
 int EXPORT_FUNC (grub_uboot_dev_close) (struct device_info *dev);
-int grub_uboot_dev_write (struct device_info *dev, void *buf, int *len);
+int grub_uboot_dev_write (struct device_info *dev, const void *buf,
+			 grub_size_t blocks, grub_uint32_t start);
 int grub_uboot_dev_read (struct device_info *dev, void *buf, grub_size_t blocks,
 			 grub_uint32_t start, grub_size_t * real_blocks);
 int EXPORT_FUNC (grub_uboot_dev_recv) (struct device_info *dev, void *buf,
-- 
2.17.1

Re: [PATCH v2] uboot: Add the missing disk write operation support

[Daniel Kiper]

On Tue, Jan 22, 2019 at 12:02:10PM +0200, Cristian Ciocaltea wrote:
> uboot_disk_write() is currently lacking the write support
> to storage devices because, historically, those devices did not
> implement block_write() in U-Boot.
>
> The solution has been tested using a patched U-Boot loading
> and booting GRUB in a QEMU vexpress-a9 environment.
> The disk write operations were triggered with GRUB's save_env
> command.
>
> Signed-off-by: Cristian Ciocaltea <cristian.ciocaltea@gmail.com>
> Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
> ---
>
> Changes since v1:
>  * Fix compiler error when building with '-Werror=discarded-qualifiers':
>    passing argument 2 of 'grub_uboot_dev_write' discards 'const'
>    qualifier from pointer target type

Pushed. Thanks!

Daniel