tree dba7235dbe07ed1ebd5cb8c37e09dd6fc38cc8af
parent 1281594cb12921a124cd79d3fbd08441c0e89e94
author Petri Gynther <pgynther@google.com> 1453848546 -0800
committer Petri Gynther <pgynther@google.com> 1454013093 -0800

hnvram: fix hnvram partition write flushing

On Chimera with Linux 4.4, hnvram write operations are failing:

NPAPID1600X0002# hnvram -w PLATFORM_NAME=GFCH100
ioctl(hnvram, BLKFLSBUF, 0): Operation not permitted
ioctl(hnvram, BLKFLSBUF, 0): Operation not permitted
[HMX_NVRAM_SetField] field(16)-PLATFORM_NAME error(00000006) : HMX_NVRAM_Write
Unable to write PLATFORM_NAME

This happens because:
1. On Chimera, hnvram partition is on eMMC
2. On Linux 4.4, mmc_blk_ioctl() does not allow write buffer flushes
   for MMC partitions:
   /*
    * The caller must have CAP_SYS_RAWIO, and must be calling this on the
    * whole block device, not on a partition.  This prevents overspray
    * between sibling partitions.
    */
   if ((!capable(CAP_SYS_RAWIO)) || (bdev != bdev->bd_contains))
           return -EPERM;
   }

Fix:
When hnvram lives on MMC partition, flush the entire MMC device.

Change-Id: Idea3c35c8670c78212e940bc9417ab04080d10c2