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Currently NAND device driver need 8 MMIO access for goldfish nand device access.
MMIO access is expensive in virtualization environment because each MMIO access
will cause a context switch from in-kernel module to qemu user space process.
Through introducing a new batch command, these multiple MMIO access can be
combined into one, thus improve virtualization perofrmance. The booting time in
KVM environment is reduced from 25~26 seconds to 20~21 seconds.
A kernel patch is required to utilize this new batch command.
The patched kernel will detect the batch support through a new flags in
goldfish nand device, while current kernel is not impacted.
Change-Id: Ia460b1ba3c6fde5b1fc6101bb66f8f58e46e6a78
Signed-off-by: Xin Xiaohui <xiaohui.xin@intel.com>
Signed-off-by: Zhang Xiantao <xiantao.zhang@intel.com>
Signed-off-by: Jiang Yunhong <yunhong.jiang@intel.com>
Signed-off-by: Nakajima Jun <jun.nakajima@intel.com>
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