Intel Quark SoC has a low end x86 processor with only 400MHz
frequency. Currently it takes about 15 seconds for U-Boot to
boot to shell and the most time consuming part is with MRC,
which is about 12 seconds. MRC programs lots of registers on
the SoC internal message bus indirectly accessed via pci bus.
To speed up the boot, create an optimized version of pci config
read/write dword routines which directly operate on PCI I/O ports.
These two routines are inlined to provide better performance too.
Now it only takes about 3 seconds to finish MRC, which is really
fast (4 times faster than before).
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
In the Quark SoC, some chipset commands are accomplished by utilizing
the internal message network within the host bridge (D0:F0). Accesses
to this network are accomplished by populating the message control
register (MCR), Message Control Register eXtension (MCRX) and the
message data register (MDR).
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
Acked-by: Simon Glass <sjg@chromium.org>
Bin Meng