Each controller on the ast2400 has a memory range on which it maps its
flash module slaves. Each slave is assigned a memory segment for its
mapping that can be changed at bootime with the Segment Address
Register. This is not supported in the current implementation so we
are using the defaults provided by the specs.
Each SPI flash slave can then be accessed in two modes: Command and
User. When in User mode, accesses to the memory segment of the slaves
are translated in SPI transfers. When in Command mode, the HW
generates the SPI commands automatically and the memory segment is
accessed as if doing a MMIO. Other SPI controllers call that mode
linear addressing mode.
For this purpose, we are adding below each crontoller an array of
structs gathering for each SPI flash module, a segment rank, a
MemoryRegion to handle the memory accesses and the associated SPI
slave device, which should be a m25p80.
Only the User mode is supported for now but we are preparing ground
for the Command mode. The framework is sufficient to support Linux.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1467138270-32481-8-git-send-email-clg@kaod.org
[PMM: Use g_new0() rather than g_malloc0()]
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
The Aspeed AST2400 soc includes a static memory controller for the BMC
which supports NOR, NAND and SPI flash memory modules. This controller
has two modes : the SMC for the legacy interface which supports only
one module and the FMC for the new interface which supports up to five
modules. The AST2400 also includes a SPI only controller used for the
host firmware, commonly called BIOS on Intel. It can be used in three
mode : a SPI master, SPI slave and SPI pass-through
Below is the initial framework for the SMC controller (FMC mode only)
and the SPI controller: the sysbus object, MMIO for registers
configuration and controls. Each controller has a SPI bus and a
configurable number of CS lines for SPI flash slaves.
The differences between the controllers are small, so they are
abstracted using indirections on the register numbers.
Only SPI flash modules are supported.
Signed-off-by: Cédric Le Goater <clg@kaod.org>
Message-id: 1467138270-32481-7-git-send-email-clg@kaod.org
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: added one missing error_propagate]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
