On 12/05/14 19:42, Peter Maydell wrote: > On 30 November 2014 at 16:59, Laszlo Ersek <ler...@redhat.com> wrote: >> fw_cfg already supports exposure over MMIO (used in ppc/mac_newworld.c, >> ppc/mac_oldworld.c, sparc/sun4m.c); we can easily add it to the "virt" >> board. >> >> The mmio register block of fw_cfg is advertized in the device tree. As >> base address we pick 0x09020000, which conforms to the comment preceding >> "a15memmap": it falls in the miscellaneous device I/O range 128MB..256MB, >> and it is aligned at 64KB. The DTB properties follow the documentation in >> the Linux source file "Documentation/devicetree/bindings/arm/fw-cfg.txt". >> >> fw_cfg automatically exports a number of files to the guest; for example, >> "bootorder" (see fw_cfg_machine_reset()). >> >> Signed-off-by: Laszlo Ersek <ler...@redhat.com> >> --- >> >> Notes: >> v2: >> - use a single mmio region of size 0x1000 >> - set "compatible" property to "qemu,fw-cfg-mmio" >> >> hw/arm/virt.c | 21 +++++++++++++++++++++ >> 1 file changed, 21 insertions(+) >> >> diff --git a/hw/arm/virt.c b/hw/arm/virt.c >> index 314e55b..af794ea 100644 >> --- a/hw/arm/virt.c >> +++ b/hw/arm/virt.c >> @@ -68,6 +68,7 @@ enum { >> VIRT_UART, >> VIRT_MMIO, >> VIRT_RTC, >> + VIRT_FW_CFG, >> }; >> >> typedef struct MemMapEntry { >> @@ -107,6 +108,7 @@ static const MemMapEntry a15memmap[] = { >> [VIRT_GIC_CPU] = { 0x08010000, 0x00010000 }, >> [VIRT_UART] = { 0x09000000, 0x00001000 }, >> [VIRT_RTC] = { 0x09010000, 0x00001000 }, >> + [VIRT_FW_CFG] = { 0x09020000, 0x00001000 }, > > Where does this 0x1000 size come from? It's not the size > of the memory region the fw_cfg device exports, and it > means we'll end up telling the f/w in the dtb that the > accessible region is bigger than it really is.
This has been specifically requested in http://thread.gmane.org/gmane.linux.drivers.devicetree/101173/focus=101176 See also the list of changes in http://thread.gmane.org/gmane.linux.drivers.devicetree/101276/focus=101277 > Otherwise this patch looks good to me. > > -- PMM > Thanks Laszlo