Messages in this thread | | | Date | Sun, 21 Feb 2016 15:10:30 +0200 | From | "Michael S. Tsirkin" <> | Subject | Re: [PATCH v8 1/4] firmware: introduce sysfs driver for QEMU's fw_cfg device |
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On Sun, Feb 21, 2016 at 08:06:17AM -0500, Gabriel L. Somlo wrote: > > > > > > +#if !(defined(FW_CFG_CTRL_OFF) && defined(FW_CTRL_DATA_OFF)) > > > +# if (defined(CONFIG_ARM) || defined(CONFIG_ARM64)) > > > +# define FW_CFG_CTRL_OFF 0x08 > > > +# define FW_CFG_DATA_OFF 0x00 > > > +# elif (defined(CONFIG_PPC_PMAC) || defined(CONFIG_SPARC32)) /* ppc/mac,sun4m */ > > > +# define FW_CFG_CTRL_OFF 0x00 > > > +# define FW_CFG_DATA_OFF 0x02 > > > +# elif (defined(CONFIG_X86) || defined(CONFIG_SPARC64)) /* x86, sun4u */ > > > +# define FW_CFG_CTRL_OFF 0x00 > > > +# define FW_CFG_DATA_OFF 0x01 > > > +# else > > > +# warning "QEMU FW_CFG may not be available on this architecture!" > > > +# define FW_CFG_CTRL_OFF 0x00 > > > +# define FW_CFG_DATA_OFF 0x01 > > > > Better not try hacks like this, they are hard > > to support down the road. Please only list what is tested and > > actually exposed by QEMU. > > I was looking for a standard way to advertise register offsets within > the ioport or mmio region assigned to fw_cfg, but right now the answer > is "there isn't one", and "register offsets are an arch specific > detail". As such, the only reasonable way I saw was to copy the same > values used in the QEMU source. > > See also: > https://lists.gnu.org/archive/html/qemu-devel/2015-11/msg05037.html > > Thanks much, > --Gabriel
My point is you don't know what will qemu do on these other arches which do not at the moment have fw cfg. So don't try to guess!
-- MST
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