From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:36148) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aTzNS-0002GN-99 for qemu-devel@nongnu.org; Thu, 11 Feb 2016 17:06:19 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aTzNR-0006vK-CN for qemu-devel@nongnu.org; Thu, 11 Feb 2016 17:06:18 -0500 From: "Gabriel L. Somlo" Date: Thu, 11 Feb 2016 17:06:01 -0500 Message-Id: <1455228365-13666-2-git-send-email-somlo@cmu.edu> In-Reply-To: <1455228365-13666-1-git-send-email-somlo@cmu.edu> References: <1455228365-13666-1-git-send-email-somlo@cmu.edu> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH v8 1/5] fw_cfg: expose control register size in fw_cfg.h List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: peter.maydell@linaro.org, ehabkost@redhat.com, mst@redhat.com, matt@codeblueprint.co.uk, stefanha@gmail.com, ard.biesheuvel@linaro.org, leif.lindholm@linaro.org, luto@amacapital.net, qemu-arm@nongnu.org, kraxel@redhat.com, pbonzini@redhat.com, imammedo@redhat.com, lersek@redhat.com, rth@twiddle.net Expose the size of the control register (FW_CFG_CTL_SIZE) in fw_cfg.h. Add comment to fw_cfg_io_realize() pointing out that since the 8-bit data register is always subsumed by the 16-bit control register in the port I/O case, we use the control register width as the *total* width of the (classic, non-DMA) port I/O region reserved for the device. Cc: Marc Mar=C3=AD Signed-off-by: Gabriel Somlo Reviewed-by: Laszlo Ersek Reviewed-by: Marc Mar=C3=AD --- hw/nvram/fw_cfg.c | 4 +++- include/hw/nvram/fw_cfg.h | 3 +++ 2 files changed, 6 insertions(+), 1 deletion(-) diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c index 79c5742..ef2a219 100644 --- a/hw/nvram/fw_cfg.c +++ b/hw/nvram/fw_cfg.c @@ -32,7 +32,6 @@ #include "qemu/error-report.h" #include "qemu/config-file.h" =20 -#define FW_CFG_CTL_SIZE 2 #define FW_CFG_NAME "fw_cfg" #define FW_CFG_PATH "/machine/" FW_CFG_NAME =20 @@ -882,6 +881,9 @@ static void fw_cfg_io_realize(DeviceState *dev, Error= **errp) FWCfgIoState *s =3D FW_CFG_IO(dev); SysBusDevice *sbd =3D SYS_BUS_DEVICE(dev); =20 + /* when using port i/o, the 8-bit data register ALWAYS overlaps + * with half of the 16-bit control register. Hence, the total size + * of the i/o region used is FW_CFG_CTL_SIZE */ memory_region_init_io(&s->comb_iomem, OBJECT(s), &fw_cfg_comb_mem_op= s, FW_CFG(s), "fwcfg", FW_CFG_CTL_SIZE); sysbus_add_io(sbd, s->iobase, &s->comb_iomem); diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h index 664eaf6..2667ca9 100644 --- a/include/hw/nvram/fw_cfg.h +++ b/include/hw/nvram/fw_cfg.h @@ -46,6 +46,9 @@ =20 #define FW_CFG_INVALID 0xffff =20 +/* width in bytes of fw_cfg control register */ +#define FW_CFG_CTL_SIZE 0x02 + #define FW_CFG_MAX_FILE_PATH 56 =20 #ifndef NO_QEMU_PROTOS --=20 2.4.3