From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51392) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1adFfS-00005e-GY for qemu-devel@nongnu.org; Tue, 08 Mar 2016 06:19:11 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1adFfP-0001Ar-96 for qemu-devel@nongnu.org; Tue, 08 Mar 2016 06:19:10 -0500 Received: from mx1.redhat.com ([209.132.183.28]:43879) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1adFfP-0001Ae-3b for qemu-devel@nongnu.org; Tue, 08 Mar 2016 06:19:07 -0500 From: Gerd Hoffmann Date: Tue, 8 Mar 2016 12:18:56 +0100 Message-Id: <1457435941-17578-2-git-send-email-kraxel@redhat.com> In-Reply-To: <1457435941-17578-1-git-send-email-kraxel@redhat.com> References: <1457435941-17578-1-git-send-email-kraxel@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PULL 1/6] 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: "Gabriel L. Somlo" , =?UTF-8?q?Marc=20Mar=C3=AD?= , Gerd Hoffmann From: "Gabriel L. Somlo" 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 Message-id: 1455906029-25565-2-git-send-email-somlo@cmu.edu Signed-off-by: Gerd Hoffmann --- 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 f3acb47..7866248 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 @@ -886,6 +885,9 @@ 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 5d19975..4315f4e 100644 --- a/include/hw/nvram/fw_cfg.h +++ b/include/hw/nvram/fw_cfg.h @@ -44,6 +44,9 @@ =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 1.8.3.1