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| author | Gabriel L. Somlo <somlo@cmu.edu> | 2016-02-19 13:20:25 -0500 |
|---|---|---|
| committer | Timothy Pearson <tpearson@raptorengineering.com> | 2019-11-29 19:49:13 -0600 |
| commit | df8d94e067f7f080eb4dc5af33755218e23d506a (patch) | |
| tree | f85bc2af4c4361941617ba97193813bb4b51c714 | |
| parent | 92baf99b7f7c2e502552e9d23960306a5c1a4ae9 (diff) | |
| download | hqemu-df8d94e067f7f080eb4dc5af33755218e23d506a.zip hqemu-df8d94e067f7f080eb4dc5af33755218e23d506a.tar.gz | |
fw_cfg: expose control register size in fw_cfg.h
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 Marí <markmb@redhat.com>
Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
Reviewed-by: Laszlo Ersek <lersek@redhat.com>
Reviewed-by: Marc Marí <markmb@redhat.com>
Message-id: 1455906029-25565-2-git-send-email-somlo@cmu.edu
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
| -rw-r--r-- | hw/nvram/fw_cfg.c | 4 | ||||
| -rw-r--r-- | include/hw/nvram/fw_cfg.h | 3 |
2 files changed, 6 insertions, 1 deletions
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" -#define FW_CFG_CTL_SIZE 2 #define FW_CFG_NAME "fw_cfg" #define FW_CFG_PATH "/machine/" FW_CFG_NAME @@ -886,6 +885,9 @@ static void fw_cfg_io_realize(DeviceState *dev, Error **errp) FWCfgIoState *s = FW_CFG_IO(dev); SysBusDevice *sbd = SYS_BUS_DEVICE(dev); + /* 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_ops, 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 @@ #define FW_CFG_INVALID 0xffff +/* width in bytes of fw_cfg control register */ +#define FW_CFG_CTL_SIZE 0x02 + #define FW_CFG_MAX_FILE_PATH 56 #ifndef NO_QEMU_PROTOS |
