From: Laszlo Ersek <[email protected]>
We rebase fw_cfg_init_mem() to the new function for compatibility with
current callers.
The behavior of the (big endian) multi-byte data reads is best shown
with a qtest session. Here, we are reading the first six bytes of
the UUID
$ arm-softmmu/qemu-system-arm -M virt -machine accel=qtest \
-qtest stdio -uuid 4600cb32-38ec-4b2f-8acb-81c6ea54f2d8
>>> writew 0x9020008 0x0200
<<< OK
>>> readl 0x9020000
<<< OK 0x000000004600cb32
Remember this is big endian. On big endian machines, it is stored
directly as 0x46 0x00 0xcb 0x32.
On a little endian machine, we have to first swap it, so that it becomes
0x32cb0046. When written to memory, it becomes 0x46 0x00 0xcb 0x32
again.
Reading byte-by-byte works too, of course:
>>> readb 0x9020000
<<< OK 0x0000000000000038
>>> readb 0x9020000
<<< OK 0x00000000000000ec
Here only a single byte is read at a time, so they are read in order
similar to the 1-byte data port that is already in PPC and SPARC
machines.
Signed-off-by: Laszlo Ersek <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>
Message-id: [email protected]
Signed-off-by: Peter Maydell <[email protected]>
---
hw/nvram/fw_cfg.c | 12 +++++++++---
include/hw/nvram/fw_cfg.h | 2 ++
2 files changed, 11 insertions(+), 3 deletions(-)
diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 2950d68..fcdf821 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -663,14 +663,14 @@ FWCfgState *fw_cfg_init_io(uint32_t iobase)
return FW_CFG(dev);
}
-FWCfgState *fw_cfg_init_mem(hwaddr ctl_addr, hwaddr data_addr)
+FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr, hwaddr data_addr,
+ uint32_t data_width)
{
DeviceState *dev;
SysBusDevice *sbd;
dev = qdev_create(NULL, TYPE_FW_CFG_MEM);
- qdev_prop_set_uint32(dev, "data_width",
- fw_cfg_data_mem_ops.valid.max_access_size);
+ qdev_prop_set_uint32(dev, "data_width", data_width);
fw_cfg_init1(dev);
@@ -681,6 +681,12 @@ FWCfgState *fw_cfg_init_mem(hwaddr ctl_addr, hwaddr
data_addr)
return FW_CFG(dev);
}
+FWCfgState *fw_cfg_init_mem(hwaddr ctl_addr, hwaddr data_addr)
+{
+ return fw_cfg_init_mem_wide(ctl_addr, data_addr,
+ fw_cfg_data_mem_ops.valid.max_access_size);
+}
+
FWCfgState *fw_cfg_find(void)
{
diff --git a/include/hw/nvram/fw_cfg.h b/include/hw/nvram/fw_cfg.h
index a99586e..6d8a8ac 100644
--- a/include/hw/nvram/fw_cfg.h
+++ b/include/hw/nvram/fw_cfg.h
@@ -80,6 +80,8 @@ void *fw_cfg_modify_file(FWCfgState *s, const char *filename,
void *data,
size_t len);
FWCfgState *fw_cfg_init_io(uint32_t iobase);
FWCfgState *fw_cfg_init_mem(hwaddr ctl_addr, hwaddr data_addr);
+FWCfgState *fw_cfg_init_mem_wide(hwaddr ctl_addr, hwaddr data_addr,
+ uint32_t data_width);
FWCfgState *fw_cfg_find(void);
--
1.9.1
