From 6c87e3d5967a1d731b5f591a8f0ee6c319c14ca8 Mon Sep 17 00:00:00 2001 From: Laszlo Ersek Date: Mon, 22 Dec 2014 13:11:41 +0100 Subject: fw_cfg_mem: expose the "data_width" property with fw_cfg_init_mem_wide() 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 Signed-off-by: Paolo Bonzini Message-id: 1419250305-31062-8-git-send-email-pbonzini@redhat.com Signed-off-by: Peter Maydell --- hw/nvram/fw_cfg.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) (limited to 'hw/nvram') diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c index 2950d6874b..fcdf821c31 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) { -- cgit v1.2.3