fw_cfg: replace ioport data read with generic method

IOPort read access is limited to one byte at a time by
fw_cfg_comb_valid(). As such, fw_cfg_comb_read() may safely
ignore its size argument (which will always be 1), and simply
call its fw_cfg_read() helper function once, returning 8 bits
via the least significant byte of a 64-bit return value.

This patch replaces fw_cfg_comb_read() with the generic method
fw_cfg_data_read(), and removes the unused fw_cfg_read() helper.

When called with size = 1, fw_cfg_data_read() acts exactly like
fw_cfg_read(), performing the same set of sanity checks, and
executing the while loop at most once (subject to the current
read offset being within range).

Cc: Laszlo Ersek <[email protected]>
Cc: Gerd Hoffmann <[email protected]>
Cc: Marc Marí <[email protected]>
Signed-off-by: Gabriel Somlo <[email protected]>
Message-id: 1446733972[email protected]
Reviewed-by: Laszlo Ersek <[email protected]>
Signed-off-by: Gerd Hoffmann <[email protected]>

diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 8f566f61c106044100895b2a9cd61bd2da98203c..a1d650d5a9f9713dc68db47551287f275293006b 100644 (file)
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -304,23 +304,6 @@ static uint64_t fw_cfg_data_read(void *opaque, hwaddr addr, unsigned size)
     return value;
 }
 
-static uint8_t fw_cfg_read(FWCfgState *s)
-{
-    int arch = !!(s->cur_entry & FW_CFG_ARCH_LOCAL);
-    FWCfgEntry *e = (s->cur_entry == FW_CFG_INVALID) ? NULL :
-                    &s->entries[arch][s->cur_entry & FW_CFG_ENTRY_MASK];
-    uint8_t ret;
-
-    if (s->cur_entry == FW_CFG_INVALID || !e->data || s->cur_offset >= e->len)
-        ret = 0;
-    else {
-        ret = e->data[s->cur_offset++];
-    }
-
-    trace_fw_cfg_read(s, ret);
-    return ret;
-}
-
 static void fw_cfg_data_mem_write(void *opaque, hwaddr addr,
                                   uint64_t value, unsigned size)
 {
@@ -470,12 +453,6 @@ static bool fw_cfg_ctl_mem_valid(void *opaque, hwaddr addr,
     return is_write && size == 2;
 }
 
-static uint64_t fw_cfg_comb_read(void *opaque, hwaddr addr,
-                                 unsigned size)
-{
-    return fw_cfg_read(opaque);
-}
-
 static void fw_cfg_comb_write(void *opaque, hwaddr addr,
                               uint64_t value, unsigned size)
 {
@@ -513,7 +490,7 @@ static const MemoryRegionOps fw_cfg_data_mem_ops = {
 };
 
 static const MemoryRegionOps fw_cfg_comb_mem_ops = {
-    .read = fw_cfg_comb_read,
+    .read = fw_cfg_data_read,
     .write = fw_cfg_comb_write,
     .endianness = DEVICE_LITTLE_ENDIAN,
     .valid.accepts = fw_cfg_comb_valid,