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[v4,6/6] fw_cfg: replace ioport data read with generic method

Message ID 1446586842-21793-7-git-send-email-somlo@cmu.edu
State New
Headers show

Commit Message

Gabriel L. Somlo Nov. 3, 2015, 9:40 p.m. UTC
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 <lersek@redhat.com>
Cc: Gerd Hoffmann <kraxel@redhat.com>
Cc: Marc MarĂ­ <markmb@redhat.com>
Signed-off-by: Gabriel Somlo <somlo@cmu.edu>
Reviewd-by: Laszlo Ersek <lersek@redhat.com>
---
 hw/nvram/fw_cfg.c | 25 +------------------------
 1 file changed, 1 insertion(+), 24 deletions(-)
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Patch

diff --git a/hw/nvram/fw_cfg.c b/hw/nvram/fw_cfg.c
index 9e01b46..2b935ad 100644
--- a/hw/nvram/fw_cfg.c
+++ b/hw/nvram/fw_cfg.c
@@ -303,23 +303,6 @@  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)
 {
@@ -469,12 +452,6 @@  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)
 {
@@ -512,7 +489,7 @@  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,