Re: [PATCH] hw/char/goldfish: Use DMA memory API

[Pierrick Bouvier]

On 7/23/24 11:18, Philippe Mathieu-Daudé wrote:

Rather than using address_space_rw(..., 0 or 1),
use the simpler DMA memory API which expand to
the same code. This allows removing a cast on
the 'buf' variable which is really const. Since
'buf' is only used in the CMD_READ_BUFFER case,
we can reduce its scope.

Signed-off-by: Philippe Mathieu-Daudé <phi...@linaro.org>
---
  hw/char/goldfish_tty.c | 12 ++++++------
  1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/hw/char/goldfish_tty.c b/hw/char/goldfish_tty.c
index f8ff043c396..cdff46bc13b 100644
--- a/hw/char/goldfish_tty.c
+++ b/hw/char/goldfish_tty.c
@@ -16,6 +16,7 @@
  #include "qemu/log.h"
  #include "trace.h"
  #include "exec/address-spaces.h"
+#include "sysemu/dma.h"
  #include "hw/char/goldfish_tty.h"

#define GOLDFISH_TTY_VERSION 1

@@ -69,7 +70,6 @@ static uint64_t goldfish_tty_read(void *opaque, hwaddr addr,
  static void goldfish_tty_cmd(GoldfishTTYState *s, uint32_t cmd)
  {
      uint32_t to_copy;
-    uint8_t *buf;
      uint8_t data_out[GOLFISH_TTY_BUFFER_SIZE];
      int len;
      uint64_t ptr;
@@ -97,8 +97,8 @@ static void goldfish_tty_cmd(GoldfishTTYState *s, uint32_t 
cmd)
          while (len) {
              to_copy = MIN(GOLFISH_TTY_BUFFER_SIZE, len);

- address_space_rw(&address_space_memory, ptr,

-                             MEMTXATTRS_UNSPECIFIED, data_out, to_copy, 0);
+            dma_memory_read_relaxed(&address_space_memory, ptr,
+                                    data_out, to_copy);
              qemu_chr_fe_write_all(&s->chr, data_out, to_copy);

len -= to_copy;

@@ -109,9 +109,9 @@ static void goldfish_tty_cmd(GoldfishTTYState *s, uint32_t 
cmd)
          len = s->data_len;
          ptr = s->data_ptr;
          while (len && !fifo8_is_empty(&s->rx_fifo)) {
-            buf = (uint8_t *)fifo8_pop_buf(&s->rx_fifo, len, &to_copy);
-            address_space_rw(&address_space_memory, ptr,
-                            MEMTXATTRS_UNSPECIFIED, buf, to_copy, 1);
+            const uint8_t *buf = fifo8_pop_buf(&s->rx_fifo, len, &to_copy);
+
+            dma_memory_write_relaxed(&address_space_memory, ptr, buf, to_copy);

len -= to_copy;

              ptr += to_copy;

Reviewed-by: Pierrick Bouvier <pierrick.bouv...@linaro.org>