hw/char/goldfish: Use DMA memory API

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

Posted by Philippe Mathieu-Daudé 1 month, 2 weeks ago

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 <philmd@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;
-- 
2.41.0

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

Posted by Philippe Mathieu-Daudé 1 month, 2 weeks ago

On 23/7/24 20:18, 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 <philmd@linaro.org>
> ---
>   hw/char/goldfish_tty.c | 12 ++++++------
>   1 file changed, 6 insertions(+), 6 deletions(-)

Thanks for the quick reviews, patch queued.

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

Posted by Pierrick Bouvier 1 month, 2 weeks ago

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 <philmd@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.bouvier@linaro.org>

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

Posted by Peter Xu 1 month, 2 weeks ago

On Tue, Jul 23, 2024 at 08:18:50PM +0200, 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 <philmd@linaro.org>

Reviewed-by: Peter Xu <peterx@redhat.com>

-- 
Peter Xu