[RFC,v3,05/17] hw/timer/xilinx_timer: Allow down to 8-bit memory access

Commit Message

Philippe Mathieu-Daudé Nov. 8, 2024, 3:43 p.m. UTC

Allow down to 8-bit access, per the datasheet (reference added
in previous commit):

 "Timer Counter registers are accessed as one of the following types:
  • Byte (8 bits)
  • Half word (2 bytes)
  • Word (4 bytes)"

Signed-off-by: Philippe Mathieu-Daudé <[e-mail]>
Reviewed-by: Anton Johansson <[e-mail]>
Acked-by: Alistair Francis <[e-mail]>
Reviewed-by: Edgar E. Iglesias <[e-mail]>
---
RFC: This breaks the UART qtest, instead of having TX register
receiving 'T' = 0x54, it receives 0x54000000, converted to '\0'
char. It works if we use SWI instead of SBI (storing 32-bit).
---
 hw/timer/xilinx_timer.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

diff --git a/hw/timer/xilinx_timer.c b/hw/timer/xilinx_timer.c
index 383fc8b3c8..c117bff225 100644
--- a/hw/timer/xilinx_timer.c
+++ b/hw/timer/xilinx_timer.c
@@ -198,7 +198,7 @@  static const MemoryRegionOps timer_ops = {
         .max_access_size = 4,
     },
     .valid = {
-        .min_access_size = 4,
+        .min_access_size = 1,
         .max_access_size = 4
     }
 };