[PATCH-for-10.0 2/3] hw/char/riscv_htif: Explicit little-endian implementation

[Philippe Mathieu-Daudé]

Since our RISC-V system emulation is only built for little
endian, the HTIF device aims to interface with little endian
memory accesses, thus we can explicit htif_mm_ops:endianness
being DEVICE_LITTLE_ENDIAN.

In that case tswap64() is equivalent to le64_to_cpu(), as in
"convert this 64-bit little-endian value into host cpu order".
Replace to simplify.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
 hw/char/riscv_htif.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/hw/char/riscv_htif.c b/hw/char/riscv_htif.c
index 0345088e8b3..3f84d8d6738 100644
--- a/hw/char/riscv_htif.c
+++ b/hw/char/riscv_htif.c
@@ -29,7 +29,7 @@
 #include "qemu/timer.h"
 #include "qemu/error-report.h"
 #include "exec/address-spaces.h"
-#include "exec/tswap.h"
+#include "qemu/bswap.h"
 #include "sysemu/dma.h"
 #include "sysemu/runstate.h"
 
@@ -212,11 +212,11 @@ static void htif_handle_tohost_write(HTIFState *s, 
uint64_t val_written)
             } else {
                 uint64_t syscall[8];
                 cpu_physical_memory_read(payload, syscall, sizeof(syscall));
-                if (tswap64(syscall[0]) == PK_SYS_WRITE &&
-                    tswap64(syscall[1]) == HTIF_DEV_CONSOLE &&
-                    tswap64(syscall[3]) == HTIF_CONSOLE_CMD_PUTC) {
+                if (le64_to_cpu(syscall[0]) == PK_SYS_WRITE &&
+                    le64_to_cpu(syscall[1]) == HTIF_DEV_CONSOLE &&
+                    le64_to_cpu(syscall[3]) == HTIF_CONSOLE_CMD_PUTC) {
                     uint8_t ch;
-                    cpu_physical_memory_read(tswap64(syscall[2]), &ch, 1);
+                    cpu_physical_memory_read(le64_to_cpu(syscall[2]), &ch, 1);
                     /*
                      * XXX this blocks entire thread. Rewrite to use
                      * qemu_chr_fe_write and background I/O callbacks
@@ -324,6 +324,7 @@ static void htif_mm_write(void *opaque, hwaddr addr,
 static const MemoryRegionOps htif_mm_ops = {
     .read = htif_mm_read,
     .write = htif_mm_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
 };
 
 HTIFState *htif_mm_init(MemoryRegion *address_space, Chardev *chr,
-- 
2.45.2