diff mbox series

[4/6] hw/arm/npcm7xx: Remove tswap32() calls and constify smpboot[]

Message ID 20221222215549.86872-5-philmd@linaro.org
State New
Headers show
Series hw/arm: Fix smpboot[] on big-endian hosts and remove tswap32() | expand

Commit Message

Philippe Mathieu-Daudé Dec. 22, 2022, 9:55 p.m. UTC
ARM CPUs fetch instructions in little-endian.

smpboot[] encoded instructions are written in little-endian.

We call tswap32() on the array. tswap32 function swap a 32-bit
value if the target endianness doesn't match the host one.
Otherwise it is a NOP.

* On a little-endian host, the array is stored as it. tswap32()
  is a NOP, and the vCPU fetches the instructions as it, in
  little-endian.

* On a big-endian host, the array is stored as it. tswap32()
  swap the instructions to little-endian, and the vCPU fetches
  the instructions as it, in little-endian.

Using tswap() on system emulation is a bit odd: while the target
particularities might change the system emulation, the host ones
(such its endianness) shouldn't interfere.

We can simplify by using const_le32() to always store the
instructions in the array in little-endian, removing the need
for the dubious tswap().

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
---
Note there is still a tswap() call in npcm7xx_init_fuses()
---
 hw/arm/npcm7xx.c | 49 ++++++++++++++++++++----------------------------
 1 file changed, 20 insertions(+), 29 deletions(-)
diff mbox series

Patch

diff --git a/hw/arm/npcm7xx.c b/hw/arm/npcm7xx.c
index d85cc02765..2976192731 100644
--- a/hw/arm/npcm7xx.c
+++ b/hw/arm/npcm7xx.c
@@ -291,22 +291,18 @@  static const struct {
 static void npcm7xx_write_board_setup(ARMCPU *cpu,
                                       const struct arm_boot_info *info)
 {
-    uint32_t board_setup[] = {
-        0xe59f0010,     /* ldr r0, clk_base_addr */
-        0xe59f1010,     /* ldr r1, pllcon1_value */
-        0xe5801010,     /* str r1, [r0, #16] */
-        0xe59f100c,     /* ldr r1, clksel_value */
-        0xe5801004,     /* str r1, [r0, #4] */
-        0xe12fff1e,     /* bx lr */
-        NPCM7XX_CLK_BA,
-        NPCM7XX_PLLCON1_FIXUP_VAL,
-        NPCM7XX_CLKSEL_FIXUP_VAL,
+    static const uint32_t board_setup[] = {
+        const_le32(0xe59f0010),     /* ldr r0, clk_base_addr */
+        const_le32(0xe59f1010),     /* ldr r1, pllcon1_value */
+        const_le32(0xe5801010),     /* str r1, [r0, #16] */
+        const_le32(0xe59f100c),     /* ldr r1, clksel_value */
+        const_le32(0xe5801004),     /* str r1, [r0, #4] */
+        const_le32(0xe12fff1e),     /* bx lr */
+        const_le32(NPCM7XX_CLK_BA),
+        const_le32(NPCM7XX_PLLCON1_FIXUP_VAL),
+        const_le32(NPCM7XX_CLKSEL_FIXUP_VAL),
     };
-    int i;
 
-    for (i = 0; i < ARRAY_SIZE(board_setup); i++) {
-        board_setup[i] = tswap32(board_setup[i]);
-    }
     rom_add_blob_fixed("board-setup", board_setup, sizeof(board_setup),
                        info->board_setup_addr);
 }
@@ -321,22 +317,17 @@  static void npcm7xx_write_secondary_boot(ARMCPU *cpu,
      * we need to provide our own smpboot stub that can not use 'wfi', it has
      * to spin the secondary CPU until the first CPU writes to the SCRPAD reg.
      */
-    uint32_t smpboot[] = {
-        0xe59f2018,     /* ldr r2, bootreg_addr */
-        0xe3a00000,     /* mov r0, #0 */
-        0xe5820000,     /* str r0, [r2] */
-        0xe320f002,     /* wfe */
-        0xe5921000,     /* ldr r1, [r2] */
-        0xe1110001,     /* tst r1, r1 */
-        0x0afffffb,     /* beq <wfe> */
-        0xe12fff11,     /* bx r1 */
-        NPCM7XX_SMP_BOOTREG_ADDR,
+    static const uint32_t smpboot[] = {
+        const_le32(0xe59f2018),             /* ldr r2, bootreg_addr */
+        const_le32(0xe3a00000),             /* mov r0, #0 */
+        const_le32(0xe5820000),             /* str r0, [r2] */
+        const_le32(0xe320f002),             /* wfe */
+        const_le32(0xe5921000),             /* ldr r1, [r2] */
+        const_le32(0xe1110001),             /* tst r1, r1 */
+        const_le32(0x0afffffb),             /* beq <wfe> */
+        const_le32(0xe12fff11),             /* bx r1 */
+        const_le32(NPCM7XX_SMP_BOOTREG_ADDR),
     };
-    int i;
-
-    for (i = 0; i < ARRAY_SIZE(smpboot); i++) {
-        smpboot[i] = tswap32(smpboot[i]);
-    }
 
     rom_add_blob_fixed("smpboot", smpboot, sizeof(smpboot),
                        NPCM7XX_SMP_LOADER_START);