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| author | Pali Rohár <pali@kernel.org> | 2021-10-27 20:57:00 +0200 |
|---|---|---|
| committer | Stefan Roese <sr@denx.de> | 2021-11-03 06:45:27 +0100 |
| commit | 56452295c315397255d05e91940976f68c247d4a (patch) | |
| tree | 0446e4fb8d2c3479237b0adfbb7b769406006745 | |
| parent | cab817d260341244f011f7a0c490df51b33c05aa (diff) | |
| download | u-boot-56452295c315397255d05e91940976f68c247d4a.zip u-boot-56452295c315397255d05e91940976f68c247d4a.tar.gz u-boot-56452295c315397255d05e91940976f68c247d4a.tar.bz2 | |
tools: kwboot: Increase delay after changing baudrate in ARM code
Increase loop cycles from 600000 to 2998272, which should increase delay
from 1ms to about 5ms on 1200 MHz CPU.
The Number 2998272 was chosen as the nearest value around 3000000 which can
be encoded into one ARM mov instruction. It avoids usage of movt instruction
which is not supported by ARMv5te cores.
Signed-off-by: Pali Rohár <pali@kernel.org>
Reviewed-by: Marek Behún <marek.behun@nic.cz>
Reviewed-by: Stefan Roese <sr@denx.de>
| -rw-r--r-- | tools/kwboot.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/tools/kwboot.c b/tools/kwboot.c index a6bfd3d..84294ca 100644 --- a/tools/kwboot.c +++ b/tools/kwboot.c @@ -119,7 +119,7 @@ static unsigned char kwboot_baud_code[] = { /* ; writel(UART_BASE + DLL, new_dll); */ /* ; writel(UART_BASE + DLH, new_dlh); */ /* ; writel(UART_BASE + LCR, lcr & ~DLAB); */ - /* ; msleep(1); */ + /* ; msleep(5); */ /* ; return 0; */ /* ; } */ @@ -130,7 +130,7 @@ static unsigned char kwboot_baud_code[] = { 0x01, 0x00, 0x4d, 0xe3, /* movt r0, #0xd001 */ /* ; r2 = address of preamble string */ - 0xd0, 0x20, 0x8f, 0xe2, /* adr r2, preamble */ + 0xcc, 0x20, 0x8f, 0xe2, /* adr r2, preamble */ /* ; Send preamble string over UART */ /* .Lloop_preamble: */ @@ -177,15 +177,15 @@ static unsigned char kwboot_baud_code[] = { /* ; Read old baudrate value */ /* ; r2 = old_baudrate */ - 0x8c, 0x20, 0x9f, 0xe5, /* ldr r2, old_baudrate */ + 0x88, 0x20, 0x9f, 0xe5, /* ldr r2, old_baudrate */ /* ; Calculate base clock */ /* ; r1 = r2 * r1 */ 0x92, 0x01, 0x01, 0xe0, /* mul r1, r2, r1 */ /* ; Read new baudrate value */ - /* ; r2 = baudrate */ - 0x88, 0x20, 0x9f, 0xe5, /* ldr r2, baudrate */ + /* ; r2 = new_baudrate */ + 0x84, 0x20, 0x9f, 0xe5, /* ldr r2, new_baudrate */ /* ; Calculate new Divisor Latch */ /* ; r1 = DIV_ROUND(r1, r2) = */ @@ -225,10 +225,10 @@ static unsigned char kwboot_baud_code[] = { 0x80, 0x10, 0xc1, 0xe3, /* bic r1, r1, #0x80 */ 0x0c, 0x10, 0x80, 0xe5, /* str r1, [r0, #0x0c] */ - /* ; Sleep 1ms ~~ 600000 cycles at 1200 MHz */ - /* ; r1 = 600000 */ - 0x9f, 0x1d, 0xa0, 0xe3, /* mov r1, #0x27c0 */ - 0x09, 0x10, 0x40, 0xe3, /* movt r1, #0x0009 */ + /* ; Loop 0x2dc000 (2998272) cycles */ + /* ; which is about 5ms on 1200 MHz CPU */ + /* ; r1 = 0x2dc000 */ + 0xb7, 0x19, 0xa0, 0xe3, /* mov r1, #0x2dc000 */ /* .Lloop_sleep: */ 0x01, 0x10, 0x41, 0xe2, /* sub r1, r1, #1 */ 0x00, 0x00, 0x51, 0xe3, /* cmp r1, #0 */ |