From: "Marek Behún" <kabel@kernel.org>
To: Stefan Roese <sr@denx.de>
Cc: u-boot@lists.denx.de, "Pali Rohár" <pali@kernel.org>,
"Marek Behún" <marek.behun@nic.cz>
Subject: [PATCH u-boot-marvell 3/5] tools: kwboot: Increase delay after changing baudrate in ARM code
Date: Wed, 27 Oct 2021 20:57:00 +0200 [thread overview]
Message-ID: <20211027185702.8186-4-kabel@kernel.org> (raw)
In-Reply-To: <20211027185702.8186-1-kabel@kernel.org>
From: Pali Rohár <pali@kernel.org>
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>
---
tools/kwboot.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
diff --git a/tools/kwboot.c b/tools/kwboot.c
index a6bfd3d4ce..84294cadfe 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 */
--
2.32.0
next prev parent reply other threads:[~2021-10-27 18:57 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-27 18:56 [PATCH u-boot-marvell 0/5] kwboot fix for AXP + some others Marek Behún
2021-10-27 18:56 ` [PATCH u-boot-marvell 1/5] tools: kwboot: Fix sending retry of last header packet Marek Behún
2021-11-03 5:37 ` Stefan Roese
2021-10-27 18:56 ` [PATCH u-boot-marvell 2/5] tools: kwboot: Do not call tcdrain() after each sent packet Marek Behún
2021-11-03 5:38 ` Stefan Roese
2021-10-27 18:57 ` Marek Behún [this message]
2021-11-03 5:38 ` [PATCH u-boot-marvell 3/5] tools: kwboot: Increase delay after changing baudrate in ARM code Stefan Roese
2021-10-27 18:57 ` [PATCH u-boot-marvell 4/5] tools: kwboot: Replace ARM mov + movt instruction pair by mov + orr Marek Behún
2021-11-03 5:38 ` Stefan Roese
2021-10-27 18:57 ` [PATCH u-boot-marvell 5/5] tools: kwboot: Do not use stack when setting baudrate back to default value Marek Behún
2021-11-03 5:38 ` Stefan Roese
2021-11-03 7:46 ` [PATCH u-boot-marvell 0/5] kwboot fix for AXP + some others Stefan Roese
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