diff options
| author | Masahiro Yamada <yamada.m@jp.panasonic.com> | 2015-01-06 14:28:16 +0900 |
|---|---|---|
| committer | Masahiro Yamada <yamada.m@jp.panasonic.com> | 2015-01-08 23:01:56 +0900 |
| commit | b4ad44baab713af371b1113dd63dd222ba73ba13 (patch) | |
| tree | c75beddbc007f8a1e6dc1bc1855fe37cea7afa55 /arch/arm/include/asm/arch-uniphier/debug-uart.S | |
| parent | 2661dfd0046285e9007c1de126255bee11c0b8cd (diff) | |
ARM: UniPhier: add UART initialization routine for low-level debug
The low-level debugging functions are useful to debug the early boot
stage where the full UART driver is not available.
UniPhier SoCs need to initialize the UART port 0 to use this feature.
The initialization routine is called at the very entry of the
lowlevel_init().
Signed-off-by: Masahiro Yamada <yamada.m@jp.panasonic.com>
Diffstat (limited to 'arch/arm/include/asm/arch-uniphier/debug-uart.S')
| -rw-r--r-- | arch/arm/include/asm/arch-uniphier/debug-uart.S | 24 |
1 files changed, 24 insertions, 0 deletions
diff --git a/arch/arm/include/asm/arch-uniphier/debug-uart.S b/arch/arm/include/asm/arch-uniphier/debug-uart.S new file mode 100644 index 0000000000..af55feed04 --- /dev/null +++ b/arch/arm/include/asm/arch-uniphier/debug-uart.S @@ -0,0 +1,24 @@ +/* + * Copyright (C) 2014 Panasonic Corporation + * Author: Masahiro Yamada <yamada.m@jp.panasonic.com> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <linux/serial_reg.h> + +#if !defined(CONFIG_DEBUG_SEMIHOSTING) +#include CONFIG_DEBUG_LL_INCLUDE +#endif + +#define BAUDRATE 115200 +#define DIV_ROUND(x, d) (((x) + ((d) / 2)) / (d)) +#define DIVISOR DIV_ROUND(UART_CLK, 16 * BAUDRATE) + + .macro init_debug_uart, ra, rb, rc + addruart \ra, \rb, \rc + mov \rb, #UART_LCR_WLEN8 + strb \rb, [\ra, #0x11] + ldr \rb, =DIVISOR + str \rb, [\ra, #0x24] + .endm |