Messages in this thread Patch in this message | | | From | Stafford Horne <> | Subject | [PATCH v2 03/13] openrisc: Add support for liteuart emergency printing | Date | Tue, 17 May 2022 09:55:00 +0900 |
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This patch adds support for sending emergency print output, such as unhandled exception details, to a liteuart serial device. This is the default device available on litex platforms.
If a developer want to use this they should update UART_BASE_ADD to the address of liteuart.
Signed-off-by: Stafford Horne <shorne@gmail.com> --- Changes since v1: - Update for patch 2/12 ifdef changes
arch/openrisc/kernel/head.S | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/arch/openrisc/kernel/head.S b/arch/openrisc/kernel/head.S index 7bfa6e4b60c5..21db50563f97 100644 --- a/arch/openrisc/kernel/head.S +++ b/arch/openrisc/kernel/head.S @@ -1555,7 +1555,18 @@ ENTRY(_emergency_putc) l.movhi r4,hi(UART_BASE_ADD) l.ori r4,r4,lo(UART_BASE_ADD) -#if defined(CONFIG_SERIAL_8250) +#if defined(CONFIG_SERIAL_LITEUART) + /* Check OFF_TXFULL status */ +1: l.lwz r5,4(r4) + l.andi r5,r5,0xff + l.sfnei r5,0 + l.bf 1b + l.nop + + /* Write character */ + l.andi r7,r7,0xff + l.sw 0(r4),r7 +#elif defined(CONFIG_SERIAL_8250) /* Check UART LSR THRE (hold) bit */ l.addi r6,r0,0x20 1: l.lbz r5,5(r4) -- 2.31.1
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