This patch adds macros for ns16550 port initialisation
and single char output. The macros can be used in
MIPS asm pbl code.
Signed-off-by: Antony Pavlov <antonynpavlov@xxxxxxxxx>
---
arch/riscv/include/asm/debug_ll_ns16550.h | 186 ++++++++++++++++++++++++++++++
1 file changed, 186 insertions(+)
diff --git a/arch/riscv/include/asm/debug_ll_ns16550.h b/arch/riscv/include/asm/debug_ll_ns16550.h
new file mode 100644
index 000000000..6929453b1
--- /dev/null
+++ b/arch/riscv/include/asm/debug_ll_ns16550.h
@@ -0,0 +1,186 @@
+/*
+ * Copyright (C) 2016, 2017 Antony Pavlov <antonynpavlov@xxxxxxxxx>
+ *
+ * This file is part of barebox.
+ * See file CREDITS for list of people who contributed to this project.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ */
+
+/** @file
+ * This file contains declaration for early output support
+ */
+#ifndef __INCLUDE_RISCV_ASM_DEBUG_LL_NS16550_H__
+#define __INCLUDE_RISCV_ASM_DEBUG_LL_NS16550_H__
+
+#include <linux/kconfig.h>
+
+#ifdef CONFIG_DEBUG_LL
+
+#ifndef DEBUG_LL_UART_ADDR
+#error DEBUG_LL_UART_ADDR is undefined!
+#endif
+
+#ifndef DEBUG_LL_UART_SHIFT
+#error DEBUG_LL_UART_SHIFT is undefined!
+#endif
+
+#ifndef DEBUG_LL_UART_DIVISOR
+#error DEBUG_LL_UART_DIVISOR is undefined!
+#endif
+
+#endif /* CONFIG_DEBUG_LL */
+
+#define UART_THR (0x0 << DEBUG_LL_UART_SHIFT)
+#define UART_RBR (0x0 << DEBUG_LL_UART_SHIFT)
+#define UART_DLL (0x0 << DEBUG_LL_UART_SHIFT)
+#define UART_DLM (0x1 << DEBUG_LL_UART_SHIFT)
+#define UART_LCR (0x3 << DEBUG_LL_UART_SHIFT)
+#define UART_LSR (0x5 << DEBUG_LL_UART_SHIFT)
+
+#define UART_LCR_W 0x07 /* Set UART to 8,N,2 & DLAB = 0 */
+#define UART_LCR_DLAB 0x87 /* Set UART to 8,N,2 & DLAB = 1 */
+
+#define UART_LSR_DR 0x01 /* UART received data present */
+#define UART_LSR_THRE 0x20 /* Xmit holding register empty */
+
+#if defined(DEBUG_LL_UART_IOSIZE32)
+#define UART_REG_L lw
+#define UART_REG_S sw
+#elif defined(DEBUG_LL_UART_IOSIZE8)
+#define UART_REG_L lbu
+#define UART_REG_S sb
+#else
+#error "Please define DEBUG_LL_UART_IOSIZE{8,32}"
+#endif
+
+#ifndef __ASSEMBLY__
+/*
+ * C macros
+ */
+
+#include <asm/io.h>
+
+static inline void PUTC_LL(char ch)
+{
+#ifdef CONFIG_DEBUG_LL
+ while (!(__raw_readl((u8 *)DEBUG_LL_UART_ADDR + UART_LSR) & UART_LSR_THRE))
+ ;
+ __raw_writel(ch, (u8 *)DEBUG_LL_UART_ADDR + UART_THR);
+#endif /* CONFIG_DEBUG_LL */
+}
+
+static inline void debug_ll_ns16550_init(void)
+{
+#ifdef CONFIG_DEBUG_LL
+ __raw_writel(UART_LCR_DLAB, (u8 *)DEBUG_LL_UART_ADDR + UART_LCR);
+ __raw_writel(DEBUG_LL_UART_DIVISOR & 0xff, (u8 *)DEBUG_LL_UART_ADDR + UART_DLL);
+ __raw_writel((DEBUG_LL_UART_DIVISOR >> 8) & 0xff, (u8 *)DEBUG_LL_UART_ADDR + UART_DLM);
+ __raw_writel(UART_LCR_W, (u8 *)DEBUG_LL_UART_ADDR + UART_LCR);
+#endif /* CONFIG_DEBUG_LL */
+}
+#else /* __ASSEMBLY__ */
+/*
+ * Macros for use in assembly language code
+ */
+
+.macro debug_ll_ns16550_init
+#ifdef CONFIG_DEBUG_LL
+ li t0, DEBUG_LL_UART_ADDR
+
+ li t1, UART_LCR_DLAB /* DLAB on */
+ UART_REG_S t1, UART_LCR(t0) /* Write it out */
+
+ li t1, DEBUG_LL_UART_DIVISOR
+ UART_REG_S t1, UART_DLL(t0) /* write low order byte */
+ srl t1, t1, 8
+ UART_REG_S t1, UART_DLM(t0) /* write high order byte */
+
+ li t1, UART_LCR_W /* DLAB off */
+ UART_REG_S t1, UART_LCR(t0) /* Write it out */
+#endif /* CONFIG_DEBUG_LL */
+.endm
+
+/*
+ * output a character in a0
+ */
+.macro debug_ll_outc_a0
+#ifdef CONFIG_DEBUG_LL
+
+ li t0, DEBUG_LL_UART_ADDR
+
+201:
+ UART_REG_L t1, UART_LSR(t0) /* get line status */
+ andi t1, t1, UART_LSR_THRE /* check for transmitter empty */
+ beqz t1, 201b /* try again */
+
+ UART_REG_S a0, UART_THR(t0) /* write the character */
+
+#endif /* CONFIG_DEBUG_LL */
+.endm
+
+/*
+ * output a character
+ */
+.macro debug_ll_outc chr
+#ifdef CONFIG_DEBUG_LL
+ li a0, \chr
+ debug_ll_outc_a0
+#endif /* CONFIG_DEBUG_LL */
+.endm
+
+/*
+ * output CR + NL
+ */
+.macro debug_ll_ns16550_outnl
+#ifdef CONFIG_DEBUG_LL
+ debug_ll_outc '\r'
+ debug_ll_outc '\n'
+#endif /* CONFIG_DEBUG_LL */
+.endm
+
+/*
+ * check character in input buffer
+ * return value:
+ * v0 = 0 no character in input buffer
+ * v0 != 0 character in input buffer
+ */
+.macro debug_ll_tstc
+#ifdef CONFIG_DEBUG_LL
+ li t0, DEBUG_LL_UART_ADDR
+
+ /* get line status and check for data present */
+ UART_REG_L s0, UART_LSR(t0)
+ andi s0, s0, UART_LSR_DR
+
+#endif /* CONFIG_DEBUG_LL */
+.endm
+
+/*
+ * get character to v0
+ */
+.macro debug_ll_getc
+#ifdef CONFIG_DEBUG_LL
+
+204:
+ debug_ll_tstc
+
+ /* try again */
+ beqz s0, 204b
+
+ /* read a character */
+ UART_REG_L s0, UART_RBR(t0)
+
+#endif /* CONFIG_DEBUG_LL */
+.endm
+#endif /* __ASSEMBLY__ */
+
+#endif /* __INCLUDE_RISCV_ASM_DEBUG_LL_NS16550_H__ */
--
2.14.1
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