diff options
Diffstat (limited to 'arch/riscv/include/asm/debug_ll_ns16550.h')
| -rw-r--r-- | arch/riscv/include/asm/debug_ll_ns16550.h | 182 |
1 files changed, 182 insertions, 0 deletions
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 0000000000..e891cbda25 --- /dev/null +++ b/arch/riscv/include/asm/debug_ll_ns16550.h @@ -0,0 +1,182 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2016, 2017 Antony Pavlov <antonynpavlov@gmail.com> + * + * This file is part of barebox. + * + * 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__ */ |