xref: /openbmc/linux/arch/arm/include/debug/tegra.S (revision de528723) 
1/* SPDX-License-Identifier: GPL-2.0-only */
2/*
3 * Copyright (C) 2010,2011 Google, Inc.
4 * Copyright (C) 2011-2012 NVIDIA CORPORATION. All Rights Reserved.
5 *
6 * Author:
7 *	Colin Cross <ccross@google.com>
8 *	Erik Gilling <konkers@google.com>
9 *	Doug Anderson <dianders@chromium.org>
10 *	Stephen Warren <swarren@nvidia.com>
11 *
12 * Portions based on mach-omap2's debug-macro.S
13 * Copyright (C) 1994-1999 Russell King
14 */
15
16#include <linux/serial_reg.h>
17
18#define UART_SHIFT 2
19
20/* Physical addresses */
21#define TEGRA_CLK_RESET_BASE		0x60006000
22#define TEGRA_APB_MISC_BASE		0x70000000
23#define TEGRA_UARTA_BASE		0x70006000
24#define TEGRA_UARTB_BASE		0x70006040
25#define TEGRA_UARTC_BASE		0x70006200
26#define TEGRA_UARTD_BASE		0x70006300
27#define TEGRA_UARTE_BASE		0x70006400
28#define TEGRA_PMC_BASE			0x7000e400
29
30#define TEGRA_CLK_RST_DEVICES_L		(TEGRA_CLK_RESET_BASE + 0x04)
31#define TEGRA_CLK_RST_DEVICES_H		(TEGRA_CLK_RESET_BASE + 0x08)
32#define TEGRA_CLK_RST_DEVICES_U		(TEGRA_CLK_RESET_BASE + 0x0c)
33#define TEGRA_CLK_OUT_ENB_L		(TEGRA_CLK_RESET_BASE + 0x10)
34#define TEGRA_CLK_OUT_ENB_H		(TEGRA_CLK_RESET_BASE + 0x14)
35#define TEGRA_CLK_OUT_ENB_U		(TEGRA_CLK_RESET_BASE + 0x18)
36#define TEGRA_PMC_SCRATCH20		(TEGRA_PMC_BASE + 0xa0)
37#define TEGRA_APB_MISC_GP_HIDREV	(TEGRA_APB_MISC_BASE + 0x804)
38
39/*
40 * Must be section-aligned since a section mapping is used early on.
41 * Must not overlap with regions in mach-tegra/io.c:tegra_io_desc[].
42 */
43#define UART_VIRTUAL_BASE		0xfe800000
44
45#define checkuart(rp, rv, lhu, bit, uart) \
46		/* Load address of CLK_RST register */ \
47		ldr	rp, =TEGRA_CLK_RST_DEVICES_##lhu ; \
48		/* Load value from CLK_RST register */ \
49		ldr	rp, [rp, #0] ; \
50		/* Test UART's reset bit */ \
51		tst	rp, #(1 << bit) ; \
52		/* If set, can't use UART; jump to save no UART */ \
53		bne	90f ; \
54		/* Load address of CLK_OUT_ENB register */ \
55		ldr	rp, =TEGRA_CLK_OUT_ENB_##lhu ; \
56		/* Load value from CLK_OUT_ENB register */ \
57		ldr	rp, [rp, #0] ; \
58		/* Test UART's clock enable bit */ \
59		tst	rp, #(1 << bit) ; \
60		/* If clear, can't use UART; jump to save no UART */ \
61		beq	90f ; \
62		/* Passed all tests, load address of UART registers */ \
63		ldr	rp, =TEGRA_UART##uart##_BASE ; \
64		/* Jump to save UART address */ \
65		b 91f
66
67		.macro  addruart, rp, rv, tmp
68		adr	\rp, 99f		@ actual addr of 99f
69		ldr	\rv, [\rp]		@ linked addr is stored there
70		sub	\rv, \rv, \rp		@ offset between the two
71		ldr	\rp, [\rp, #4]		@ linked tegra_uart_config
72		sub	\tmp, \rp, \rv		@ actual tegra_uart_config
73		ldr	\rp, [\tmp]		@ Load tegra_uart_config
74		cmp	\rp, #1			@ needs initialization?
75		bne	100f			@ no; go load the addresses
76		mov	\rv, #0			@ yes; record init is done
77		str	\rv, [\tmp]
78
79#ifdef CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA
80		/* Check ODMDATA */
8110:		ldr	\rp, =TEGRA_PMC_SCRATCH20
82		ldr	\rp, [\rp, #0]		@ Load PMC_SCRATCH20
83		lsr	\rv, \rp, #18		@ 19:18 are console type
84		and	\rv, \rv, #3
85		cmp	\rv, #2			@ 2 and 3 mean DCC, UART
86		beq	11f			@ some boards swap the meaning
87		cmp	\rv, #3			@ so accept either
88		bne	90f
8911:		lsr	\rv, \rp, #15		@ 17:15 are UART ID
90		and	\rv, #7
91		cmp	\rv, #0			@ UART 0?
92		beq	20f
93		cmp	\rv, #1			@ UART 1?
94		beq	21f
95		cmp	\rv, #2			@ UART 2?
96		beq	22f
97		cmp	\rv, #3			@ UART 3?
98		beq	23f
99		cmp	\rv, #4			@ UART 4?
100		beq	24f
101		b	90f			@ invalid
102#endif
103
104#if defined(CONFIG_TEGRA_DEBUG_UARTA) || \
105    defined(CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA)
106		/* Check UART A validity */
10720:		checkuart(\rp, \rv, L, 6, A)
108#endif
109
110#if defined(CONFIG_TEGRA_DEBUG_UARTB) || \
111    defined(CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA)
112		/* Check UART B validity */
11321:		checkuart(\rp, \rv, L, 7, B)
114#endif
115
116#if defined(CONFIG_TEGRA_DEBUG_UARTC) || \
117    defined(CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA)
118		/* Check UART C validity */
11922:		checkuart(\rp, \rv, H, 23, C)
120#endif
121
122#if defined(CONFIG_TEGRA_DEBUG_UARTD) || \
123    defined(CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA)
124		/* Check UART D validity */
12523:		checkuart(\rp, \rv, U, 1, D)
126#endif
127
128#if defined(CONFIG_TEGRA_DEBUG_UARTE) || \
129    defined(CONFIG_TEGRA_DEBUG_UART_AUTO_ODMDATA)
130		/* Check UART E validity */
13124:
132		checkuart(\rp, \rv, U, 2, E)
133#endif
134
135		/* No valid UART found */
13690:		mov	\rp, #0
137		/* fall through */
138
139		/* Record whichever UART we chose */
14091:		str	\rp, [\tmp, #4]		@ Store in tegra_uart_phys
141		cmp	\rp, #0			@ Valid UART address?
142		bne	92f			@ Yes, go process it
143		str	\rp, [\tmp, #8]		@ Store 0 in tegra_uart_virt
144		b	100f			@ Done
14592:		and	\rv, \rp, #0xffffff	@ offset within 1MB section
146		add	\rv, \rv, #UART_VIRTUAL_BASE
147		str	\rv, [\tmp, #8]		@ Store in tegra_uart_virt
148		b	100f
149
150		.align
15199:		.word	.
152		.word	tegra_uart_config
153		.ltorg
154
155		/* Load previously selected UART address */
156100:		ldr	\rp, [\tmp, #4]		@ Load tegra_uart_phys
157		ldr	\rv, [\tmp, #8]		@ Load tegra_uart_virt
158		.endm
159
160/*
161 * Code below is swiped from <asm/hardware/debug-8250.S>, but add an extra
162 * check to make sure that the UART address is actually valid.
163 */
164
165		.macro	senduart, rd, rx
166		cmp	\rx, #0
167		strbne	\rd, [\rx, #UART_TX << UART_SHIFT]
1681001:
169		.endm
170
171		.macro	busyuart, rd, rx
172		cmp	\rx, #0
173		beq	1002f
1741001:		ldrb	\rd, [\rx, #UART_LSR << UART_SHIFT]
175		and	\rd, \rd, #UART_LSR_THRE
176		teq	\rd, #UART_LSR_THRE
177		bne	1001b
1781002:
179		.endm
180
181		.macro	waituart, rd, rx
182#ifdef FLOW_CONTROL
183		cmp	\rx, #0
184		beq	1002f
1851001:		ldrb	\rd, [\rx, #UART_MSR << UART_SHIFT]
186		tst	\rd, #UART_MSR_CTS
187		beq	1001b
1881002:
189#endif
190		.endm
191
192/*
193 * Storage for the state maintained by the macros above.
194 *
195 * In the kernel proper, this data is located in arch/arm/mach-tegra/tegra.c.
196 * That's because this header is included from multiple files, and we only
197 * want a single copy of the data. In particular, the UART probing code above
198 * assumes it's running using physical addresses. This is true when this file
199 * is included from head.o, but not when included from debug.o. So we need
200 * to share the probe results between the two copies, rather than having
201 * to re-run the probing again later.
202 *
203 * In the decompressor, we put the symbol/storage right here, since common.c
204 * isn't included in the decompressor build. This symbol gets put in .text
205 * even though it's really data, since .data is discarded from the
206 * decompressor. Luckily, .text is writeable in the decompressor, unless
207 * CONFIG_ZBOOT_ROM. That dependency is handled in arch/arm/Kconfig.debug.
208 */
209#if defined(ZIMAGE)
210tegra_uart_config:
211	/* Debug UART initialization required */
212	.word 1
213	/* Debug UART physical address */
214	.word 0
215	/* Debug UART virtual address */
216	.word 0
217#endif
218