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#if defined(ZIMAGE)
153 .word . + 4
154/*
155 * Storage for the state maintained by the macro.
156 *
157 * In the kernel proper, this data is located in arch/arm/mach-tegra/tegra.c.
158 * That's because this header is included from multiple files, and we only
159 * want a single copy of the data. In particular, the UART probing code above
160 * assumes it's running using physical addresses. This is true when this file
161 * is included from head.o, but not when included from debug.o. So we need
162 * to share the probe results between the two copies, rather than having
163 * to re-run the probing again later.
164 *
165 * In the decompressor, we put the storage right here, since common.c
166 * isn't included in the decompressor build. This storage data gets put in
167 * .text even though it's really data, since .data is discarded from the
168 * decompressor. Luckily, .text is writeable in the decompressor, unless
169 * CONFIG_ZBOOT_ROM. That dependency is handled in arch/arm/Kconfig.debug.
170 */
171 /* Debug UART initialization required */
172 .word 1
173 /* Debug UART physical address */
174 .word 0
175 /* Debug UART virtual address */
176 .word 0
177#else
178 .word tegra_uart_config
179#endif
180 .ltorg
181
182 /* Load previously selected UART address */
183100: ldr \rp, [\tmp, #4] @ Load tegra_uart_phys
184 ldr \rv, [\tmp, #8] @ Load tegra_uart_virt
185 .endm
186
187/*
188 * Code below is swiped from <asm/hardware/debug-8250.S>, but add an extra
189 * check to make sure that the UART address is actually valid.
190 */
191
192 .macro senduart, rd, rx
193 cmp \rx, #0
194 strbne \rd, [\rx, #UART_TX << UART_SHIFT]
1951001:
196 .endm
197
198 .macro busyuart, rd, rx
199 cmp \rx, #0
200 beq 1002f
2011001: ldrb \rd, [\rx, #UART_LSR << UART_SHIFT]
202 and \rd, \rd, #UART_LSR_THRE
203 teq \rd, #UART_LSR_THRE
204 bne 1001b
2051002:
206 .endm
207
208 .macro waituartcts, rd, rx
209 cmp \rx, #0
210 beq 1002f
2111001: ldrb \rd, [\rx, #UART_MSR << UART_SHIFT]
212 tst \rd, #UART_MSR_CTS
213 beq 1001b
2141002:
215 .endm
216
217 .macro waituarttxrdy,rd,rx
218 .endm
219

source code of linux/arch/arm/include/debug/tegra.S