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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * CPM serial console support.
4 *
5 * Copyright 2007 Freescale Semiconductor, Inc.
6 * Author: Scott Wood <scottwood@freescale.com>
7 *
8 * It is assumed that the firmware (or the platform file) has already set
9 * up the port.
10 */
11
12#include "types.h"
13#include "io.h"
14#include "ops.h"
15#include "page.h"
16
17struct cpm_scc {
18 u32 gsmrl;
19 u32 gsmrh;
20 u16 psmr;
21 u8 res1[2];
22 u16 todr;
23 u16 dsr;
24 u16 scce;
25 u8 res2[2];
26 u16 sccm;
27 u8 res3;
28 u8 sccs;
29 u8 res4[8];
30};
31
32struct cpm_smc {
33 u8 res1[2];
34 u16 smcmr;
35 u8 res2[2];
36 u8 smce;
37 u8 res3[3];
38 u8 smcm;
39 u8 res4[5];
40};
41
42struct cpm_param {
43 u16 rbase;
44 u16 tbase;
45 u8 rfcr;
46 u8 tfcr;
47 u16 mrblr;
48 u32 rstate;
49 u8 res1[4];
50 u16 rbptr;
51 u8 res2[6];
52 u32 tstate;
53 u8 res3[4];
54 u16 tbptr;
55 u8 res4[6];
56 u16 maxidl;
57 u16 idlc;
58 u16 brkln;
59 u16 brkec;
60 u16 brkcr;
61 u16 rmask;
62 u8 res5[4];
63};
64
65struct cpm_bd {
66 u16 sc; /* Status and Control */
67 u16 len; /* Data length in buffer */
68 u8 *addr; /* Buffer address in host memory */
69};
70
71static void *cpcr;
72static struct cpm_param *param;
73static struct cpm_smc *smc;
74static struct cpm_scc *scc;
75static struct cpm_bd *tbdf, *rbdf;
76static u32 cpm_cmd;
77static void *cbd_addr;
78static u32 cbd_offset;
79
80static void (*do_cmd)(int op);
81static void (*enable_port)(void);
82static void (*disable_port)(void);
83
84#define CPM_CMD_STOP_TX 4
85#define CPM_CMD_RESTART_TX 6
86#define CPM_CMD_INIT_RX_TX 0
87
88static void cpm1_cmd(int op)
89{
90 while (in_be16(cpcr) & 1)
91 ;
92
93 out_be16(cpcr, (op << 8) | cpm_cmd | 1);
94
95 while (in_be16(cpcr) & 1)
96 ;
97}
98
99static void cpm2_cmd(int op)
100{
101 while (in_be32(cpcr) & 0x10000)
102 ;
103
104 out_be32(cpcr, op | cpm_cmd | 0x10000);
105
106 while (in_be32(cpcr) & 0x10000)
107 ;
108}
109
110static void smc_disable_port(void)
111{
112 do_cmd(CPM_CMD_STOP_TX);
113 out_be16(&smc->smcmr, in_be16(&smc->smcmr) & ~3);
114}
115
116static void scc_disable_port(void)
117{
118 do_cmd(CPM_CMD_STOP_TX);
119 out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) & ~0x30);
120}
121
122static void smc_enable_port(void)
123{
124 out_be16(&smc->smcmr, in_be16(&smc->smcmr) | 3);
125 do_cmd(CPM_CMD_RESTART_TX);
126}
127
128static void scc_enable_port(void)
129{
130 out_be32(&scc->gsmrl, in_be32(&scc->gsmrl) | 0x30);
131 do_cmd(CPM_CMD_RESTART_TX);
132}
133
134static int cpm_serial_open(void)
135{
136 disable_port();
137
138 out_8(¶m->rfcr, 0x10);
139 out_8(¶m->tfcr, 0x10);
140 out_be16(¶m->mrblr, 1);
141 out_be16(¶m->maxidl, 0);
142 out_be16(¶m->brkec, 0);
143 out_be16(¶m->brkln, 0);
144 out_be16(¶m->brkcr, 0);
145
146 rbdf = cbd_addr;
147 rbdf->addr = (u8 *)rbdf - 1;
148 rbdf->sc = 0xa000;
149 rbdf->len = 1;
150
151 tbdf = rbdf + 1;
152 tbdf->addr = (u8 *)rbdf - 2;
153 tbdf->sc = 0x2000;
154 tbdf->len = 1;
155
156 sync();
157 out_be16(¶m->rbase, cbd_offset);
158 out_be16(¶m->tbase, cbd_offset + sizeof(struct cpm_bd));
159
160 do_cmd(CPM_CMD_INIT_RX_TX);
161
162 enable_port();
163 return 0;
164}
165
166static void cpm_serial_putc(unsigned char c)
167{
168 while (tbdf->sc & 0x8000)
169 barrier();
170
171 sync();
172
173 tbdf->addr[0] = c;
174 eieio();
175 tbdf->sc |= 0x8000;
176}
177
178static unsigned char cpm_serial_tstc(void)
179{
180 barrier();
181 return !(rbdf->sc & 0x8000);
182}
183
184static unsigned char cpm_serial_getc(void)
185{
186 unsigned char c;
187
188 while (!cpm_serial_tstc())
189 ;
190
191 sync();
192 c = rbdf->addr[0];
193 eieio();
194 rbdf->sc |= 0x8000;
195
196 return c;
197}
198
199int cpm_console_init(void *devp, struct serial_console_data *scdp)
200{
201 void *vreg[2];
202 u32 reg[2];
203 int is_smc = 0, is_cpm2 = 0;
204 void *parent, *muram;
205 void *muram_addr;
206 unsigned long muram_offset, muram_size;
207
208 if (dt_is_compatible(devp, "fsl,cpm1-smc-uart")) {
209 is_smc = 1;
210 } else if (dt_is_compatible(devp, "fsl,cpm2-scc-uart")) {
211 is_cpm2 = 1;
212 } else if (dt_is_compatible(devp, "fsl,cpm2-smc-uart")) {
213 is_cpm2 = 1;
214 is_smc = 1;
215 }
216
217 if (is_smc) {
218 enable_port = smc_enable_port;
219 disable_port = smc_disable_port;
220 } else {
221 enable_port = scc_enable_port;
222 disable_port = scc_disable_port;
223 }
224
225 if (is_cpm2)
226 do_cmd = cpm2_cmd;
227 else
228 do_cmd = cpm1_cmd;
229
230 if (getprop(devp, "fsl,cpm-command", &cpm_cmd, 4) < 4)
231 return -1;
232
233 if (dt_get_virtual_reg(devp, vreg, 2) < 2)
234 return -1;
235
236 if (is_smc)
237 smc = vreg[0];
238 else
239 scc = vreg[0];
240
241 param = vreg[1];
242
243 parent = get_parent(devp);
244 if (!parent)
245 return -1;
246
247 if (dt_get_virtual_reg(parent, &cpcr, 1) < 1)
248 return -1;
249
250 muram = finddevice("/soc/cpm/muram/data");
251 if (!muram)
252 return -1;
253
254 /* For bootwrapper-compatible device trees, we assume that the first
255 * entry has at least 128 bytes, and that #address-cells/#data-cells
256 * is one for both parent and child.
257 */
258
259 if (dt_get_virtual_reg(muram, &muram_addr, 1) < 1)
260 return -1;
261
262 if (getprop(muram, "reg", reg, 8) < 8)
263 return -1;
264
265 muram_offset = reg[0];
266 muram_size = reg[1];
267
268 /* Store the buffer descriptors at the end of the first muram chunk.
269 * For SMC ports on CPM2-based platforms, relocate the parameter RAM
270 * just before the buffer descriptors.
271 */
272
273 cbd_offset = muram_offset + muram_size - 2 * sizeof(struct cpm_bd);
274
275 if (is_cpm2 && is_smc) {
276 u16 *smc_base = (u16 *)param;
277 u16 pram_offset;
278
279 pram_offset = cbd_offset - 64;
280 pram_offset = _ALIGN_DOWN(pram_offset, 64);
281
282 disable_port();
283 out_be16(smc_base, pram_offset);
284 param = muram_addr - muram_offset + pram_offset;
285 }
286
287 cbd_addr = muram_addr - muram_offset + cbd_offset;
288
289 scdp->open = cpm_serial_open;
290 scdp->putc = cpm_serial_putc;
291 scdp->getc = cpm_serial_getc;
292 scdp->tstc = cpm_serial_tstc;
293
294 return 0;
295}