GNU Linux-libre 4.14.266-gnu1
[releases.git] / arch / powerpc / boot / cpm-serial.c
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
17 struct 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
32 struct 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
42 struct 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
65 struct 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
71 static void *cpcr;
72 static struct cpm_param *param;
73 static struct cpm_smc *smc;
74 static struct cpm_scc *scc;
75 static struct cpm_bd *tbdf, *rbdf;
76 static u32 cpm_cmd;
77 static void *cbd_addr;
78 static u32 cbd_offset;
79
80 static void (*do_cmd)(int op);
81 static void (*enable_port)(void);
82 static 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
88 static 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
99 static 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
110 static 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
116 static 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
122 static 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
128 static 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
134 static int cpm_serial_open(void)
135 {
136         disable_port();
137
138         out_8(&param->rfcr, 0x10);
139         out_8(&param->tfcr, 0x10);
140         out_be16(&param->mrblr, 1);
141         out_be16(&param->maxidl, 0);
142         out_be16(&param->brkec, 0);
143         out_be16(&param->brkln, 0);
144         out_be16(&param->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(&param->rbase, cbd_offset);
158         out_be16(&param->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
166 static 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
178 static unsigned char cpm_serial_tstc(void)
179 {
180         barrier();
181         return !(rbdf->sc & 0x8000);
182 }
183
184 static 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
199 int 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 }