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