summaryrefslogtreecommitdiff
path: root/arch/powerpc/cpu/ppc4xx/4xx_uart.c
blob: cad61f3e7c131f723c71e85394283f357e34979d (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
/*
 * (C) Copyright 2000-2006
 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
 *
 * (C) Copyright 2010
 * Stefan Roese, DENX Software Engineering, sr@denx.de.
 *
 * SPDX-License-Identifier:	GPL-2.0	ibm-pibs
 */

#include <common.h>
#include <commproc.h>
#include <asm/processor.h>
#include <asm/io.h>
#include <watchdog.h>
#include <asm/ppc4xx.h>

DECLARE_GLOBAL_DATA_PTR;

#if defined(CONFIG_405GP) || defined(CONFIG_405CR) || \
    defined(CONFIG_405EP) || defined(CONFIG_405EZ) || \
    defined(CONFIG_405EX) || defined(CONFIG_440)

#if defined(CONFIG_440)

#if defined(CONFIG_440GP)
#define CR0_MASK        0x3fff0000
#define CR0_EXTCLK_ENA  0x00600000
#define CR0_UDIV_POS    16
#define UDIV_SUBTRACT	1
#define UART0_SDR	CPC0_CR0
#define MFREG(a, d)	d = mfdcr(a)
#define MTREG(a, d)	mtdcr(a, d)
#else /* #if defined(CONFIG_440GP) */
/* all other 440 PPC's access clock divider via sdr register */
#define CR0_MASK        0xdfffffff
#define CR0_EXTCLK_ENA  0x00800000
#define CR0_UDIV_POS    0
#define UDIV_SUBTRACT	0
#define UART0_SDR	SDR0_UART0
#define UART1_SDR	SDR0_UART1
#if defined(CONFIG_440EP) || defined(CONFIG_440EPX) || \
    defined(CONFIG_440GR) || defined(CONFIG_440GRX) || \
    defined(CONFIG_440SP) || defined(CONFIG_440SPE) || \
    defined(CONFIG_460EX) || defined(CONFIG_460GT)
#define UART2_SDR	SDR0_UART2
#endif
#if defined(CONFIG_440EP) || defined(CONFIG_440EPX) || \
    defined(CONFIG_440GR) || defined(CONFIG_440GRX) || \
    defined(CONFIG_460EX) || defined(CONFIG_460GT)
#define UART3_SDR	SDR0_UART3
#endif
#define MFREG(a, d)	mfsdr(a, d)
#define MTREG(a, d)	mtsdr(a, d)
#endif /* #if defined(CONFIG_440GP) */
#elif defined(CONFIG_405EP) || defined(CONFIG_405EZ)
#define UCR0_MASK       0x0000007f
#define UCR1_MASK       0x00007f00
#define UCR0_UDIV_POS   0
#define UCR1_UDIV_POS   8
#define UDIV_MAX        127
#elif defined(CONFIG_405EX)
#define MFREG(a, d)	mfsdr(a, d)
#define MTREG(a, d)	mtsdr(a, d)
#define CR0_MASK	0x000000ff
#define CR0_EXTCLK_ENA	0x00800000
#define CR0_UDIV_POS	0
#define UDIV_SUBTRACT	0
#define UART0_SDR	SDR0_UART0
#define UART1_SDR	SDR0_UART1
#else /* CONFIG_405GP || CONFIG_405CR */
#define CR0_MASK        0x00001fff
#define CR0_EXTCLK_ENA  0x000000c0
#define CR0_UDIV_POS    1
#define UDIV_MAX        32
#endif

#if defined(CONFIG_405EP) && defined(CONFIG_SYS_EXT_SERIAL_CLOCK)
#error "External serial clock not supported on AMCC PPC405EP!"
#endif

#if (defined(CONFIG_405EX) || defined(CONFIG_405EZ) ||	\
     defined(CONFIG_440)) && !defined(CONFIG_SYS_EXT_SERIAL_CLOCK)
/*
 * For some SoC's, the cpu clock is on divider chain A, UART on
 * divider chain B ... so cpu clock is irrelevant. Get the
 * "optimized" values that are subject to the 1/2 opb clock
 * constraint.
 */
static u16 serial_bdiv(int baudrate, u32 *udiv)
{
	sys_info_t sysinfo;
	u32 div;		/* total divisor udiv * bdiv */
	u32 umin;		/* minimum udiv	*/
	u16 diff;		/* smallest diff */
	u16 idiff;		/* current diff */
	u16 ibdiv;		/* current bdiv */
	u32 i;
	u32 est;		/* current estimate */
	u32 max;
#if defined(CONFIG_405EZ)
	u32 cpr_pllc;
	u32 plloutb;
	u32 reg;
#endif

	get_sys_info(&sysinfo);

#if defined(CONFIG_405EZ)
	/* check the pll feedback source */
	mfcpr(CPR0_PLLC, cpr_pllc);
	plloutb = ((CONFIG_SYS_CLK_FREQ * ((cpr_pllc & PLLC_SRC_MASK) ?
					   sysinfo.pllFwdDivB : sysinfo.pllFwdDiv) *
		    sysinfo.pllFbkDiv) / sysinfo.pllFwdDivB);
	div = plloutb / (16 * baudrate); /* total divisor */
	umin = (plloutb / get_OPB_freq()) << 1;	/* 2 x OPB divisor */
	max = 256;			/* highest possible */
#else /* 405EZ */
	div = sysinfo.freqPLB / (16 * baudrate); /* total divisor */
	umin = sysinfo.pllOpbDiv << 1;	/* 2 x OPB divisor */
	max = 32;			/* highest possible */
#endif /* 405EZ */

	*udiv = diff = max;

	/*
	 * i is the test udiv value -- start with the largest
	 * possible (max) to minimize serial clock and constrain
	 * search to umin.
	 */
	for (i = max; i > umin; i--) {
		ibdiv = div / i;
		est = i * ibdiv;
		idiff = (est > div) ? (est - div) : (div - est);
		if (idiff == 0) {
			*udiv = i;
			break;		/* can't do better */
		} else if (idiff < diff) {
			*udiv = i;	/* best so far */
			diff = idiff;	/* update lowest diff*/
		}
	}

#if defined(CONFIG_405EZ)
	mfcpr(CPR0_PERD0, reg);
	reg &= ~0x0000ffff;
	reg |= ((*udiv - 0) << 8) | (*udiv - 0);
	mtcpr(CPR0_PERD0, reg);
#endif

	return div / *udiv;
}
#endif /* #if (defined(CONFIG_405EP) ... */

/*
 * This function returns the UART clock used by the common
 * NS16550 driver. Additionally the SoC internal divisors for
 * optimal UART baudrate are configured.
 */
int get_serial_clock(void)
{
	u32 clk;
	u32 udiv;
#if !defined(CONFIG_405EZ)
	u32 reg;
#endif
#if !defined(CONFIG_SYS_EXT_SERIAL_CLOCK)
	PPC4xx_SYS_INFO sys_info;
#endif

	/*
	 * Programming of the internal divisors is SoC specific.
	 * Let's handle this in some #ifdef's for the SoC's.
	 */

#if defined(CONFIG_405CR) || defined(CONFIG_405GP)
	reg = mfdcr(CPC0_CR0) & ~CR0_MASK;
#ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
	clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
	udiv = 1;
	reg |= CR0_EXTCLK_ENA;
#else /* CONFIG_SYS_EXT_SERIAL_CLOCK */
	clk = gd->cpu_clk;
#ifdef CONFIG_SYS_405_UART_ERRATA_59
	udiv = 31;			/* Errata 59: stuck at 31 */
#else /* CONFIG_SYS_405_UART_ERRATA_59 */
	{
		u32 tmp = CONFIG_SYS_BASE_BAUD * 16;

		udiv = (clk + tmp / 2) / tmp;
	}
	if (udiv > UDIV_MAX)                    /* max. n bits for udiv */
		udiv = UDIV_MAX;
#endif /* CONFIG_SYS_405_UART_ERRATA_59 */
#endif /* CONFIG_SYS_EXT_SERIAL_CLOCK */
	reg |= (udiv - 1) << CR0_UDIV_POS;	/* set the UART divisor */
	mtdcr (CPC0_CR0, reg);
#ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
	clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
#else
	clk = CONFIG_SYS_BASE_BAUD * 16;
#endif
#endif /* CONFIG_405CR */

#if defined(CONFIG_405EP)
	{
		u32 tmp = CONFIG_SYS_BASE_BAUD * 16;

		reg = mfdcr(CPC0_UCR) & ~(UCR0_MASK | UCR1_MASK);
		clk = gd->cpu_clk;
		udiv = (clk + tmp / 2) / tmp;
		if (udiv > UDIV_MAX)                    /* max. n bits for udiv */
			udiv = UDIV_MAX;
	}
	reg |= udiv << UCR0_UDIV_POS;	        /* set the UART divisor */
	reg |= udiv << UCR1_UDIV_POS;	        /* set the UART divisor */
	mtdcr(CPC0_UCR, reg);
	clk = CONFIG_SYS_BASE_BAUD * 16;
#endif /* CONFIG_405EP */

#if defined(CONFIG_405EX) || defined(CONFIG_440)
	MFREG(UART0_SDR, reg);
	reg &= ~CR0_MASK;

#ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
	reg |= CR0_EXTCLK_ENA;
	udiv = 1;
	clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
#else /* CONFIG_SYS_EXT_SERIAL_CLOCK */
	clk = gd->baudrate * serial_bdiv(gd->baudrate, &udiv) * 16;
#endif /* CONFIG_SYS_EXT_SERIAL_CLOCK */

	reg |= (udiv - UDIV_SUBTRACT) << CR0_UDIV_POS;	/* set the UART divisor */

	/*
	 * Configure input clock to baudrate generator for all
	 * available serial ports here
	 */
	MTREG(UART0_SDR, reg);
#if defined(UART1_SDR)
	MTREG(UART1_SDR, reg);
#endif
#if defined(UART2_SDR)
	MTREG(UART2_SDR, reg);
#endif
#if defined(UART3_SDR)
	MTREG(UART3_SDR, reg);
#endif
#endif /* CONFIG_405EX ... */

#if defined(CONFIG_405EZ)
	clk = gd->baudrate * serial_bdiv(gd->baudrate, &udiv) * 16;
#endif /* CONFIG_405EZ */

	/*
	 * Correct UART frequency in bd-info struct now that
	 * the UART divisor is available
	 */
#ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
	gd->arch.uart_clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
#else
	get_sys_info(&sys_info);
	gd->arch.uart_clk = sys_info.freqUART / udiv;
#endif

	return clk;
}
#endif	/* CONFIG_405GP || CONFIG_405CR */