2 * (C) Copyright 2000-2006
3 * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
6 * Stefan Roese, DENX Software Engineering, sr@denx.de.
8 * SPDX-License-Identifier: GPL-2.0 IBM-pibs
13 #include <asm/processor.h>
16 #include <asm/ppc4xx.h>
18 DECLARE_GLOBAL_DATA_PTR;
20 #if defined(CONFIG_405GP) || \
21 defined(CONFIG_405EP) || defined(CONFIG_405EZ) || \
22 defined(CONFIG_405EX) || defined(CONFIG_440)
24 #if defined(CONFIG_440)
26 #if defined(CONFIG_440GP)
27 #define CR0_MASK 0x3fff0000
28 #define CR0_EXTCLK_ENA 0x00600000
29 #define CR0_UDIV_POS 16
30 #define UDIV_SUBTRACT 1
31 #define UART0_SDR CPC0_CR0
32 #define MFREG(a, d) d = mfdcr(a)
33 #define MTREG(a, d) mtdcr(a, d)
34 #else /* #if defined(CONFIG_440GP) */
35 /* all other 440 PPC's access clock divider via sdr register */
36 #define CR0_MASK 0xdfffffff
37 #define CR0_EXTCLK_ENA 0x00800000
38 #define CR0_UDIV_POS 0
39 #define UDIV_SUBTRACT 0
40 #define UART0_SDR SDR0_UART0
41 #define UART1_SDR SDR0_UART1
42 #if defined(CONFIG_440EP) || defined(CONFIG_440EPX) || \
43 defined(CONFIG_440GR) || defined(CONFIG_440GRX) || \
44 defined(CONFIG_440SP) || defined(CONFIG_440SPE) || \
45 defined(CONFIG_460EX) || defined(CONFIG_460GT)
46 #define UART2_SDR SDR0_UART2
48 #if defined(CONFIG_440EP) || defined(CONFIG_440EPX) || \
49 defined(CONFIG_440GR) || defined(CONFIG_440GRX) || \
50 defined(CONFIG_460EX) || defined(CONFIG_460GT)
51 #define UART3_SDR SDR0_UART3
53 #define MFREG(a, d) mfsdr(a, d)
54 #define MTREG(a, d) mtsdr(a, d)
55 #endif /* #if defined(CONFIG_440GP) */
56 #elif defined(CONFIG_405EP) || defined(CONFIG_405EZ)
57 #define UCR0_MASK 0x0000007f
58 #define UCR1_MASK 0x00007f00
59 #define UCR0_UDIV_POS 0
60 #define UCR1_UDIV_POS 8
62 #elif defined(CONFIG_405EX)
63 #define MFREG(a, d) mfsdr(a, d)
64 #define MTREG(a, d) mtsdr(a, d)
65 #define CR0_MASK 0x000000ff
66 #define CR0_EXTCLK_ENA 0x00800000
67 #define CR0_UDIV_POS 0
68 #define UDIV_SUBTRACT 0
69 #define UART0_SDR SDR0_UART0
70 #define UART1_SDR SDR0_UART1
71 #else /* CONFIG_405GP */
72 #define CR0_MASK 0x00001fff
73 #define CR0_EXTCLK_ENA 0x000000c0
74 #define CR0_UDIV_POS 1
78 #if defined(CONFIG_405EP) && defined(CONFIG_SYS_EXT_SERIAL_CLOCK)
79 #error "External serial clock not supported on AMCC PPC405EP!"
82 #if (defined(CONFIG_405EX) || defined(CONFIG_405EZ) || \
83 defined(CONFIG_440)) && !defined(CONFIG_SYS_EXT_SERIAL_CLOCK)
85 * For some SoC's, the cpu clock is on divider chain A, UART on
86 * divider chain B ... so cpu clock is irrelevant. Get the
87 * "optimized" values that are subject to the 1/2 opb clock
90 static u16 serial_bdiv(int baudrate, u32 *udiv)
93 u32 div; /* total divisor udiv * bdiv */
94 u32 umin; /* minimum udiv */
95 u16 diff; /* smallest diff */
96 u16 idiff; /* current diff */
97 u16 ibdiv; /* current bdiv */
99 u32 est; /* current estimate */
101 #if defined(CONFIG_405EZ)
107 get_sys_info(&sysinfo);
109 #if defined(CONFIG_405EZ)
110 /* check the pll feedback source */
111 mfcpr(CPR0_PLLC, cpr_pllc);
112 plloutb = ((CONFIG_SYS_CLK_FREQ * ((cpr_pllc & PLLC_SRC_MASK) ?
113 sysinfo.pllFwdDivB : sysinfo.pllFwdDiv) *
114 sysinfo.pllFbkDiv) / sysinfo.pllFwdDivB);
115 div = plloutb / (16 * baudrate); /* total divisor */
116 umin = (plloutb / get_OPB_freq()) << 1; /* 2 x OPB divisor */
117 max = 256; /* highest possible */
119 div = sysinfo.freqPLB / (16 * baudrate); /* total divisor */
120 umin = sysinfo.pllOpbDiv << 1; /* 2 x OPB divisor */
121 max = 32; /* highest possible */
127 * i is the test udiv value -- start with the largest
128 * possible (max) to minimize serial clock and constrain
131 for (i = max; i > umin; i--) {
134 idiff = (est > div) ? (est - div) : (div - est);
137 break; /* can't do better */
138 } else if (idiff < diff) {
139 *udiv = i; /* best so far */
140 diff = idiff; /* update lowest diff*/
144 #if defined(CONFIG_405EZ)
145 mfcpr(CPR0_PERD0, reg);
147 reg |= ((*udiv - 0) << 8) | (*udiv - 0);
148 mtcpr(CPR0_PERD0, reg);
153 #endif /* #if (defined(CONFIG_405EP) ... */
156 * This function returns the UART clock used by the common
157 * NS16550 driver. Additionally the SoC internal divisors for
158 * optimal UART baudrate are configured.
160 int get_serial_clock(void)
164 #if !defined(CONFIG_405EZ)
167 #if !defined(CONFIG_SYS_EXT_SERIAL_CLOCK)
168 PPC4xx_SYS_INFO sys_info;
172 * Programming of the internal divisors is SoC specific.
173 * Let's handle this in some #ifdef's for the SoC's.
176 #if defined(CONFIG_405GP)
177 reg = mfdcr(CPC0_CR0) & ~CR0_MASK;
178 #ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
179 clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
181 reg |= CR0_EXTCLK_ENA;
182 #else /* CONFIG_SYS_EXT_SERIAL_CLOCK */
184 #ifdef CONFIG_SYS_405_UART_ERRATA_59
185 udiv = 31; /* Errata 59: stuck at 31 */
186 #else /* CONFIG_SYS_405_UART_ERRATA_59 */
188 u32 tmp = CONFIG_SYS_BASE_BAUD * 16;
190 udiv = (clk + tmp / 2) / tmp;
192 if (udiv > UDIV_MAX) /* max. n bits for udiv */
194 #endif /* CONFIG_SYS_405_UART_ERRATA_59 */
195 #endif /* CONFIG_SYS_EXT_SERIAL_CLOCK */
196 reg |= (udiv - 1) << CR0_UDIV_POS; /* set the UART divisor */
197 mtdcr (CPC0_CR0, reg);
198 #ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
199 clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
201 clk = CONFIG_SYS_BASE_BAUD * 16;
205 #if defined(CONFIG_405EP)
207 u32 tmp = CONFIG_SYS_BASE_BAUD * 16;
209 reg = mfdcr(CPC0_UCR) & ~(UCR0_MASK | UCR1_MASK);
211 udiv = (clk + tmp / 2) / tmp;
212 if (udiv > UDIV_MAX) /* max. n bits for udiv */
215 reg |= udiv << UCR0_UDIV_POS; /* set the UART divisor */
216 reg |= udiv << UCR1_UDIV_POS; /* set the UART divisor */
217 mtdcr(CPC0_UCR, reg);
218 clk = CONFIG_SYS_BASE_BAUD * 16;
219 #endif /* CONFIG_405EP */
221 #if defined(CONFIG_405EX) || defined(CONFIG_440)
222 MFREG(UART0_SDR, reg);
225 #ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
226 reg |= CR0_EXTCLK_ENA;
228 clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
229 #else /* CONFIG_SYS_EXT_SERIAL_CLOCK */
230 clk = gd->baudrate * serial_bdiv(gd->baudrate, &udiv) * 16;
231 #endif /* CONFIG_SYS_EXT_SERIAL_CLOCK */
233 reg |= (udiv - UDIV_SUBTRACT) << CR0_UDIV_POS; /* set the UART divisor */
236 * Configure input clock to baudrate generator for all
237 * available serial ports here
239 MTREG(UART0_SDR, reg);
240 #if defined(UART1_SDR)
241 MTREG(UART1_SDR, reg);
243 #if defined(UART2_SDR)
244 MTREG(UART2_SDR, reg);
246 #if defined(UART3_SDR)
247 MTREG(UART3_SDR, reg);
249 #endif /* CONFIG_405EX ... */
251 #if defined(CONFIG_405EZ)
252 clk = gd->baudrate * serial_bdiv(gd->baudrate, &udiv) * 16;
253 #endif /* CONFIG_405EZ */
256 * Correct UART frequency in bd-info struct now that
257 * the UART divisor is available
259 #ifdef CONFIG_SYS_EXT_SERIAL_CLOCK
260 gd->arch.uart_clk = CONFIG_SYS_EXT_SERIAL_CLOCK;
262 get_sys_info(&sys_info);
263 gd->arch.uart_clk = sys_info.freqUART / udiv;
268 #endif /* CONFIG_405GP */