1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Old U-boot compatibility for Acadia
4 *
5 * Author: Josh Boyer <jwboyer@linux.vnet.ibm.com>
6 *
7 * Copyright 2008 IBM Corporation
8 */
9
10#include "ops.h"
11#include "io.h"
12#include "dcr.h"
13#include "stdio.h"
14#include "4xx.h"
15#include "44x.h"
16#include "cuboot.h"
17
18#define TARGET_4xx
19#include "ppcboot.h"
20
21static bd_t bd;
22
23#define CPR_PERD0_SPIDV_MASK 0x000F0000 /* SPI Clock Divider */
24
25#define PLLC_SRC_MASK 0x20000000 /* PLL feedback source */
26
27#define PLLD_FBDV_MASK 0x1F000000 /* PLL feedback divider value */
28#define PLLD_FWDVA_MASK 0x000F0000 /* PLL forward divider A value */
29#define PLLD_FWDVB_MASK 0x00000700 /* PLL forward divider B value */
30
31#define PRIMAD_CPUDV_MASK 0x0F000000 /* CPU Clock Divisor Mask */
32#define PRIMAD_PLBDV_MASK 0x000F0000 /* PLB Clock Divisor Mask */
33#define PRIMAD_OPBDV_MASK 0x00000F00 /* OPB Clock Divisor Mask */
34#define PRIMAD_EBCDV_MASK 0x0000000F /* EBC Clock Divisor Mask */
35
36#define PERD0_PWMDV_MASK 0xFF000000 /* PWM Divider Mask */
37#define PERD0_SPIDV_MASK 0x000F0000 /* SPI Divider Mask */
38#define PERD0_U0DV_MASK 0x0000FF00 /* UART 0 Divider Mask */
39#define PERD0_U1DV_MASK 0x000000FF /* UART 1 Divider Mask */
40
41static void get_clocks(void)
42{
43 unsigned long sysclk, cpr_plld, cpr_pllc, cpr_primad, plloutb, i;
44 unsigned long pllFwdDiv, pllFwdDivB, pllFbkDiv, pllPlbDiv, pllExtBusDiv;
45 unsigned long pllOpbDiv, freqEBC, freqUART, freqOPB;
46 unsigned long div; /* total divisor udiv * bdiv */
47 unsigned long umin; /* minimum udiv */
48 unsigned short diff; /* smallest diff */
49 unsigned long udiv; /* best udiv */
50 unsigned short idiff; /* current diff */
51 unsigned short ibdiv; /* current bdiv */
52 unsigned long est; /* current estimate */
53 unsigned long baud;
54 void *np;
55
56 /* read the sysclk value from the CPLD */
57 sysclk = (in_8(addr: (unsigned char *)0x80000000) == 0xc) ? 66666666 : 33333000;
58
59 /*
60 * Read PLL Mode registers
61 */
62 cpr_plld = CPR0_READ(DCRN_CPR0_PLLD);
63 cpr_pllc = CPR0_READ(DCRN_CPR0_PLLC);
64
65 /*
66 * Determine forward divider A
67 */
68 pllFwdDiv = ((cpr_plld & PLLD_FWDVA_MASK) >> 16);
69
70 /*
71 * Determine forward divider B
72 */
73 pllFwdDivB = ((cpr_plld & PLLD_FWDVB_MASK) >> 8);
74 if (pllFwdDivB == 0)
75 pllFwdDivB = 8;
76
77 /*
78 * Determine FBK_DIV.
79 */
80 pllFbkDiv = ((cpr_plld & PLLD_FBDV_MASK) >> 24);
81 if (pllFbkDiv == 0)
82 pllFbkDiv = 256;
83
84 /*
85 * Read CPR_PRIMAD register
86 */
87 cpr_primad = CPR0_READ(DCRN_CPR0_PRIMAD);
88
89 /*
90 * Determine PLB_DIV.
91 */
92 pllPlbDiv = ((cpr_primad & PRIMAD_PLBDV_MASK) >> 16);
93 if (pllPlbDiv == 0)
94 pllPlbDiv = 16;
95
96 /*
97 * Determine EXTBUS_DIV.
98 */
99 pllExtBusDiv = (cpr_primad & PRIMAD_EBCDV_MASK);
100 if (pllExtBusDiv == 0)
101 pllExtBusDiv = 16;
102
103 /*
104 * Determine OPB_DIV.
105 */
106 pllOpbDiv = ((cpr_primad & PRIMAD_OPBDV_MASK) >> 8);
107 if (pllOpbDiv == 0)
108 pllOpbDiv = 16;
109
110 /* There is a bug in U-Boot that prevents us from using
111 * bd.bi_opbfreq because U-Boot doesn't populate it for
112 * 405EZ. We get to calculate it, yay!
113 */
114 freqOPB = (sysclk *pllFbkDiv) /pllOpbDiv;
115
116 freqEBC = (sysclk * pllFbkDiv) / pllExtBusDiv;
117
118 plloutb = ((sysclk * ((cpr_pllc & PLLC_SRC_MASK) ?
119 pllFwdDivB : pllFwdDiv) *
120 pllFbkDiv) / pllFwdDivB);
121
122 np = find_node_by_alias(alias: "serial0");
123 if (getprop(devp: np, name: "current-speed", buf: &baud, buflen: sizeof(baud)) != sizeof(baud))
124 fatal("no current-speed property\n\r");
125
126 udiv = 256; /* Assume lowest possible serial clk */
127 div = plloutb / (16 * baud); /* total divisor */
128 umin = (plloutb / freqOPB) << 1; /* 2 x OPB divisor */
129 diff = 256; /* highest possible */
130
131 /* i is the test udiv value -- start with the largest
132 * possible (256) to minimize serial clock and constrain
133 * search to umin.
134 */
135 for (i = 256; i > umin; i--) {
136 ibdiv = div / i;
137 est = i * ibdiv;
138 idiff = (est > div) ? (est-div) : (div-est);
139 if (idiff == 0) {
140 udiv = i;
141 break; /* can't do better */
142 } else if (idiff < diff) {
143 udiv = i; /* best so far */
144 diff = idiff; /* update lowest diff*/
145 }
146 }
147 freqUART = plloutb / udiv;
148
149 dt_fixup_cpu_clocks(cpufreq: bd.bi_procfreq, tbfreq: bd.bi_intfreq, busfreq: bd.bi_plb_busfreq);
150 dt_fixup_clock(path: "/plb/ebc", freq: freqEBC);
151 dt_fixup_clock(path: "/plb/opb", freq: freqOPB);
152 dt_fixup_clock(path: "/plb/opb/serial@ef600300", freq: freqUART);
153 dt_fixup_clock(path: "/plb/opb/serial@ef600400", freq: freqUART);
154}
155
156static void acadia_fixups(void)
157{
158 dt_fixup_memory(start: bd.bi_memstart, size: bd.bi_memsize);
159 get_clocks();
160 dt_fixup_mac_address_by_alias(alias: "ethernet0", addr: bd.bi_enetaddr);
161}
162
163void platform_init(unsigned long r3, unsigned long r4, unsigned long r5,
164 unsigned long r6, unsigned long r7)
165{
166 CUBOOT_INIT();
167 platform_ops.fixups = acadia_fixups;
168 platform_ops.exit = ibm40x_dbcr_reset;
169 fdt_init(blob: _dtb_start);
170 serial_console_init();
171}
172

source code of linux/arch/powerpc/boot/cuboot-acadia.c