xref: /openbmc/linux/arch/powerpc/boot/ebony.c (revision c21b37f6)
1 /*
2  * Copyright 2007 David Gibson, IBM Corporation.
3  *
4  * Based on earlier code:
5  *   Copyright (C) Paul Mackerras 1997.
6  *
7  *   Matt Porter <mporter@kernel.crashing.org>
8  *   Copyright 2002-2005 MontaVista Software Inc.
9  *
10  *   Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net>
11  *   Copyright (c) 2003, 2004 Zultys Technologies
12  *
13  * This program is free software; you can redistribute it and/or
14  * modify it under the terms of the GNU General Public License
15  * as published by the Free Software Foundation; either version
16  * 2 of the License, or (at your option) any later version.
17  */
18 #include <stdarg.h>
19 #include <stddef.h>
20 #include "types.h"
21 #include "elf.h"
22 #include "string.h"
23 #include "stdio.h"
24 #include "page.h"
25 #include "ops.h"
26 #include "reg.h"
27 #include "dcr.h"
28 #include "44x.h"
29 
30 extern char _dtb_start[];
31 extern char _dtb_end[];
32 
33 static u8 *ebony_mac0, *ebony_mac1;
34 
35 /* Calculate 440GP clocks */
36 void ibm440gp_fixup_clocks(unsigned int sysclk, unsigned int ser_clk)
37 {
38 	u32 sys0 = mfdcr(DCRN_CPC0_SYS0);
39 	u32 cr0 = mfdcr(DCRN_CPC0_CR0);
40 	u32 cpu, plb, opb, ebc, tb, uart0, uart1, m;
41 	u32 opdv = CPC0_SYS0_OPDV(sys0);
42 	u32 epdv = CPC0_SYS0_EPDV(sys0);
43 
44 	if (sys0 & CPC0_SYS0_BYPASS) {
45 		/* Bypass system PLL */
46 		cpu = plb = sysclk;
47 	} else {
48 		if (sys0 & CPC0_SYS0_EXTSL)
49 			/* PerClk */
50 			m = CPC0_SYS0_FWDVB(sys0) * opdv * epdv;
51 		else
52 			/* CPU clock */
53 			m = CPC0_SYS0_FBDV(sys0) * CPC0_SYS0_FWDVA(sys0);
54 		cpu = sysclk * m / CPC0_SYS0_FWDVA(sys0);
55 		plb = sysclk * m / CPC0_SYS0_FWDVB(sys0);
56 	}
57 
58 	opb = plb / opdv;
59 	ebc = opb / epdv;
60 
61 	/* FIXME: Check if this is for all 440GP, or just Ebony */
62 	if ((mfpvr() & 0xf0000fff) == 0x40000440)
63 		/* Rev. B 440GP, use external system clock */
64 		tb = sysclk;
65 	else
66 		/* Rev. C 440GP, errata force us to use internal clock */
67 		tb = cpu;
68 
69 	if (cr0 & CPC0_CR0_U0EC)
70 		/* External UART clock */
71 		uart0 = ser_clk;
72 	else
73 		/* Internal UART clock */
74 		uart0 = plb / CPC0_CR0_UDIV(cr0);
75 
76 	if (cr0 & CPC0_CR0_U1EC)
77 		/* External UART clock */
78 		uart1 = ser_clk;
79 	else
80 		/* Internal UART clock */
81 		uart1 = plb / CPC0_CR0_UDIV(cr0);
82 
83 	printf("PPC440GP: SysClk = %dMHz (%x)\n\r",
84 	       (sysclk + 500000) / 1000000, sysclk);
85 
86 	dt_fixup_cpu_clocks(cpu, tb, 0);
87 
88 	dt_fixup_clock("/plb", plb);
89 	dt_fixup_clock("/plb/opb", opb);
90 	dt_fixup_clock("/plb/opb/ebc", ebc);
91 	dt_fixup_clock("/plb/opb/serial@40000200", uart0);
92 	dt_fixup_clock("/plb/opb/serial@40000300", uart1);
93 }
94 
95 static void ebony_fixups(void)
96 {
97 	// FIXME: sysclk should be derived by reading the FPGA registers
98 	unsigned long sysclk = 33000000;
99 
100 	ibm440gp_fixup_clocks(sysclk, 6 * 1843200);
101 	ibm44x_fixup_memsize();
102 	dt_fixup_mac_addresses(ebony_mac0, ebony_mac1);
103 	ibm4xx_fixup_ebc_ranges("/plb/opb/ebc");
104 }
105 
106 void ebony_init(void *mac0, void *mac1)
107 {
108 	platform_ops.fixups = ebony_fixups;
109 	platform_ops.exit = ibm44x_dbcr_reset;
110 	ebony_mac0 = mac0;
111 	ebony_mac1 = mac1;
112 	ft_init(_dtb_start, _dtb_end - _dtb_start, 32);
113 	serial_console_init();
114 }
115