1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * (C) Copyright 2000-2004
4  * Wolfgang Denk, DENX Software Engineering, wd@denx.de.
5  */
6 
7 #include <common.h>
8 #include <clock_legacy.h>
9 #include <mpc8xx.h>
10 #include <asm/global_data.h>
11 #include <asm/processor.h>
12 #include <asm/io.h>
13 
14 DECLARE_GLOBAL_DATA_PTR;
15 
16 /*
17  * get_clocks() fills in gd->cpu_clock depending on CONFIG_8xx_GCLK_FREQ
18  */
get_clocks(void)19 int get_clocks(void)
20 {
21 	immap_t __iomem *immap = (immap_t __iomem *)CONFIG_SYS_IMMR;
22 	uint sccr = in_be32(&immap->im_clkrst.car_sccr);
23 	uint divider = 1 << (((sccr & SCCR_DFBRG11) >> 11) * 2);
24 
25 	/*
26 	 * If for some reason measuring the gclk frequency won't
27 	 * work, we return the hardwired value.
28 	 * (For example, the cogent CMA286-60 CPU module has no
29 	 * separate oscillator for PITRTCLK)
30 	 */
31 	gd->cpu_clk = CONFIG_8xx_GCLK_FREQ;
32 
33 	if ((sccr & SCCR_EBDF11) == 0) {
34 		/* No Bus Divider active */
35 		gd->bus_clk = gd->cpu_clk;
36 	} else {
37 		/* The MPC8xx has only one BDF: half clock speed */
38 		gd->bus_clk = gd->cpu_clk / 2;
39 	}
40 
41 	gd->arch.brg_clk = gd->cpu_clk / divider;
42 
43 	return 0;
44 }
45