1 /*
2 * OMAP34xx M2 divider clock code
3 *
4 * Copyright (C) 2007-2008 Texas Instruments, Inc.
5 * Copyright (C) 2007-2010 Nokia Corporation
6 *
7 * Paul Walmsley
8 * Jouni Högander
9 *
10 * Parts of this code are based on code written by
11 * Richard Woodruff, Tony Lindgren, Tuukka Tikkanen, Karthik Dasu
12 *
13 * This program is free software; you can redistribute it and/or modify
14 * it under the terms of the GNU General Public License version 2 as
15 * published by the Free Software Foundation.
16 */
17 #undef DEBUG
18
19 #include <linux/kernel.h>
20 #include <linux/errno.h>
21 #include <linux/clk.h>
22 #include <linux/io.h>
23
24 #include <plat/clock.h>
25 #include <plat/sram.h>
26 #include <plat/sdrc.h>
27
28 #include "clock.h"
29 #include "clock3xxx.h"
30 #include "clock34xx.h"
31 #include "sdrc.h"
32
33 #define CYCLES_PER_MHZ 1000000
34
35 /*
36 * CORE DPLL (DPLL3) M2 divider rate programming functions
37 *
38 * These call into SRAM code to do the actual CM writes, since the SDRAM
39 * is clocked from DPLL3.
40 */
41
42 /**
43 * omap3_core_dpll_m2_set_rate - set CORE DPLL M2 divider
44 * @clk: struct clk * of DPLL to set
45 * @rate: rounded target rate
46 *
47 * Program the DPLL M2 divider with the rounded target rate. Returns
48 * -EINVAL upon error, or 0 upon success.
49 */
omap3_core_dpll_m2_set_rate(struct clk * clk,unsigned long rate)50 int omap3_core_dpll_m2_set_rate(struct clk *clk, unsigned long rate)
51 {
52 u32 new_div = 0;
53 u32 unlock_dll = 0;
54 u32 c;
55 unsigned long validrate, sdrcrate, _mpurate;
56 struct omap_sdrc_params *sdrc_cs0;
57 struct omap_sdrc_params *sdrc_cs1;
58 int ret;
59
60 if (!clk || !rate)
61 return -EINVAL;
62
63 validrate = omap2_clksel_round_rate_div(clk, rate, &new_div);
64 if (validrate != rate)
65 return -EINVAL;
66
67 sdrcrate = sdrc_ick_p->rate;
68 if (rate > clk->rate)
69 sdrcrate <<= ((rate / clk->rate) >> 1);
70 else
71 sdrcrate >>= ((clk->rate / rate) >> 1);
72
73 ret = omap2_sdrc_get_params(sdrcrate, &sdrc_cs0, &sdrc_cs1);
74 if (ret)
75 return -EINVAL;
76
77 if (sdrcrate < MIN_SDRC_DLL_LOCK_FREQ) {
78 pr_debug("clock: will unlock SDRC DLL\n");
79 unlock_dll = 1;
80 }
81
82 /*
83 * XXX This only needs to be done when the CPU frequency changes
84 */
85 _mpurate = arm_fck_p->rate / CYCLES_PER_MHZ;
86 c = (_mpurate << SDRC_MPURATE_SCALE) >> SDRC_MPURATE_BASE_SHIFT;
87 c += 1; /* for safety */
88 c *= SDRC_MPURATE_LOOPS;
89 c >>= SDRC_MPURATE_SCALE;
90 if (c == 0)
91 c = 1;
92
93 pr_debug("clock: changing CORE DPLL rate from %lu to %lu\n", clk->rate,
94 validrate);
95 pr_debug("clock: SDRC CS0 timing params used:"
96 " RFR %08x CTRLA %08x CTRLB %08x MR %08x\n",
97 sdrc_cs0->rfr_ctrl, sdrc_cs0->actim_ctrla,
98 sdrc_cs0->actim_ctrlb, sdrc_cs0->mr);
99 if (sdrc_cs1)
100 pr_debug("clock: SDRC CS1 timing params used: "
101 " RFR %08x CTRLA %08x CTRLB %08x MR %08x\n",
102 sdrc_cs1->rfr_ctrl, sdrc_cs1->actim_ctrla,
103 sdrc_cs1->actim_ctrlb, sdrc_cs1->mr);
104
105 if (sdrc_cs1)
106 omap3_configure_core_dpll(
107 new_div, unlock_dll, c, rate > clk->rate,
108 sdrc_cs0->rfr_ctrl, sdrc_cs0->actim_ctrla,
109 sdrc_cs0->actim_ctrlb, sdrc_cs0->mr,
110 sdrc_cs1->rfr_ctrl, sdrc_cs1->actim_ctrla,
111 sdrc_cs1->actim_ctrlb, sdrc_cs1->mr);
112 else
113 omap3_configure_core_dpll(
114 new_div, unlock_dll, c, rate > clk->rate,
115 sdrc_cs0->rfr_ctrl, sdrc_cs0->actim_ctrla,
116 sdrc_cs0->actim_ctrlb, sdrc_cs0->mr,
117 0, 0, 0, 0);
118 clk->rate = rate;
119
120 return 0;
121 }
122
123