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 "clock.h"
25 #include "clock3xxx.h"
26 #include "clock34xx.h"
27 #include "sdrc.h"
28 #include "sram.h"
29
30 #define CYCLES_PER_MHZ 1000000
31
32 /*
33 * CORE DPLL (DPLL3) M2 divider rate programming functions
34 *
35 * These call into SRAM code to do the actual CM writes, since the SDRAM
36 * is clocked from DPLL3.
37 */
38
39 /**
40 * omap3_core_dpll_m2_set_rate - set CORE DPLL M2 divider
41 * @clk: struct clk * of DPLL to set
42 * @rate: rounded target rate
43 *
44 * Program the DPLL M2 divider with the rounded target rate. Returns
45 * -EINVAL upon error, or 0 upon success.
46 */
omap3_core_dpll_m2_set_rate(struct clk_hw * hw,unsigned long rate,unsigned long parent_rate)47 int omap3_core_dpll_m2_set_rate(struct clk_hw *hw, unsigned long rate,
48 unsigned long parent_rate)
49 {
50 struct clk_hw_omap *clk = to_clk_hw_omap(hw);
51 u32 new_div = 0;
52 u32 unlock_dll = 0;
53 u32 c;
54 unsigned long validrate, sdrcrate, _mpurate;
55 struct omap_sdrc_params *sdrc_cs0;
56 struct omap_sdrc_params *sdrc_cs1;
57 int ret;
58 unsigned long clkrate;
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 = __clk_get_rate(sdrc_ick_p);
68 clkrate = __clk_get_rate(hw->clk);
69 if (rate > clkrate)
70 sdrcrate <<= ((rate / clkrate) >> 1);
71 else
72 sdrcrate >>= ((clkrate / rate) >> 1);
73
74 ret = omap2_sdrc_get_params(sdrcrate, &sdrc_cs0, &sdrc_cs1);
75 if (ret)
76 return -EINVAL;
77
78 if (sdrcrate < MIN_SDRC_DLL_LOCK_FREQ) {
79 pr_debug("clock: will unlock SDRC DLL\n");
80 unlock_dll = 1;
81 }
82
83 /*
84 * XXX This only needs to be done when the CPU frequency changes
85 */
86 _mpurate = __clk_get_rate(arm_fck_p) / CYCLES_PER_MHZ;
87 c = (_mpurate << SDRC_MPURATE_SCALE) >> SDRC_MPURATE_BASE_SHIFT;
88 c += 1; /* for safety */
89 c *= SDRC_MPURATE_LOOPS;
90 c >>= SDRC_MPURATE_SCALE;
91 if (c == 0)
92 c = 1;
93
94 pr_debug("clock: changing CORE DPLL rate from %lu to %lu\n",
95 clkrate, validrate);
96 pr_debug("clock: SDRC CS0 timing params used: 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: RFR %08x CTRLA %08x CTRLB %08x MR %08x\n",
101 sdrc_cs1->rfr_ctrl, sdrc_cs1->actim_ctrla,
102 sdrc_cs1->actim_ctrlb, sdrc_cs1->mr);
103
104 if (sdrc_cs1)
105 omap3_configure_core_dpll(
106 new_div, unlock_dll, c, rate > clkrate,
107 sdrc_cs0->rfr_ctrl, sdrc_cs0->actim_ctrla,
108 sdrc_cs0->actim_ctrlb, sdrc_cs0->mr,
109 sdrc_cs1->rfr_ctrl, sdrc_cs1->actim_ctrla,
110 sdrc_cs1->actim_ctrlb, sdrc_cs1->mr);
111 else
112 omap3_configure_core_dpll(
113 new_div, unlock_dll, c, rate > clkrate,
114 sdrc_cs0->rfr_ctrl, sdrc_cs0->actim_ctrla,
115 sdrc_cs0->actim_ctrlb, sdrc_cs0->mr,
116 0, 0, 0, 0);
117 return 0;
118 }
119
120