omap-2-3-common = irq.o sdrc.o omap_hwmod.o
omap-3-4-common = dpll3xxx.o
prcm-common = prcm.o powerdomain.o
-clock-common = clock.o clock_common_data.o clockdomain.o
+clock-common = clock.o clock_common_data.o \
+ clockdomain.o clkt_dpll.o
obj-$(CONFIG_ARCH_OMAP2) += $(omap-2-3-common) $(prcm-common) $(clock-common)
obj-$(CONFIG_ARCH_OMAP3) += $(omap-2-3-common) $(prcm-common) $(clock-common) \
--- /dev/null
+/*
+ * OMAP2/3/4 DPLL clock functions
+ *
+ * Copyright (C) 2005-2008 Texas Instruments, Inc.
+ * Copyright (C) 2004-2010 Nokia Corporation
+ *
+ * Contacts:
+ * Richard Woodruff <r-woodruff2@ti.com>
+ * Paul Walmsley
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+#include <asm/div64.h>
+
+#include <plat/clock.h>
+
+#include "clock.h"
+#include "cm.h"
+#include "cm-regbits-24xx.h"
+#include "cm-regbits-34xx.h"
+
+/* DPLL rate rounding: minimum DPLL multiplier, divider values */
+#define DPLL_MIN_MULTIPLIER 1
+#define DPLL_MIN_DIVIDER 1
+
+/* Possible error results from _dpll_test_mult */
+#define DPLL_MULT_UNDERFLOW -1
+
+/*
+ * Scale factor to mitigate roundoff errors in DPLL rate rounding.
+ * The higher the scale factor, the greater the risk of arithmetic overflow,
+ * but the closer the rounded rate to the target rate. DPLL_SCALE_FACTOR
+ * must be a power of DPLL_SCALE_BASE.
+ */
+#define DPLL_SCALE_FACTOR 64
+#define DPLL_SCALE_BASE 2
+#define DPLL_ROUNDING_VAL ((DPLL_SCALE_BASE / 2) * \
+ (DPLL_SCALE_FACTOR / DPLL_SCALE_BASE))
+
+/* DPLL valid Fint frequency band limits - from 34xx TRM Section 4.7.6.2 */
+#define DPLL_FINT_BAND1_MIN 750000
+#define DPLL_FINT_BAND1_MAX 2100000
+#define DPLL_FINT_BAND2_MIN 7500000
+#define DPLL_FINT_BAND2_MAX 21000000
+
+/* _dpll_test_fint() return codes */
+#define DPLL_FINT_UNDERFLOW -1
+#define DPLL_FINT_INVALID -2
+
+/* Private functions */
+
+/*
+ * _dpll_test_fint - test whether an Fint value is valid for the DPLL
+ * @clk: DPLL struct clk to test
+ * @n: divider value (N) to test
+ *
+ * Tests whether a particular divider @n will result in a valid DPLL
+ * internal clock frequency Fint. See the 34xx TRM 4.7.6.2 "DPLL Jitter
+ * Correction". Returns 0 if OK, -1 if the enclosing loop can terminate
+ * (assuming that it is counting N upwards), or -2 if the enclosing loop
+ * should skip to the next iteration (again assuming N is increasing).
+ */
+static int _dpll_test_fint(struct clk *clk, u8 n)
+{
+ struct dpll_data *dd;
+ long fint;
+ int ret = 0;
+
+ dd = clk->dpll_data;
+
+ /* DPLL divider must result in a valid jitter correction val */
+ fint = clk->parent->rate / (n + 1);
+ if (fint < DPLL_FINT_BAND1_MIN) {
+
+ pr_debug("rejecting n=%d due to Fint failure, "
+ "lowering max_divider\n", n);
+ dd->max_divider = n;
+ ret = DPLL_FINT_UNDERFLOW;
+
+ } else if (fint > DPLL_FINT_BAND1_MAX &&
+ fint < DPLL_FINT_BAND2_MIN) {
+
+ pr_debug("rejecting n=%d due to Fint failure\n", n);
+ ret = DPLL_FINT_INVALID;
+
+ } else if (fint > DPLL_FINT_BAND2_MAX) {
+
+ pr_debug("rejecting n=%d due to Fint failure, "
+ "boosting min_divider\n", n);
+ dd->min_divider = n;
+ ret = DPLL_FINT_INVALID;
+
+ }
+
+ return ret;
+}
+
+static unsigned long _dpll_compute_new_rate(unsigned long parent_rate,
+ unsigned int m, unsigned int n)
+{
+ unsigned long long num;
+
+ num = (unsigned long long)parent_rate * m;
+ do_div(num, n);
+ return num;
+}
+
+/*
+ * _dpll_test_mult - test a DPLL multiplier value
+ * @m: pointer to the DPLL m (multiplier) value under test
+ * @n: current DPLL n (divider) value under test
+ * @new_rate: pointer to storage for the resulting rounded rate
+ * @target_rate: the desired DPLL rate
+ * @parent_rate: the DPLL's parent clock rate
+ *
+ * This code tests a DPLL multiplier value, ensuring that the
+ * resulting rate will not be higher than the target_rate, and that
+ * the multiplier value itself is valid for the DPLL. Initially, the
+ * integer pointed to by the m argument should be prescaled by
+ * multiplying by DPLL_SCALE_FACTOR. The code will replace this with
+ * a non-scaled m upon return. This non-scaled m will result in a
+ * new_rate as close as possible to target_rate (but not greater than
+ * target_rate) given the current (parent_rate, n, prescaled m)
+ * triple. Returns DPLL_MULT_UNDERFLOW in the event that the
+ * non-scaled m attempted to underflow, which can allow the calling
+ * function to bail out early; or 0 upon success.
+ */
+static int _dpll_test_mult(int *m, int n, unsigned long *new_rate,
+ unsigned long target_rate,
+ unsigned long parent_rate)
+{
+ int r = 0, carry = 0;
+
+ /* Unscale m and round if necessary */
+ if (*m % DPLL_SCALE_FACTOR >= DPLL_ROUNDING_VAL)
+ carry = 1;
+ *m = (*m / DPLL_SCALE_FACTOR) + carry;
+
+ /*
+ * The new rate must be <= the target rate to avoid programming
+ * a rate that is impossible for the hardware to handle
+ */
+ *new_rate = _dpll_compute_new_rate(parent_rate, *m, n);
+ if (*new_rate > target_rate) {
+ (*m)--;
+ *new_rate = 0;
+ }
+
+ /* Guard against m underflow */
+ if (*m < DPLL_MIN_MULTIPLIER) {
+ *m = DPLL_MIN_MULTIPLIER;
+ *new_rate = 0;
+ r = DPLL_MULT_UNDERFLOW;
+ }
+
+ if (*new_rate == 0)
+ *new_rate = _dpll_compute_new_rate(parent_rate, *m, n);
+
+ return r;
+}
+
+/* Public functions */
+
+void omap2_init_dpll_parent(struct clk *clk)
+{
+ u32 v;
+ struct dpll_data *dd;
+
+ dd = clk->dpll_data;
+ if (!dd)
+ return;
+
+ /* Return bypass rate if DPLL is bypassed */
+ v = __raw_readl(dd->control_reg);
+ v &= dd->enable_mask;
+ v >>= __ffs(dd->enable_mask);
+
+ /* Reparent in case the dpll is in bypass */
+ if (cpu_is_omap24xx()) {
+ if (v == OMAP2XXX_EN_DPLL_LPBYPASS ||
+ v == OMAP2XXX_EN_DPLL_FRBYPASS)
+ clk_reparent(clk, dd->clk_bypass);
+ } else if (cpu_is_omap34xx()) {
+ if (v == OMAP3XXX_EN_DPLL_LPBYPASS ||
+ v == OMAP3XXX_EN_DPLL_FRBYPASS)
+ clk_reparent(clk, dd->clk_bypass);
+ } else if (cpu_is_omap44xx()) {
+ if (v == OMAP4XXX_EN_DPLL_LPBYPASS ||
+ v == OMAP4XXX_EN_DPLL_FRBYPASS ||
+ v == OMAP4XXX_EN_DPLL_MNBYPASS)
+ clk_reparent(clk, dd->clk_bypass);
+ }
+ return;
+}
+
+/**
+ * omap2_get_dpll_rate - returns the current DPLL CLKOUT rate
+ * @clk: struct clk * of a DPLL
+ *
+ * DPLLs can be locked or bypassed - basically, enabled or disabled.
+ * When locked, the DPLL output depends on the M and N values. When
+ * bypassed, on OMAP2xxx, the output rate is either the 32KiHz clock
+ * or sys_clk. Bypass rates on OMAP3 depend on the DPLL: DPLLs 1 and
+ * 2 are bypassed with dpll1_fclk and dpll2_fclk respectively
+ * (generated by DPLL3), while DPLL 3, 4, and 5 bypass rates are sys_clk.
+ * Returns the current DPLL CLKOUT rate (*not* CLKOUTX2) if the DPLL is
+ * locked, or the appropriate bypass rate if the DPLL is bypassed, or 0
+ * if the clock @clk is not a DPLL.
+ */
+u32 omap2_get_dpll_rate(struct clk *clk)
+{
+ long long dpll_clk;
+ u32 dpll_mult, dpll_div, v;
+ struct dpll_data *dd;
+
+ dd = clk->dpll_data;
+ if (!dd)
+ return 0;
+
+ /* Return bypass rate if DPLL is bypassed */
+ v = __raw_readl(dd->control_reg);
+ v &= dd->enable_mask;
+ v >>= __ffs(dd->enable_mask);
+
+ if (cpu_is_omap24xx()) {
+ if (v == OMAP2XXX_EN_DPLL_LPBYPASS ||
+ v == OMAP2XXX_EN_DPLL_FRBYPASS)
+ return dd->clk_bypass->rate;
+ } else if (cpu_is_omap34xx()) {
+ if (v == OMAP3XXX_EN_DPLL_LPBYPASS ||
+ v == OMAP3XXX_EN_DPLL_FRBYPASS)
+ return dd->clk_bypass->rate;
+ } else if (cpu_is_omap44xx()) {
+ if (v == OMAP4XXX_EN_DPLL_LPBYPASS ||
+ v == OMAP4XXX_EN_DPLL_FRBYPASS ||
+ v == OMAP4XXX_EN_DPLL_MNBYPASS)
+ return dd->clk_bypass->rate;
+ }
+
+ v = __raw_readl(dd->mult_div1_reg);
+ dpll_mult = v & dd->mult_mask;
+ dpll_mult >>= __ffs(dd->mult_mask);
+ dpll_div = v & dd->div1_mask;
+ dpll_div >>= __ffs(dd->div1_mask);
+
+ dpll_clk = (long long)dd->clk_ref->rate * dpll_mult;
+ do_div(dpll_clk, dpll_div + 1);
+
+ return dpll_clk;
+}
+
+/* DPLL rate rounding code */
+
+/**
+ * omap2_dpll_set_rate_tolerance: set the error tolerance during rate rounding
+ * @clk: struct clk * of the DPLL
+ * @tolerance: maximum rate error tolerance
+ *
+ * Set the maximum DPLL rate error tolerance for the rate rounding
+ * algorithm. The rate tolerance is an attempt to balance DPLL power
+ * saving (the least divider value "n") vs. rate fidelity (the least
+ * difference between the desired DPLL target rate and the rounded
+ * rate out of the algorithm). So, increasing the tolerance is likely
+ * to decrease DPLL power consumption and increase DPLL rate error.
+ * Returns -EINVAL if provided a null clock ptr or a clk that is not a
+ * DPLL; or 0 upon success.
+ */
+int omap2_dpll_set_rate_tolerance(struct clk *clk, unsigned int tolerance)
+{
+ if (!clk || !clk->dpll_data)
+ return -EINVAL;
+
+ clk->dpll_data->rate_tolerance = tolerance;
+
+ return 0;
+}
+
+/**
+ * omap2_dpll_round_rate - round a target rate for an OMAP DPLL
+ * @clk: struct clk * for a DPLL
+ * @target_rate: desired DPLL clock rate
+ *
+ * Given a DPLL, a desired target rate, and a rate tolerance, round
+ * the target rate to a possible, programmable rate for this DPLL.
+ * Rate tolerance is assumed to be set by the caller before this
+ * function is called. Attempts to select the minimum possible n
+ * within the tolerance to reduce power consumption. Stores the
+ * computed (m, n) in the DPLL's dpll_data structure so set_rate()
+ * will not need to call this (expensive) function again. Returns ~0
+ * if the target rate cannot be rounded, either because the rate is
+ * too low or because the rate tolerance is set too tightly; or the
+ * rounded rate upon success.
+ */
+long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate)
+{
+ int m, n, r, e, scaled_max_m;
+ unsigned long scaled_rt_rp, new_rate;
+ int min_e = -1, min_e_m = -1, min_e_n = -1;
+ struct dpll_data *dd;
+
+ if (!clk || !clk->dpll_data)
+ return ~0;
+
+ dd = clk->dpll_data;
+
+ pr_debug("clock: starting DPLL round_rate for clock %s, target rate "
+ "%ld\n", clk->name, target_rate);
+
+ scaled_rt_rp = target_rate / (dd->clk_ref->rate / DPLL_SCALE_FACTOR);
+ scaled_max_m = dd->max_multiplier * DPLL_SCALE_FACTOR;
+
+ dd->last_rounded_rate = 0;
+
+ for (n = dd->min_divider; n <= dd->max_divider; n++) {
+
+ /* Is the (input clk, divider) pair valid for the DPLL? */
+ r = _dpll_test_fint(clk, n);
+ if (r == DPLL_FINT_UNDERFLOW)
+ break;
+ else if (r == DPLL_FINT_INVALID)
+ continue;
+
+ /* Compute the scaled DPLL multiplier, based on the divider */
+ m = scaled_rt_rp * n;
+
+ /*
+ * Since we're counting n up, a m overflow means we
+ * can bail out completely (since as n increases in
+ * the next iteration, there's no way that m can
+ * increase beyond the current m)
+ */
+ if (m > scaled_max_m)
+ break;
+
+ r = _dpll_test_mult(&m, n, &new_rate, target_rate,
+ dd->clk_ref->rate);
+
+ /* m can't be set low enough for this n - try with a larger n */
+ if (r == DPLL_MULT_UNDERFLOW)
+ continue;
+
+ e = target_rate - new_rate;
+ pr_debug("clock: n = %d: m = %d: rate error is %d "
+ "(new_rate = %ld)\n", n, m, e, new_rate);
+
+ if (min_e == -1 ||
+ min_e >= (int)(abs(e) - dd->rate_tolerance)) {
+ min_e = e;
+ min_e_m = m;
+ min_e_n = n;
+
+ pr_debug("clock: found new least error %d\n", min_e);
+
+ /* We found good settings -- bail out now */
+ if (min_e <= dd->rate_tolerance)
+ break;
+ }
+ }
+
+ if (min_e < 0) {
+ pr_debug("clock: error: target rate or tolerance too low\n");
+ return ~0;
+ }
+
+ dd->last_rounded_m = min_e_m;
+ dd->last_rounded_n = min_e_n;
+ dd->last_rounded_rate = _dpll_compute_new_rate(dd->clk_ref->rate,
+ min_e_m, min_e_n);
+
+ pr_debug("clock: final least error: e = %d, m = %d, n = %d\n",
+ min_e, min_e_m, min_e_n);
+ pr_debug("clock: final rate: %ld (target rate: %ld)\n",
+ dd->last_rounded_rate, target_rate);
+
+ return dd->last_rounded_rate;
+}
+
#include <plat/clockdomain.h>
#include <plat/cpu.h>
#include <plat/prcm.h>
-#include <asm/div64.h>
-#include <plat/sdrc.h>
-#include "sdrc.h"
#include "clock.h"
#include "prm.h"
#include "prm-regbits-24xx.h"
#include "cm-regbits-24xx.h"
#include "cm-regbits-34xx.h"
-/* DPLL rate rounding: minimum DPLL multiplier, divider values */
-#define DPLL_MIN_MULTIPLIER 1
-#define DPLL_MIN_DIVIDER 1
-
-/* Possible error results from _dpll_test_mult */
-#define DPLL_MULT_UNDERFLOW -1
-
-/*
- * Scale factor to mitigate roundoff errors in DPLL rate rounding.
- * The higher the scale factor, the greater the risk of arithmetic overflow,
- * but the closer the rounded rate to the target rate. DPLL_SCALE_FACTOR
- * must be a power of DPLL_SCALE_BASE.
- */
-#define DPLL_SCALE_FACTOR 64
-#define DPLL_SCALE_BASE 2
-#define DPLL_ROUNDING_VAL ((DPLL_SCALE_BASE / 2) * \
- (DPLL_SCALE_FACTOR / DPLL_SCALE_BASE))
-
-/* DPLL valid Fint frequency band limits - from 34xx TRM Section 4.7.6.2 */
-#define DPLL_FINT_BAND1_MIN 750000
-#define DPLL_FINT_BAND1_MAX 2100000
-#define DPLL_FINT_BAND2_MIN 7500000
-#define DPLL_FINT_BAND2_MAX 21000000
-
-/* _dpll_test_fint() return codes */
-#define DPLL_FINT_UNDERFLOW -1
-#define DPLL_FINT_INVALID -2
-
u8 cpu_mask;
/*-------------------------------------------------------------------------
* OMAP2/3/4 specific clock functions
*-------------------------------------------------------------------------*/
-void omap2_init_dpll_parent(struct clk *clk)
-{
- u32 v;
- struct dpll_data *dd;
-
- dd = clk->dpll_data;
- if (!dd)
- return;
-
- /* Return bypass rate if DPLL is bypassed */
- v = __raw_readl(dd->control_reg);
- v &= dd->enable_mask;
- v >>= __ffs(dd->enable_mask);
-
- /* Reparent in case the dpll is in bypass */
- if (cpu_is_omap24xx()) {
- if (v == OMAP2XXX_EN_DPLL_LPBYPASS ||
- v == OMAP2XXX_EN_DPLL_FRBYPASS)
- clk_reparent(clk, dd->clk_bypass);
- } else if (cpu_is_omap34xx()) {
- if (v == OMAP3XXX_EN_DPLL_LPBYPASS ||
- v == OMAP3XXX_EN_DPLL_FRBYPASS)
- clk_reparent(clk, dd->clk_bypass);
- } else if (cpu_is_omap44xx()) {
- if (v == OMAP4XXX_EN_DPLL_LPBYPASS ||
- v == OMAP4XXX_EN_DPLL_FRBYPASS ||
- v == OMAP4XXX_EN_DPLL_MNBYPASS)
- clk_reparent(clk, dd->clk_bypass);
- }
- return;
-}
-
/**
* _omap2xxx_clk_commit - commit clock parent/rate changes in hardware
* @clk: struct clk *
prm_read_mod_reg(OMAP24XX_GR_MOD, OMAP2_PRCM_CLKCFG_CTRL_OFFSET);
}
-/*
- * _dpll_test_fint - test whether an Fint value is valid for the DPLL
- * @clk: DPLL struct clk to test
- * @n: divider value (N) to test
- *
- * Tests whether a particular divider @n will result in a valid DPLL
- * internal clock frequency Fint. See the 34xx TRM 4.7.6.2 "DPLL Jitter
- * Correction". Returns 0 if OK, -1 if the enclosing loop can terminate
- * (assuming that it is counting N upwards), or -2 if the enclosing loop
- * should skip to the next iteration (again assuming N is increasing).
- */
-static int _dpll_test_fint(struct clk *clk, u8 n)
-{
- struct dpll_data *dd;
- long fint;
- int ret = 0;
-
- dd = clk->dpll_data;
-
- /* DPLL divider must result in a valid jitter correction val */
- fint = clk->parent->rate / (n + 1);
- if (fint < DPLL_FINT_BAND1_MIN) {
-
- pr_debug("rejecting n=%d due to Fint failure, "
- "lowering max_divider\n", n);
- dd->max_divider = n;
- ret = DPLL_FINT_UNDERFLOW;
-
- } else if (fint > DPLL_FINT_BAND1_MAX &&
- fint < DPLL_FINT_BAND2_MIN) {
-
- pr_debug("rejecting n=%d due to Fint failure\n", n);
- ret = DPLL_FINT_INVALID;
-
- } else if (fint > DPLL_FINT_BAND2_MAX) {
-
- pr_debug("rejecting n=%d due to Fint failure, "
- "boosting min_divider\n", n);
- dd->min_divider = n;
- ret = DPLL_FINT_INVALID;
-
- }
-
- return ret;
-}
-
/**
* omap2_init_clk_clkdm - look up a clockdomain name, store pointer in clk
* @clk: OMAP clock struct ptr to use
return;
}
-/**
- * omap2_get_dpll_rate - returns the current DPLL CLKOUT rate
- * @clk: struct clk * of a DPLL
- *
- * DPLLs can be locked or bypassed - basically, enabled or disabled.
- * When locked, the DPLL output depends on the M and N values. When
- * bypassed, on OMAP2xxx, the output rate is either the 32KiHz clock
- * or sys_clk. Bypass rates on OMAP3 depend on the DPLL: DPLLs 1 and
- * 2 are bypassed with dpll1_fclk and dpll2_fclk respectively
- * (generated by DPLL3), while DPLL 3, 4, and 5 bypass rates are sys_clk.
- * Returns the current DPLL CLKOUT rate (*not* CLKOUTX2) if the DPLL is
- * locked, or the appropriate bypass rate if the DPLL is bypassed, or 0
- * if the clock @clk is not a DPLL.
- */
-u32 omap2_get_dpll_rate(struct clk *clk)
-{
- long long dpll_clk;
- u32 dpll_mult, dpll_div, v;
- struct dpll_data *dd;
-
- dd = clk->dpll_data;
- if (!dd)
- return 0;
-
- /* Return bypass rate if DPLL is bypassed */
- v = __raw_readl(dd->control_reg);
- v &= dd->enable_mask;
- v >>= __ffs(dd->enable_mask);
-
- if (cpu_is_omap24xx()) {
- if (v == OMAP2XXX_EN_DPLL_LPBYPASS ||
- v == OMAP2XXX_EN_DPLL_FRBYPASS)
- return dd->clk_bypass->rate;
- } else if (cpu_is_omap34xx()) {
- if (v == OMAP3XXX_EN_DPLL_LPBYPASS ||
- v == OMAP3XXX_EN_DPLL_FRBYPASS)
- return dd->clk_bypass->rate;
- } else if (cpu_is_omap44xx()) {
- if (v == OMAP4XXX_EN_DPLL_LPBYPASS ||
- v == OMAP4XXX_EN_DPLL_FRBYPASS ||
- v == OMAP4XXX_EN_DPLL_MNBYPASS)
- return dd->clk_bypass->rate;
- }
-
- v = __raw_readl(dd->mult_div1_reg);
- dpll_mult = v & dd->mult_mask;
- dpll_mult >>= __ffs(dd->mult_mask);
- dpll_div = v & dd->div1_mask;
- dpll_div >>= __ffs(dd->div1_mask);
-
- dpll_clk = (long long)dd->clk_ref->rate * dpll_mult;
- do_div(dpll_clk, dpll_div + 1);
-
- return dpll_clk;
-}
-
/**
* omap2_clk_dflt_find_companion - find companion clock to @clk
* @clk: struct clk * to find the companion clock of
return 0;
}
-/* DPLL rate rounding code */
-
-/**
- * omap2_dpll_set_rate_tolerance: set the error tolerance during rate rounding
- * @clk: struct clk * of the DPLL
- * @tolerance: maximum rate error tolerance
- *
- * Set the maximum DPLL rate error tolerance for the rate rounding
- * algorithm. The rate tolerance is an attempt to balance DPLL power
- * saving (the least divider value "n") vs. rate fidelity (the least
- * difference between the desired DPLL target rate and the rounded
- * rate out of the algorithm). So, increasing the tolerance is likely
- * to decrease DPLL power consumption and increase DPLL rate error.
- * Returns -EINVAL if provided a null clock ptr or a clk that is not a
- * DPLL; or 0 upon success.
- */
-int omap2_dpll_set_rate_tolerance(struct clk *clk, unsigned int tolerance)
-{
- if (!clk || !clk->dpll_data)
- return -EINVAL;
-
- clk->dpll_data->rate_tolerance = tolerance;
-
- return 0;
-}
-
-static unsigned long _dpll_compute_new_rate(unsigned long parent_rate,
- unsigned int m, unsigned int n)
-{
- unsigned long long num;
-
- num = (unsigned long long)parent_rate * m;
- do_div(num, n);
- return num;
-}
-
-/*
- * _dpll_test_mult - test a DPLL multiplier value
- * @m: pointer to the DPLL m (multiplier) value under test
- * @n: current DPLL n (divider) value under test
- * @new_rate: pointer to storage for the resulting rounded rate
- * @target_rate: the desired DPLL rate
- * @parent_rate: the DPLL's parent clock rate
- *
- * This code tests a DPLL multiplier value, ensuring that the
- * resulting rate will not be higher than the target_rate, and that
- * the multiplier value itself is valid for the DPLL. Initially, the
- * integer pointed to by the m argument should be prescaled by
- * multiplying by DPLL_SCALE_FACTOR. The code will replace this with
- * a non-scaled m upon return. This non-scaled m will result in a
- * new_rate as close as possible to target_rate (but not greater than
- * target_rate) given the current (parent_rate, n, prescaled m)
- * triple. Returns DPLL_MULT_UNDERFLOW in the event that the
- * non-scaled m attempted to underflow, which can allow the calling
- * function to bail out early; or 0 upon success.
- */
-static int _dpll_test_mult(int *m, int n, unsigned long *new_rate,
- unsigned long target_rate,
- unsigned long parent_rate)
-{
- int r = 0, carry = 0;
-
- /* Unscale m and round if necessary */
- if (*m % DPLL_SCALE_FACTOR >= DPLL_ROUNDING_VAL)
- carry = 1;
- *m = (*m / DPLL_SCALE_FACTOR) + carry;
-
- /*
- * The new rate must be <= the target rate to avoid programming
- * a rate that is impossible for the hardware to handle
- */
- *new_rate = _dpll_compute_new_rate(parent_rate, *m, n);
- if (*new_rate > target_rate) {
- (*m)--;
- *new_rate = 0;
- }
-
- /* Guard against m underflow */
- if (*m < DPLL_MIN_MULTIPLIER) {
- *m = DPLL_MIN_MULTIPLIER;
- *new_rate = 0;
- r = DPLL_MULT_UNDERFLOW;
- }
-
- if (*new_rate == 0)
- *new_rate = _dpll_compute_new_rate(parent_rate, *m, n);
-
- return r;
-}
-
-/**
- * omap2_dpll_round_rate - round a target rate for an OMAP DPLL
- * @clk: struct clk * for a DPLL
- * @target_rate: desired DPLL clock rate
- *
- * Given a DPLL, a desired target rate, and a rate tolerance, round
- * the target rate to a possible, programmable rate for this DPLL.
- * Rate tolerance is assumed to be set by the caller before this
- * function is called. Attempts to select the minimum possible n
- * within the tolerance to reduce power consumption. Stores the
- * computed (m, n) in the DPLL's dpll_data structure so set_rate()
- * will not need to call this (expensive) function again. Returns ~0
- * if the target rate cannot be rounded, either because the rate is
- * too low or because the rate tolerance is set too tightly; or the
- * rounded rate upon success.
- */
-long omap2_dpll_round_rate(struct clk *clk, unsigned long target_rate)
-{
- int m, n, r, e, scaled_max_m;
- unsigned long scaled_rt_rp, new_rate;
- int min_e = -1, min_e_m = -1, min_e_n = -1;
- struct dpll_data *dd;
-
- if (!clk || !clk->dpll_data)
- return ~0;
-
- dd = clk->dpll_data;
-
- pr_debug("clock: starting DPLL round_rate for clock %s, target rate "
- "%ld\n", clk->name, target_rate);
-
- scaled_rt_rp = target_rate / (dd->clk_ref->rate / DPLL_SCALE_FACTOR);
- scaled_max_m = dd->max_multiplier * DPLL_SCALE_FACTOR;
-
- dd->last_rounded_rate = 0;
-
- for (n = dd->min_divider; n <= dd->max_divider; n++) {
-
- /* Is the (input clk, divider) pair valid for the DPLL? */
- r = _dpll_test_fint(clk, n);
- if (r == DPLL_FINT_UNDERFLOW)
- break;
- else if (r == DPLL_FINT_INVALID)
- continue;
-
- /* Compute the scaled DPLL multiplier, based on the divider */
- m = scaled_rt_rp * n;
-
- /*
- * Since we're counting n up, a m overflow means we
- * can bail out completely (since as n increases in
- * the next iteration, there's no way that m can
- * increase beyond the current m)
- */
- if (m > scaled_max_m)
- break;
-
- r = _dpll_test_mult(&m, n, &new_rate, target_rate,
- dd->clk_ref->rate);
-
- /* m can't be set low enough for this n - try with a larger n */
- if (r == DPLL_MULT_UNDERFLOW)
- continue;
-
- e = target_rate - new_rate;
- pr_debug("clock: n = %d: m = %d: rate error is %d "
- "(new_rate = %ld)\n", n, m, e, new_rate);
-
- if (min_e == -1 ||
- min_e >= (int)(abs(e) - dd->rate_tolerance)) {
- min_e = e;
- min_e_m = m;
- min_e_n = n;
-
- pr_debug("clock: found new least error %d\n", min_e);
-
- /* We found good settings -- bail out now */
- if (min_e <= dd->rate_tolerance)
- break;
- }
- }
-
- if (min_e < 0) {
- pr_debug("clock: error: target rate or tolerance too low\n");
- return ~0;
- }
-
- dd->last_rounded_m = min_e_m;
- dd->last_rounded_n = min_e_n;
- dd->last_rounded_rate = _dpll_compute_new_rate(dd->clk_ref->rate,
- min_e_m, min_e_n);
-
- pr_debug("clock: final least error: e = %d, m = %d, n = %d\n",
- min_e, min_e_m, min_e_n);
- pr_debug("clock: final rate: %ld (target rate: %ld)\n",
- dd->last_rounded_rate, target_rate);
-
- return dd->last_rounded_rate;
-}
-
/*-------------------------------------------------------------------------
* Omap2 clock reset and init functions
*-------------------------------------------------------------------------*/
projects / GitHub / LineageOS / G12 / android_kernel_amlogic_linux-4.9.git / commitdiff