[PATCH 9/9] OMAP3 clock: add omap3_core_dpll_m2_set_rate()

Paul Walmsley
2008-07-08T02:56:38Z

Add the omap3_core_dpll_m2_set_rate() function to the OMAP3 clock code,
which calls into the SRAM function omap3_sram_configure_core_dpll() to
change the CORE DPLL M2 divider. (SRAM code is necessary since rate changes
on clocks upstream from the SDRC can glitch SDRAM accesses.)

Use this function for the set_rate function pointer in the dpll3_m2_ck
struct clk. With this function in place, PM/OPP code should be able to
alter SDRAM speed via code similar to:

clk_set_rate(&dpll3_m2_ck, target_rate).

Signed-off-by: Paul Walmsley <paul@pwsan.com>
---

arch/arm/mach-omap2/clock34xx.c | 66 ++++++++++++++++++++++++++++++++++++++-
arch/arm/mach-omap2/clock34xx.h | 9 ++---
2 files changed, 69 insertions(+), 6 deletions(-)

diff --git a/arch/arm/mach-omap2/clock34xx.c b/arch/arm/mach-omap2/clock34xx.c
index 482f05c..0caa4dd 100644
--- a/arch/arm/mach-omap2/clock34xx.c
+++ b/arch/arm/mach-omap2/clock34xx.c
@@ -15,7 +15,6 @@
* published by the Free Software Foundation.
*/
#undef DEBUG
-#define DEBUG

#include <linux/module.h>
#include <linux/kernel.h>
@@ -410,6 +409,71 @@ static int omap3_noncore_dpll_set_rate(struct clk *clk, unsigned long rate)
return 0;
}

+
+/*
+ * CORE DPLL (DPLL3) rate programming functions
+ *
+ * These call into SRAM code to do the actual CM writes, since the SDRAM
+ * is clocked from DPLL3.
+ */
+
+/**
+ * omap3_core_dpll_m2_set_rate - set CORE DPLL M2 divider
+ * @clk: struct clk * of DPLL to set
+ * @rate: rounded target rate
+ *
+ * Program the DPLL M2 divider with the rounded target rate. Returns
+ * -EINVAL upon error, or 0 upon success.
+ */
+static int omap3_core_dpll_m2_set_rate(struct clk *clk, unsigned long rate)
+{
+ u32 new_div = 0;
+ unsigned long validrate, sdrcrate;
+ struct omap_sdrc_params *sp;
+
+ if (!clk || !rate)
+ return -EINVAL;
+
+ if (clk != &dpll3_m2_ck)
+ return -EINVAL;
+
+ if (rate == clk->rate)
+ return 0;
+
+ validrate = omap2_clksel_round_rate_div(clk, rate, &new_div);
+ if (validrate != rate)
+ return -EINVAL;
+
+ sdrcrate = sdrc_ick.rate;
+ if (rate > clk->rate)
+ sdrcrate <<= ((rate / clk->rate) - 1);
+ else
+ sdrcrate >>= ((clk->rate / rate) - 1);
+
+ sp = omap2_sdrc_get_params(sdrcrate);
+ if (!sp)
+ return -EINVAL;
+
+ pr_info("clock: changing CORE DPLL rate from %lu to %lu\n", clk->rate,
+ validrate);
+ pr_info("clock: SDRC timing params used: %08x %08x %08x\n",
+ sp->rfr_ctrl, sp->actim_ctrla, sp->actim_ctrlb);
+
+ /* REVISIT: SRAM code doesn't support other M2 divisors yet */
+ WARN_ON(new_div != 1 && new_div != 2);
+
+ /* REVISIT: Add SDRC_MR changing to this code also */
+ local_irq_disable();
+ omap3_configure_core_dpll(sp->rfr_ctrl, sp->actim_ctrla,
+ sp->actim_ctrlb, new_div);
+ local_irq_enable();
+
+ omap2_clksel_recalc(clk);
+
+ return 0;
+}
+
+
/* DPLL autoidle read/set code */

diff --git a/arch/arm/mach-omap2/clock34xx.h b/arch/arm/mach-omap2/clock34xx.h
index 161da12..74a7e98 100644
--- a/arch/arm/mach-omap2/clock34xx.h
+++ b/arch/arm/mach-omap2/clock34xx.h
@@ -35,6 +35,7 @@ static u32 omap3_dpll_autoidle_read(struct clk *clk);
static int omap3_noncore_dpll_enable(struct clk *clk);
static void omap3_noncore_dpll_disable(struct clk *clk);
static int omap3_noncore_dpll_set_rate(struct clk *clk, unsigned long rate);
+static int omap3_core_dpll_m2_set_rate(struct clk *clk, unsigned long rate);

/* Maximum DPLL multiplier, divider values for OMAP3 */
#define OMAP3_MAX_DPLL_MULT 2048
@@ -481,11 +482,7 @@ static const struct clksel div31_dpll3m2_clksel[] = {
{ .parent = NULL }
};

-/*
- * DPLL3 output M2
- * REVISIT: This DPLL output divider must be changed in SRAM, so until
- * that code is ready, this should remain a 'read-only' clksel clock.
- */
+/* DPLL3 output M2 - primary control point for CORE speed */
static struct clk dpll3_m2_ck = {
.name = "dpll3_m2_ck",
.parent = &dpll3_ck,
@@ -495,6 +492,8 @@ static struct clk dpll3_m2_ck = {
.clksel = div31_dpll3m2_clksel,
.flags = CLOCK_IN_OMAP343X | RATE_PROPAGATES |
PARENT_CONTROLS_CLOCK,
+ .round_rate = &omap2_clksel_round_rate,
+ .set_rate = &omap3_core_dpll_m2_set_rate,
.recalc = &omap2_clksel_recalc,
};