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authorPaul Walmsley <paul@pwsan.com>2009-01-28 12:27:42 -0700
committerRussell King <rmk+kernel@arm.linux.org.uk>2009-02-08 17:50:40 +0000
commit0eafd4725cf5d828e76e474b8991a228bbdd3f2b (patch)
tree797186618cb16d1ddb3f42a1ac9c9d4f84bdc7c1 /arch/arm/mach-omap2/clock34xx.c
parent87246b7567f7d1951bfcea29875523ef435c0ebf (diff)
[ARM] OMAP3 clock: add omap3_core_dpll_m2_set_rate()
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). linux-omap source commit is 7f8b2b0f4fe52238c67d79dedcd2794dcef4dddd. Signed-off-by: Paul Walmsley <paul@pwsan.com> Signed-off-by: Tony Lindgren <tony@atomide.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Diffstat (limited to 'arch/arm/mach-omap2/clock34xx.c')
-rw-r--r--arch/arm/mach-omap2/clock34xx.c65
1 files changed, 65 insertions, 0 deletions
diff --git a/arch/arm/mach-omap2/clock34xx.c b/arch/arm/mach-omap2/clock34xx.c
index 52385b1506e..1ad0a1359cb 100644
--- a/arch/arm/mach-omap2/clock34xx.c
+++ b/arch/arm/mach-omap2/clock34xx.c
@@ -634,6 +634,71 @@ static int omap3_dpll4_set_rate(struct clk *clk, unsigned long rate)
return omap3_noncore_dpll_set_rate(clk, rate);
}
+
+/*
+ * 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;
+}
+
+
static const struct clkops clkops_noncore_dpll_ops = {
.enable = &omap3_noncore_dpll_enable,
.disable = &omap3_noncore_dpll_disable,