[PATCH] ARM: OMAP3+: dpll: optimize noncore dpll locking logic

[Nishanth Menon]

From: Vikram Pandita <vikram.pandita at ti.com>

If the dpll is already locked, code can be optimized
to return much earlier than doing redundent set of lock mode
and wait on idlest.

Cc: Tony Lindgren <tony at atomide.com>
Cc: Jon Hunter <jon-hunter at ti.com>
Cc: Paul Walmsley <paul at pwsan.com>
Cc: Mike Turquette <mturquette at ti.com>
Cc: linux-omap at vger.kernel.org
Cc: linux-arm-kernel at lists.infradead.org

Signed-off-by: Vikram Pandita <vikram.pandita at ti.com>
---
 arch/arm/mach-omap2/dpll3xxx.c |   12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/arch/arm/mach-omap2/dpll3xxx.c b/arch/arm/mach-omap2/dpll3xxx.c
index fc56745..3cfd7c4 100644
--- a/arch/arm/mach-omap2/dpll3xxx.c
+++ b/arch/arm/mach-omap2/dpll3xxx.c
@@ -135,11 +135,20 @@ static u16 _omap3_dpll_compute_freqsel(struct clk *clk, u8 n)
  */
 static int _omap3_noncore_dpll_lock(struct clk *clk)
 {
+	const struct dpll_data *dd;
 	u8 ai;
-	int r;
+	u8 state = 1;
+	int r = 0;
 
 	pr_debug("clock: locking DPLL %s\n", clk->name);
 
+	dd = clk->dpll_data;
+	state <<= __ffs(dd->idlest_mask);
+
+	/* Check if already locked */
+	if ((__raw_readl(dd->idlest_reg) & dd->idlest_mask) == state)
+		goto done;
+
 	ai = omap3_dpll_autoidle_read(clk);
 
 	omap3_dpll_deny_idle(clk);
@@ -151,6 +160,7 @@ static int _omap3_noncore_dpll_lock(struct clk *clk)
 	if (ai)
 		omap3_dpll_allow_idle(clk);
 
+done:
 	return r;
 }
 
-- 
1.7.9.5