Commit 07ff73a9 authored by Tero Kristo's avatar Tero Kristo Committed by Stephen Boyd
Browse files

clk: ti: omap5+: dpll: implement errata i810 



Errata i810 states that DPLL controller can get stuck while transitioning
to a power saving state, while its M/N ratio is being re-programmed.

As a workaround, before re-programming the M/N ratio, SW has to ensure
the DPLL cannot start an idle state transition. SW can disable DPLL
idling by setting the DPLL AUTO_DPLL_MODE=0 or keeping a clock request
active by setting a dependent clock domain in SW_WKUP.

This errata impacts OMAP5 and DRA7 chips, so enable the errata for these.

Signed-off-by: default avatarTero Kristo <t-kristo@ti.com>
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
parent cf81a1cf

arch/arm/mach-omap2/clock.c

+4 −0
Original line number Diff line number Diff line
@@ -225,5 +225,9 @@ void __init ti_clk_init_features(void) 
	if (omap_rev() == OMAP3430_REV_ES1_0)

		features.flags |= TI_CLK_DPLL4_DENY_REPROGRAM;



	/* Errata I810 for omap5 / dra7 */

	if (soc_is_omap54xx() || soc_is_dra7xx())

		features.flags |= TI_CLK_ERRATA_I810;



	ti_clk_setup_features(&features);

}

drivers/clk/ti/dpll3xxx.c

+24 −1
Original line number Diff line number Diff line
@@ -305,8 +305,9 @@ static void _lookup_sddiv(struct clk_hw_omap *clk, u8 *sd_div, u16 m, u8 n) 
static int omap3_noncore_dpll_program(struct clk_hw_omap *clk, u16 freqsel)

{

	struct dpll_data *dd = clk->dpll_data;

	u8 dco, sd_div;

	u8 dco, sd_div, ai = 0;

	u32 v;

	bool errata_i810;



	/* 3430 ES2 TRM: 4.7.6.9 DPLL Programming Sequence */

	_omap3_noncore_dpll_bypass(clk);
@@ -350,6 +351,25 @@ static int omap3_noncore_dpll_program(struct clk_hw_omap *clk, u16 freqsel) 
		v |= sd_div << __ffs(dd->sddiv_mask);

	}



	/*

	 * Errata i810 - DPLL controller can get stuck while transitioning

	 * to a power saving state. Software must ensure the DPLL can not

	 * transition to a low power state while changing M/N values.

	 * Easiest way to accomplish this is to prevent DPLL autoidle

	 * before doing the M/N re-program.

	 */

	errata_i810 = ti_clk_get_features()->flags & TI_CLK_ERRATA_I810;



	if (errata_i810) {

		ai = omap3_dpll_autoidle_read(clk);

		if (ai) {

			omap3_dpll_deny_idle(clk);



			/* OCP barrier */

			omap3_dpll_autoidle_read(clk);

		}

	}



	ti_clk_ll_ops->clk_writel(v, dd->mult_div1_reg);



	/* Set 4X multiplier and low-power mode */
@@ -379,6 +399,9 @@ static int omap3_noncore_dpll_program(struct clk_hw_omap *clk, u16 freqsel) 


	_omap3_noncore_dpll_lock(clk);



	if (errata_i810 && ai)

		omap3_dpll_allow_idle(clk);



	return 0;

}

include/linux/clk/ti.h

+1 −0
Original line number Diff line number Diff line
@@ -286,6 +286,7 @@ struct ti_clk_features { 
#define TI_CLK_DPLL_HAS_FREQSEL			BIT(0)

#define TI_CLK_DPLL4_DENY_REPROGRAM		BIT(1)

#define TI_CLK_DISABLE_CLKDM_CONTROL		BIT(2)

#define TI_CLK_ERRATA_I810			BIT(3)



void ti_clk_setup_features(struct ti_clk_features *features);

const struct ti_clk_features *ti_clk_get_features(void);

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