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

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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: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
This commit is contained in:
Tero Kristo 2015-11-30 16:43:25 +02:00 committed by Stephen Boyd
parent cf81a1cf71
commit 07ff73a932
3 changed files with 29 additions and 1 deletions
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4
arch/arm/mach-omap2/clock.c
View File

@ -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);
}

25
drivers/clk/ti/dpll3xxx.c
View File

@ -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;
}

1
include/linux/clk/ti.h
View File

@ -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);