linux/arch/arm/mach-omap2/clockdomains2xxx_3xxx_data.c

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/*
* OMAP2/3 clockdomain common data
*
* Copyright (C) 2008-2011 Texas Instruments, Inc.
* Copyright (C) 2008-2010 Nokia Corporation
*
* Paul Walmsley, Jouni Högander
*
* This file contains clockdomains and clockdomain wakeup/sleep
* dependencies for the OMAP2/3 chips. Some notes:
*
* A useful validation rule for struct clockdomain: Any clockdomain
* referenced by a wkdep_srcs or sleepdep_srcs array must have a
* dep_bit assigned. So wkdep_srcs/sleepdep_srcs are really just
* software-controllable dependencies. Non-software-controllable
* dependencies do exist, but they are not encoded below (yet).
*
* 24xx does not support programmable sleep dependencies (SLEEPDEP)
*
* The overly-specific dep_bit names are due to a bit name collision
* with CM_FCLKEN_{DSP,IVA2}. The DSP/IVA2 PM_WKDEP and CM_SLEEPDEP shift
* value are the same for all powerdomains: 2
*
* XXX should dep_bit be a mask, so we can test to see if it is 0 as a
* sanity check?
* XXX encode hardware fixed wakeup dependencies -- esp. for 3430 CORE
*/
/*
* To-Do List
* -> Port the Sleep/Wakeup dependencies for the domains
* from the Power domain framework
*/
#include <linux/kernel.h>
#include <linux/io.h>
#include "clockdomain.h"
#include "prm2xxx_3xxx.h"
#include "cm2xxx_3xxx.h"
#include "cm-regbits-24xx.h"
#include "cm-regbits-34xx.h"
#include "cm-regbits-44xx.h"
#include "prm-regbits-24xx.h"
#include "prm-regbits-34xx.h"
/*
* Clockdomain dependencies for wkdeps/sleepdeps
*
* XXX Hardware dependencies (e.g., dependencies that cannot be
* changed in software) are not included here yet, but should be.
*/
/* Wakeup dependency source arrays */
/* 2xxx-specific possible dependencies */
/* 2xxx PM_WKDEP_GFX: CORE, MPU, WKUP */
struct clkdm_dep gfx_24xx_wkdeps[] = {
{ .clkdm_name = "core_l3_clkdm" },
{ .clkdm_name = "core_l4_clkdm" },
{ .clkdm_name = "mpu_clkdm" },
{ .clkdm_name = "wkup_clkdm" },
{ NULL },
};
/* 2xxx PM_WKDEP_DSP: CORE, MPU, WKUP */
struct clkdm_dep dsp_24xx_wkdeps[] = {
{ .clkdm_name = "core_l3_clkdm" },
{ .clkdm_name = "core_l4_clkdm" },
{ .clkdm_name = "mpu_clkdm" },
{ .clkdm_name = "wkup_clkdm" },
{ NULL },
};
/*
* OMAP2/3-common clockdomains
*
* Even though the 2420 has a single PRCM module from the
* interconnect's perspective, internally it does appear to have
* separate PRM and CM clockdomains. The usual test case is
* sys_clkout/sys_clkout2.
*/
/* This is an implicit clockdomain - it is never defined as such in TRM */
struct clockdomain wkup_common_clkdm = {
.name = "wkup_clkdm",
.pwrdm = { .name = "wkup_pwrdm" },
.dep_bit = OMAP_EN_WKUP_SHIFT,
ARM: OMAP2+: hwmod code/clockdomain data: fix 32K sync timer Kevin discovered that commit c8d82ff68fb6873691536cf33021977efbf5593c ("ARM: OMAP2/3: hwmod data: Add 32k-sync timer data to hwmod database") broke CORE idle on OMAP3. This prevents device low power states. The root cause is that the 32K sync timer IP block does not support smart-idle mode[1], and so the hwmod code keeps the IP block in no-idle mode while it is active. This in turn prevents the WKUP clockdomain from transitioning to idle. There is a hardcoded sleep dependency that prevents the CORE_L3 and CORE_CM clockdomains from transitioning to idle when the WKUP clockdomain is active[2], so the chip cannot enter any device low power states. It turns out that there is no need to take the 32k sync timer out of idle. The IP block itself probably does not have any native idle handling at all, due to its simplicity. Furthermore, the PRCM will never request target idle for this IP block while the kernel is running, due to the sleep dependency that prevents the WKUP clockdomain from idling while the CORE_L3 clockdomain is active. So we can safely leave the 32k sync timer in target-force-idle mode, even while we continue to access it. This workaround is implemented by defining a new clockdomain flag, CLKDM_ACTIVE_WITH_MPU, that indicates that the clockdomain is guaranteed to be active whenever the MPU is inactive. If an IP block's main functional clock exists inside this clockdomain, and the IP block does not support smart-idle modes, then the hwmod code will place the IP block into target force-idle mode even when enabled. The WKUP clockdomains on OMAP3/4 are marked with this flag. (On OMAP2xxx, no OCP header existed on the 32k sync timer.) Other clockdomains also should be marked with this flag, but those changes are deferred until a later merge window, to create a minimal fix. Another theoretically clean fix for this problem would be to implement PM runtime-based control for 32k sync timer accesses. These PM runtime calls would need to located in a custom clocksource, since the 32k sync timer is currently used as an MMIO clocksource. But in practice, there would be little benefit to doing so; and there would be some cost, due to the addition of unnecessary lines of code and the additional CPU overhead of the PM runtime and hwmod code - unnecessary in this case. Another possible fix would have been to modify the pm34xx.c code to force the IP block idle before entering WFI. But this would not have been an acceptable approach: we are trying to remove this type of centralized IP block idle control from the PM code. This patch is a collaboration between Kevin Hilman <khilman@ti.com> and Paul Walmsley <paul@pwsan.com>. Thanks to Vaibhav Hiremath <hvaibhav@ti.com> for providing comments on an earlier version of this patch. Thanks to Tero Kristo <t-kristo@ti.com> for identifying a bug in an earlier version of this patch. Thanks to Benoît Cousson <b-cousson@ti.com> for identifying some bugs in several versions of this patch and for implementation comments. References: 1. Table 16-96 "REG_32KSYNCNT_SYSCONFIG" of the OMAP34xx TRM Rev. ZU (SWPU223U), available from: http://www.ti.com/pdfs/wtbu/OMAP34x_ES3.1.x_PUBLIC_TRM_vzU.zip 2. Table 4-72 "Sleep Dependencies" of the OMAP34xx TRM Rev. ZU (SWPU223U) 3. ibid. Cc: Tony Lindgren <tony@atomide.com> Cc: Vaibhav Hiremath <hvaibhav@ti.com> Cc: Benoît Cousson <b-cousson@ti.com> Cc: Tero Kristo <t-kristo@ti.com> Tested-by: Kevin Hilman <khilman@ti.com> Signed-off-by: Paul Walmsley <paul@pwsan.com> Signed-off-by: Kevin Hilman <khilman@ti.com>
2012-07-04 11:22:53 +00:00
.flags = CLKDM_ACTIVE_WITH_MPU,
};