From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jean Pihet Subject: [PATCH 2/7] ARM: OMAP2+: PM: add a lock to protect the powerdomains next state Date: Wed, 12 Sep 2012 11:55:27 +0200 Message-ID: <1347443732-7411-3-git-send-email-j-pihet@ti.com> References: <1347443732-7411-1-git-send-email-j-pihet@ti.com> Return-path: Received: from mail-wg0-f44.google.com ([74.125.82.44]:65116 "EHLO mail-wg0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753445Ab2ILJzv (ORCPT ); Wed, 12 Sep 2012 05:55:51 -0400 Received: by wgbdr13 with SMTP id dr13so1350058wgb.1 for ; Wed, 12 Sep 2012 02:55:50 -0700 (PDT) In-Reply-To: <1347443732-7411-1-git-send-email-j-pihet@ti.com> Sender: linux-omap-owner@vger.kernel.org List-Id: linux-omap@vger.kernel.org To: linux-omap@vger.kernel.org, paul@pwsan.com, linux-arm-kernel@lists.infradead.org, khilman@ti.com, Benoit Cousson , Santosh Shilimkar , Nishanth Menon , Rajendra Nayak Cc: Jean Pihet pwrdm_set_fpwrst, pwrdm_set_next_fpwrst and pwrdm_read_next_fpwrst are intented to be the only API to program and request the next state of a power domain. This patch protects the power domain next state settings and structs from concurrent accesses by the use of a lock. A spinlock is used since the API functions can be called from atomic context (.i.e) either from cpuidle path or suspend path. [ambresh@ti.com: reported the atomic context issue and suggested to replace the initial mutex with a spinlock] Signed-off-by: Jean Pihet Reported-by: Ambresh K --- arch/arm/mach-omap2/powerdomain.c | 40 ++++++++++++++++++++++++++++++++---- arch/arm/mach-omap2/powerdomain.h | 3 ++ 2 files changed, 38 insertions(+), 5 deletions(-) diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c index 18c21fa..f4b219f 100644 --- a/arch/arm/mach-omap2/powerdomain.c +++ b/arch/arm/mach-omap2/powerdomain.c @@ -102,6 +102,7 @@ static int _pwrdm_register(struct powerdomain *pwrdm) INIT_LIST_HEAD(&pwrdm->voltdm_node); voltdm_add_pwrdm(voltdm, pwrdm); + spin_lock_init(&pwrdm->lock); list_add(&pwrdm->node, &pwrdm_list); /* Initialize the powerdomain's state counter */ @@ -394,6 +395,22 @@ static int _pwrdm_pwrst_to_fpwrst(struct powerdomain *pwrdm, u8 pwrst, u8 logic) } +/** + * _pwrdm_read_next_fpwrst - get next powerdomain functional power state + * @pwrdm: struct powerdomain * to get power state + * + * Return the powerdomain @pwrdm's next functional power state. + * Returns -EINVAL if the powerdomain pointer is null or returns + * the next power state upon success. + */ +static int _pwrdm_read_next_fpwrst(struct powerdomain *pwrdm) +{ + int next_pwrst = pwrdm_read_next_pwrst(pwrdm); + int next_logic = pwrdm_read_logic_retst(pwrdm); + + return _pwrdm_pwrst_to_fpwrst(pwrdm, next_pwrst, next_logic); +} + /* Public functions */ /** @@ -677,6 +694,7 @@ int pwrdm_set_fpwrst(struct powerdomain *pwrdm, enum pwrdm_func_state fpwrst) int pwrst = _pwrdm_fpwrst_to_pwrst(pwrdm, fpwrst); int logic = _pwrdm_fpwrst_to_logic_pwrst(pwrdm, fpwrst); int sleep_switch = -1, ret = 0, hwsup = 0; + unsigned long flags; if (!pwrdm || IS_ERR(pwrdm) || (pwrst < 0) || (logic < 0)) { pr_debug("%s: invalid params: pwrdm=%p, fpwrst=%0x\n", @@ -687,9 +705,11 @@ int pwrdm_set_fpwrst(struct powerdomain *pwrdm, enum pwrdm_func_state fpwrst) pr_debug("%s: set fpwrst %0x to pwrdm %s\n", __func__, fpwrst, pwrdm->name); - next_fpwrst = pwrdm_read_next_fpwrst(pwrdm); + spin_lock_irqsave(&pwrdm->lock, flags); + + next_fpwrst = _pwrdm_read_next_fpwrst(pwrdm); if (next_fpwrst == fpwrst) - return ret; + goto out; curr_pwrst = pwrdm_read_pwrst(pwrdm); if (curr_pwrst < PWRDM_POWER_ON) { @@ -725,6 +745,8 @@ int pwrdm_set_fpwrst(struct powerdomain *pwrdm, enum pwrdm_func_state fpwrst) break; } +out: + spin_unlock_irqrestore(&pwrdm->lock, flags); return ret; } @@ -741,6 +763,7 @@ int pwrdm_set_next_fpwrst(struct powerdomain *pwrdm, int pwrst = _pwrdm_fpwrst_to_pwrst(pwrdm, fpwrst); int logic = _pwrdm_fpwrst_to_logic_pwrst(pwrdm, fpwrst); int ret = 0; + unsigned long flags; if (!pwrdm || IS_ERR(pwrdm) || (pwrst < 0) || (logic < 0)) { pr_debug("%s: invalid params: pwrdm=%p, fpwrst=%0x\n", @@ -751,6 +774,8 @@ int pwrdm_set_next_fpwrst(struct powerdomain *pwrdm, pr_debug("%s: set fpwrst %0x to pwrdm %s\n", __func__, fpwrst, pwrdm->name); + spin_lock_irqsave(&pwrdm->lock, flags); + ret = pwrdm_set_logic_retst(pwrdm, logic); if (ret) pr_err("%s: unable to set logic state %0x of powerdomain: %s\n", @@ -761,6 +786,7 @@ int pwrdm_set_next_fpwrst(struct powerdomain *pwrdm, pr_err("%s: unable to set power state %0x of powerdomain: %s\n", __func__, pwrst, pwrdm->name); + spin_unlock_irqrestore(&pwrdm->lock, flags); return ret; }; @@ -837,10 +863,14 @@ int pwrdm_read_next_pwrst(struct powerdomain *pwrdm) */ int pwrdm_read_next_fpwrst(struct powerdomain *pwrdm) { - int next_pwrst = pwrdm_read_next_pwrst(pwrdm); - int next_logic = pwrdm_read_logic_retst(pwrdm); + int ret; + unsigned long flags; - return _pwrdm_pwrst_to_fpwrst(pwrdm, next_pwrst, next_logic); + spin_lock_irqsave(&pwrdm->lock, flags); + ret = _pwrdm_read_next_fpwrst(pwrdm); + spin_unlock_irqrestore(&pwrdm->lock, flags); + + return ret; } /** diff --git a/arch/arm/mach-omap2/powerdomain.h b/arch/arm/mach-omap2/powerdomain.h index aa5de4f..c3dc363 100644 --- a/arch/arm/mach-omap2/powerdomain.h +++ b/arch/arm/mach-omap2/powerdomain.h @@ -17,6 +17,7 @@ #include #include +#include #include #include @@ -109,6 +110,7 @@ struct powerdomain; * @pwrdm_clkdms: Clockdomains in this powerdomain * @node: list_head linking all powerdomains * @voltdm_node: list_head linking all powerdomains in a voltagedomain + * @lock: powerdomain next state registers protection lock * @pwrstctrl_offs: (AM33XX only) XXX_PWRSTCTRL reg offset from prcm_offs * @pwrstst_offs: (AM33XX only) XXX_PWRSTST reg offset from prcm_offs * @logicretstate_mask: (AM33XX only) mask for logic retention bitfield @@ -142,6 +144,7 @@ struct powerdomain { struct clockdomain *pwrdm_clkdms[PWRDM_MAX_CLKDMS]; struct list_head node; struct list_head voltdm_node; + spinlock_t lock; int state; unsigned state_counter[PWRDM_MAX_PWRSTS]; unsigned ret_logic_off_counter; -- 1.7.7.6