From 98c342a584a2c61d5dfca7042f4a8394386b9eef Mon Sep 17 00:00:00 2001 From: Ranjani Vaidyanathan Date: Thu, 30 Aug 2012 15:02:32 -0500 Subject: [PATCH] ENGR00222134 MX6x - Fix race-conditions in low power code. Fix couple of race-conditions associated with low power IDLE code: 1. Ensure that bus freq mutex is used in the suspend/resume function 2. Ensure that the usecount of pll2 is incremented/decremented when ARM is switched to run from PLL2_PFD_400. And PLL2 is enabled/disabled when necessary. Signed-off-by: Ranjani Vaidyanathan --- arch/arm/mach-mx6/bus_freq.c | 4 ++++ arch/arm/mach-mx6/clock.c | 25 +++++++++++++++++++++---- arch/arm/mach-mx6/clock_mx6sl.c | 25 +++++++++++++++++++++---- 3 files changed, 46 insertions(+), 8 deletions(-) diff --git a/arch/arm/mach-mx6/bus_freq.c b/arch/arm/mach-mx6/bus_freq.c index 23f56d5deaf1..151b4ee27eb6 100644 --- a/arch/arm/mach-mx6/bus_freq.c +++ b/arch/arm/mach-mx6/bus_freq.c @@ -501,6 +501,8 @@ static int busfreq_suspend(struct platform_device *pdev, pm_message_t message) static int bus_freq_pm_notify(struct notifier_block *nb, unsigned long event, void *dummy) { + mutex_lock(&bus_freq_mutex); + if (event == PM_SUSPEND_PREPARE) { set_high_bus_freq(1); busfreq_suspended = 1; @@ -508,6 +510,8 @@ static int bus_freq_pm_notify(struct notifier_block *nb, unsigned long event, busfreq_suspended = 0; } + mutex_unlock(&bus_freq_mutex); + return NOTIFY_OK; } static int busfreq_resume(struct platform_device *pdev) diff --git a/arch/arm/mach-mx6/clock.c b/arch/arm/mach-mx6/clock.c index c2bf20177909..8b75aee78964 100644 --- a/arch/arm/mach-mx6/clock.c +++ b/arch/arm/mach-mx6/clock.c @@ -1261,7 +1261,16 @@ static int _clk_arm_set_rate(struct clk *clk, unsigned long rate) * PLL2_PFD_400M. */ if (pll1_sw_clk.parent != &pll2_pfd_400M) { - pll2_pfd_400M.enable(&pll2_pfd_400M); + if (pll2_pfd_400M.usecount == 0) { + /* Check if PLL2 needs to be enabled also. */ + if (pll2_528_bus_main_clk.usecount == 0) + pll2_528_bus_main_clk.enable(&pll2_528_bus_main_clk); + /* Ensure parent usecount is + * also incremented. + */ + pll2_528_bus_main_clk.usecount++; + pll2_pfd_400M.enable(&pll2_pfd_400M); + } pll2_pfd_400M.usecount++; arm_needs_pll2_400 = true; pll1_sw_clk.set_parent(&pll1_sw_clk, &pll2_pfd_400M); @@ -1288,11 +1297,19 @@ static int _clk_arm_set_rate(struct clk *clk, unsigned long rate) /* Make sure pll1_sw_clk is from pll1_sys_main_clk */ pll1_sw_clk.set_parent(&pll1_sw_clk, &pll1_sys_main_clk); pll1_sw_clk.parent = &pll1_sys_main_clk; - if (arm_needs_pll2_400) + if (arm_needs_pll2_400) { pll2_pfd_400M.usecount--; + if (pll2_pfd_400M.usecount == 0) { + pll2_pfd_400M.disable(&pll2_pfd_400M); + /* Ensure parent usecount is + * also decremented. + */ + pll2_528_bus_main_clk.usecount--; + if (pll2_528_bus_main_clk.usecount == 0) + pll2_528_bus_main_clk.disable(&pll2_528_bus_main_clk); + } + } arm_needs_pll2_400 = false; - if (pll2_pfd_400M.usecount == 0) - pll2_pfd_400M.disable(&pll2_pfd_400M); } parent_rate = clk_get_rate(clk->parent); div = parent_rate / rate; diff --git a/arch/arm/mach-mx6/clock_mx6sl.c b/arch/arm/mach-mx6/clock_mx6sl.c index 43b2bd1baac2..6bd818ae7139 100755 --- a/arch/arm/mach-mx6/clock_mx6sl.c +++ b/arch/arm/mach-mx6/clock_mx6sl.c @@ -1167,7 +1167,16 @@ static int _clk_arm_set_rate(struct clk *clk, unsigned long rate) * PLL2_PFD2_400M. */ if (pll1_sw_clk.parent != &pll2_pfd2_400M) { - pll2_pfd2_400M.enable(&pll2_pfd2_400M); + if (pll2_pfd2_400M.usecount == 0) { + /* Check if PLL2 needs to be enabled also. */ + if (pll2_528_bus_main_clk.usecount == 0) + pll2_528_bus_main_clk.enable(&pll2_528_bus_main_clk); + /* Ensure parent usecount is + * also incremented. + */ + pll2_528_bus_main_clk.usecount++; + pll2_pfd2_400M.enable(&pll2_pfd2_400M); + } arm_needs_pll2_400 = true; pll2_pfd2_400M.usecount++; pll1_sw_clk.set_parent(&pll1_sw_clk, &pll2_pfd2_400M); @@ -1192,11 +1201,19 @@ static int _clk_arm_set_rate(struct clk *clk, unsigned long rate) pll1_sw_clk.set_parent(&pll1_sw_clk, &pll1_sys_main_clk); pll1_sw_clk.parent = &pll1_sys_main_clk; - if (arm_needs_pll2_400) + if (arm_needs_pll2_400) { pll2_pfd2_400M.usecount--; + if (pll2_pfd2_400M.usecount == 0) { + pll2_pfd2_400M.disable(&pll2_pfd2_400M); + /* Ensure parent usecount is + * also decremented. + */ + pll2_528_bus_main_clk.usecount--; + if (pll2_528_bus_main_clk.usecount == 0) + pll2_528_bus_main_clk.disable(&pll2_528_bus_main_clk); + } + } arm_needs_pll2_400 = false; - if (pll2_pfd2_400M.usecount == 0) - pll2_pfd2_400M.disable(&pll2_pfd2_400M); } parent_rate = clk_get_rate(clk->parent); div = parent_rate / rate; -- 2.39.5