From 8fa938acb318378463987b04be083dc2467e0480 Mon Sep 17 00:00:00 2001 From: Nishanth Menon Date: Fri, 18 Jan 2013 19:52:35 +0000 Subject: PM / devfreq: exynos4_bus: honor RCU lock usage OPP pointers cannot be expected to be valid beyond the boundary of rcu_read_lock and rcu_read_unlock. Unfortunately, the current exynos4 busfreq driver does not honor the usage constraint and stores the OPP pointer in struct busfreq_data. This could potentially become invalid later such as: across devfreq opp change decisions, resulting in unpredictable behavior. To fix this, we introduce a busfreq specific busfreq_opp_info structure which is used to handle OPP information. OPP information is de-referenced to voltage and frequency pairs as needed into busfreq_opp_info structure and used as needed. Signed-off-by: Nishanth Menon Signed-off-by: Rafael J. Wysocki --- drivers/devfreq/exynos4_bus.c | 94 ++++++++++++++++++++++++++++++------------- 1 file changed, 67 insertions(+), 27 deletions(-) (limited to 'drivers/devfreq') diff --git a/drivers/devfreq/exynos4_bus.c b/drivers/devfreq/exynos4_bus.c index 80c745e8308..46d94e9e95b 100644 --- a/drivers/devfreq/exynos4_bus.c +++ b/drivers/devfreq/exynos4_bus.c @@ -73,6 +73,16 @@ enum busclk_level_idx { #define EX4210_LV_NUM (LV_2 + 1) #define EX4x12_LV_NUM (LV_4 + 1) +/** + * struct busfreq_opp_info - opp information for bus + * @rate: Frequency in hertz + * @volt: Voltage in microvolts corresponding to this OPP + */ +struct busfreq_opp_info { + unsigned long rate; + unsigned long volt; +}; + struct busfreq_data { enum exynos4_busf_type type; struct device *dev; @@ -80,7 +90,7 @@ struct busfreq_data { bool disabled; struct regulator *vdd_int; struct regulator *vdd_mif; /* Exynos4412/4212 only */ - struct opp *curr_opp; + struct busfreq_opp_info curr_oppinfo; struct exynos4_ppmu dmc[2]; struct notifier_block pm_notifier; @@ -296,13 +306,14 @@ static unsigned int exynos4x12_clkdiv_sclkip[][3] = { }; -static int exynos4210_set_busclk(struct busfreq_data *data, struct opp *opp) +static int exynos4210_set_busclk(struct busfreq_data *data, + struct busfreq_opp_info *oppi) { unsigned int index; unsigned int tmp; for (index = LV_0; index < EX4210_LV_NUM; index++) - if (opp_get_freq(opp) == exynos4210_busclk_table[index].clk) + if (oppi->rate == exynos4210_busclk_table[index].clk) break; if (index == EX4210_LV_NUM) @@ -361,13 +372,14 @@ static int exynos4210_set_busclk(struct busfreq_data *data, struct opp *opp) return 0; } -static int exynos4x12_set_busclk(struct busfreq_data *data, struct opp *opp) +static int exynos4x12_set_busclk(struct busfreq_data *data, + struct busfreq_opp_info *oppi) { unsigned int index; unsigned int tmp; for (index = LV_0; index < EX4x12_LV_NUM; index++) - if (opp_get_freq(opp) == exynos4x12_mifclk_table[index].clk) + if (oppi->rate == exynos4x12_mifclk_table[index].clk) break; if (index == EX4x12_LV_NUM) @@ -576,11 +588,12 @@ static int exynos4x12_get_intspec(unsigned long mifclk) return -EINVAL; } -static int exynos4_bus_setvolt(struct busfreq_data *data, struct opp *opp, - struct opp *oldopp) +static int exynos4_bus_setvolt(struct busfreq_data *data, + struct busfreq_opp_info *oppi, + struct busfreq_opp_info *oldoppi) { int err = 0, tmp; - unsigned long volt = opp_get_voltage(opp); + unsigned long volt = oppi->volt; switch (data->type) { case TYPE_BUSF_EXYNOS4210: @@ -595,11 +608,11 @@ static int exynos4_bus_setvolt(struct busfreq_data *data, struct opp *opp, if (err) break; - tmp = exynos4x12_get_intspec(opp_get_freq(opp)); + tmp = exynos4x12_get_intspec(oppi->rate); if (tmp < 0) { err = tmp; regulator_set_voltage(data->vdd_mif, - opp_get_voltage(oldopp), + oldoppi->volt, MAX_SAFEVOLT); break; } @@ -609,7 +622,7 @@ static int exynos4_bus_setvolt(struct busfreq_data *data, struct opp *opp, /* Try to recover */ if (err) regulator_set_voltage(data->vdd_mif, - opp_get_voltage(oldopp), + oldoppi->volt, MAX_SAFEVOLT); break; default: @@ -626,17 +639,26 @@ static int exynos4_bus_target(struct device *dev, unsigned long *_freq, struct platform_device *pdev = container_of(dev, struct platform_device, dev); struct busfreq_data *data = platform_get_drvdata(pdev); - struct opp *opp = devfreq_recommended_opp(dev, _freq, flags); - unsigned long freq = opp_get_freq(opp); - unsigned long old_freq = opp_get_freq(data->curr_opp); + struct opp *opp; + unsigned long freq; + unsigned long old_freq = data->curr_oppinfo.rate; + struct busfreq_opp_info new_oppinfo; - if (IS_ERR(opp)) + rcu_read_lock(); + opp = devfreq_recommended_opp(dev, _freq, flags); + if (IS_ERR(opp)) { + rcu_read_unlock(); return PTR_ERR(opp); + } + new_oppinfo.rate = opp_get_freq(opp); + new_oppinfo.volt = opp_get_voltage(opp); + rcu_read_unlock(); + freq = new_oppinfo.rate; if (old_freq == freq) return 0; - dev_dbg(dev, "targetting %lukHz %luuV\n", freq, opp_get_voltage(opp)); + dev_dbg(dev, "targetting %lukHz %luuV\n", freq, new_oppinfo.volt); mutex_lock(&data->lock); @@ -644,17 +666,18 @@ static int exynos4_bus_target(struct device *dev, unsigned long *_freq, goto out; if (old_freq < freq) - err = exynos4_bus_setvolt(data, opp, data->curr_opp); + err = exynos4_bus_setvolt(data, &new_oppinfo, + &data->curr_oppinfo); if (err) goto out; if (old_freq != freq) { switch (data->type) { case TYPE_BUSF_EXYNOS4210: - err = exynos4210_set_busclk(data, opp); + err = exynos4210_set_busclk(data, &new_oppinfo); break; case TYPE_BUSF_EXYNOS4x12: - err = exynos4x12_set_busclk(data, opp); + err = exynos4x12_set_busclk(data, &new_oppinfo); break; default: err = -EINVAL; @@ -664,11 +687,12 @@ static int exynos4_bus_target(struct device *dev, unsigned long *_freq, goto out; if (old_freq > freq) - err = exynos4_bus_setvolt(data, opp, data->curr_opp); + err = exynos4_bus_setvolt(data, &new_oppinfo, + &data->curr_oppinfo); if (err) goto out; - data->curr_opp = opp; + data->curr_oppinfo = new_oppinfo; out: mutex_unlock(&data->lock); return err; @@ -702,7 +726,7 @@ static int exynos4_bus_get_dev_status(struct device *dev, exynos4_read_ppmu(data); busier_dmc = exynos4_get_busier_dmc(data); - stat->current_frequency = opp_get_freq(data->curr_opp); + stat->current_frequency = data->curr_oppinfo.rate; if (busier_dmc) addr = S5P_VA_DMC1; @@ -933,6 +957,7 @@ static int exynos4_busfreq_pm_notifier_event(struct notifier_block *this, struct busfreq_data *data = container_of(this, struct busfreq_data, pm_notifier); struct opp *opp; + struct busfreq_opp_info new_oppinfo; unsigned long maxfreq = ULONG_MAX; int err = 0; @@ -943,18 +968,29 @@ static int exynos4_busfreq_pm_notifier_event(struct notifier_block *this, data->disabled = true; + rcu_read_lock(); opp = opp_find_freq_floor(data->dev, &maxfreq); + if (IS_ERR(opp)) { + rcu_read_unlock(); + dev_err(data->dev, "%s: unable to find a min freq\n", + __func__); + return PTR_ERR(opp); + } + new_oppinfo.rate = opp_get_freq(opp); + new_oppinfo.volt = opp_get_voltage(opp); + rcu_read_unlock(); - err = exynos4_bus_setvolt(data, opp, data->curr_opp); + err = exynos4_bus_setvolt(data, &new_oppinfo, + &data->curr_oppinfo); if (err) goto unlock; switch (data->type) { case TYPE_BUSF_EXYNOS4210: - err = exynos4210_set_busclk(data, opp); + err = exynos4210_set_busclk(data, &new_oppinfo); break; case TYPE_BUSF_EXYNOS4x12: - err = exynos4x12_set_busclk(data, opp); + err = exynos4x12_set_busclk(data, &new_oppinfo); break; default: err = -EINVAL; @@ -962,7 +998,7 @@ static int exynos4_busfreq_pm_notifier_event(struct notifier_block *this, if (err) goto unlock; - data->curr_opp = opp; + data->curr_oppinfo = new_oppinfo; unlock: mutex_unlock(&data->lock); if (err) @@ -1027,13 +1063,17 @@ static int exynos4_busfreq_probe(struct platform_device *pdev) } } + rcu_read_lock(); opp = opp_find_freq_floor(dev, &exynos4_devfreq_profile.initial_freq); if (IS_ERR(opp)) { + rcu_read_unlock(); dev_err(dev, "Invalid initial frequency %lu kHz.\n", exynos4_devfreq_profile.initial_freq); return PTR_ERR(opp); } - data->curr_opp = opp; + data->curr_oppinfo.rate = opp_get_freq(opp); + data->curr_oppinfo.volt = opp_get_voltage(opp); + rcu_read_unlock(); platform_set_drvdata(pdev, data); -- cgit v1.2.3-70-g09d2