From a1a8e1dc111d6f05e7164e851e58219d428359e1 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Tue, 16 Jul 2013 15:28:00 +0100 Subject: [PATCH 1/3] iio:trigger: Fix use_count race condition When using more than one trigger consumer it can happen that multiple threads perform a read-modify-update cycle on 'use_count' concurrently. This can cause updates to be lost and use_count can get stuck at non-zero value, in which case the IIO core assumes that at least one thread is still running and will wait for it to finish before running any trigger handlers again. This effectively renders the trigger disabled and a reboot is necessary before it can be used again. To fix this make use_count an atomic variable. Also set it to the number of consumers before starting the first consumer, otherwise it might happen that use_count drops to 0 even though not all consumers have been run yet. Signed-off-by: Lars-Peter Clausen Tested-by: Denis Ciocca Signed-off-by: Jonathan Cameron --- drivers/iio/industrialio-trigger.c | 34 +++++++++++++++++++----------- include/linux/iio/trigger.h | 3 ++- 2 files changed, 24 insertions(+), 13 deletions(-) diff --git a/drivers/iio/industrialio-trigger.c b/drivers/iio/industrialio-trigger.c index ea8a4146620d..0dd9bb873130 100644 --- a/drivers/iio/industrialio-trigger.c +++ b/drivers/iio/industrialio-trigger.c @@ -127,12 +127,17 @@ static struct iio_trigger *iio_trigger_find_by_name(const char *name, void iio_trigger_poll(struct iio_trigger *trig, s64 time) { int i; - if (!trig->use_count) - for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) - if (trig->subirqs[i].enabled) { - trig->use_count++; + + if (!atomic_read(&trig->use_count)) { + atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER); + + for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) { + if (trig->subirqs[i].enabled) generic_handle_irq(trig->subirq_base + i); - } + else + iio_trigger_notify_done(trig); + } + } } EXPORT_SYMBOL(iio_trigger_poll); @@ -146,19 +151,24 @@ EXPORT_SYMBOL(iio_trigger_generic_data_rdy_poll); void iio_trigger_poll_chained(struct iio_trigger *trig, s64 time) { int i; - if (!trig->use_count) - for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) - if (trig->subirqs[i].enabled) { - trig->use_count++; + + if (!atomic_read(&trig->use_count)) { + atomic_set(&trig->use_count, CONFIG_IIO_CONSUMERS_PER_TRIGGER); + + for (i = 0; i < CONFIG_IIO_CONSUMERS_PER_TRIGGER; i++) { + if (trig->subirqs[i].enabled) handle_nested_irq(trig->subirq_base + i); - } + else + iio_trigger_notify_done(trig); + } + } } EXPORT_SYMBOL(iio_trigger_poll_chained); void iio_trigger_notify_done(struct iio_trigger *trig) { - trig->use_count--; - if (trig->use_count == 0 && trig->ops && trig->ops->try_reenable) + if (atomic_dec_and_test(&trig->use_count) && trig->ops && + trig->ops->try_reenable) if (trig->ops->try_reenable(trig)) /* Missed an interrupt so launch new poll now */ iio_trigger_poll(trig, 0); diff --git a/include/linux/iio/trigger.h b/include/linux/iio/trigger.h index 3869c525b052..369cf2cd5144 100644 --- a/include/linux/iio/trigger.h +++ b/include/linux/iio/trigger.h @@ -8,6 +8,7 @@ */ #include #include +#include #ifndef _IIO_TRIGGER_H_ #define _IIO_TRIGGER_H_ @@ -61,7 +62,7 @@ struct iio_trigger { struct list_head list; struct list_head alloc_list; - int use_count; + atomic_t use_count; struct irq_chip subirq_chip; int subirq_base; From b1451e546899bc8f450773b2af02e0cd000cf1fa Mon Sep 17 00:00:00 2001 From: "Patil, Rachna" Date: Sat, 20 Jul 2013 17:27:00 +0100 Subject: [PATCH 2/3] iio: ti_am335x_adc: Fix wrong samples received on 1st read Previously we tried to read data form ADC even before ADC sequencer finished sampling. This led to wrong samples. We now wait on ADC status register idle bit to be set. Signed-off-by: Patil, Rachna Signed-off-by: Zubair Lutfullah Signed-off-by: Jonathan Cameron --- drivers/iio/adc/ti_am335x_adc.c | 30 ++++++++++++++++++++-------- include/linux/mfd/ti_am335x_tscadc.h | 16 +++++++++++++++ 2 files changed, 38 insertions(+), 8 deletions(-) diff --git a/drivers/iio/adc/ti_am335x_adc.c b/drivers/iio/adc/ti_am335x_adc.c index 0ad208a69c29..3ceac3e91dde 100644 --- a/drivers/iio/adc/ti_am335x_adc.c +++ b/drivers/iio/adc/ti_am335x_adc.c @@ -60,7 +60,6 @@ static void tiadc_step_config(struct tiadc_device *adc_dev) { unsigned int stepconfig; int i, steps; - u32 step_en; /* * There are 16 configurable steps and 8 analog input @@ -86,8 +85,7 @@ static void tiadc_step_config(struct tiadc_device *adc_dev) adc_dev->channel_step[i] = steps; steps++; } - step_en = get_adc_step_mask(adc_dev); - am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en); + } static const char * const chan_name_ain[] = { @@ -142,10 +140,22 @@ static int tiadc_read_raw(struct iio_dev *indio_dev, int *val, int *val2, long mask) { struct tiadc_device *adc_dev = iio_priv(indio_dev); - int i; - unsigned int fifo1count, read; + int i, map_val; + unsigned int fifo1count, read, stepid; u32 step = UINT_MAX; bool found = false; + u32 step_en; + unsigned long timeout = jiffies + usecs_to_jiffies + (IDLE_TIMEOUT * adc_dev->channels); + step_en = get_adc_step_mask(adc_dev); + am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en); + + /* Wait for ADC sequencer to complete sampling */ + while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) { + if (time_after(jiffies, timeout)) + return -EAGAIN; + } + map_val = chan->channel + TOTAL_CHANNELS; /* * When the sub-system is first enabled, @@ -170,12 +180,16 @@ static int tiadc_read_raw(struct iio_dev *indio_dev, fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); for (i = 0; i < fifo1count; i++) { read = tiadc_readl(adc_dev, REG_FIFO1); - if (read >> 16 == step) { - *val = read & 0xfff; + stepid = read & FIFOREAD_CHNLID_MASK; + stepid = stepid >> 0x10; + + if (stepid == map_val) { + read = read & FIFOREAD_DATA_MASK; found = true; + *val = read; } } - am335x_tsc_se_update(adc_dev->mfd_tscadc); + if (found == false) return -EBUSY; return IIO_VAL_INT; diff --git a/include/linux/mfd/ti_am335x_tscadc.h b/include/linux/mfd/ti_am335x_tscadc.h index 8d73fe29796a..db1791bb997a 100644 --- a/include/linux/mfd/ti_am335x_tscadc.h +++ b/include/linux/mfd/ti_am335x_tscadc.h @@ -113,11 +113,27 @@ #define CNTRLREG_8WIRE CNTRLREG_AFE_CTRL(3) #define CNTRLREG_TSCENB BIT(7) +/* FIFO READ Register */ +#define FIFOREAD_DATA_MASK (0xfff << 0) +#define FIFOREAD_CHNLID_MASK (0xf << 16) + +/* Sequencer Status */ +#define SEQ_STATUS BIT(5) + #define ADC_CLK 3000000 #define MAX_CLK_DIV 7 #define TOTAL_STEPS 16 #define TOTAL_CHANNELS 8 +/* +* ADC runs at 3MHz, and it takes +* 15 cycles to latch one data output. +* Hence the idle time for ADC to +* process one sample data would be +* around 5 micro seconds. +*/ +#define IDLE_TIMEOUT 5 /* microsec */ + #define TSCADC_CELLS 2 struct ti_tscadc_dev { From 02073798a6b081bf74e6c10d6f7e7a693c067ecd Mon Sep 17 00:00:00 2001 From: Piotr Sarna Date: Mon, 29 Jul 2013 12:25:20 +0200 Subject: [PATCH 3/3] staging: zcache: fix "zcache=" kernel parameter Commit 835f2f5 ("staging: zcache: enable zcache to be built/loaded as a module") introduced an incorrect handling of "zcache=" parameter. Inside zcache_comp_init() function, zcache_comp_name variable is checked for being empty. If not empty, the above variable is tested for being compatible with Crypto API. Unfortunately, after that function ends unconditionally (by the "goto out" directive) and returns: - non-zero value if verification succeeded, wrongly indicating an error - zero value if verification failed, falsely informing that function zcache_comp_init() ended properly. A solution to this problem is as following: 1. Move the "goto out" directive inside the "if (!ret)" statement 2. In case that crypto_has_comp() returned 0, change the value of ret to non-zero before "goto out" to indicate an error. This patch replaces an earlier one from Michal Hocko (based on report from Cristian Rodriguez): http://permalink.gmane.org/gmane.linux.kernel.mm/102484 It also addressed the same issue but didn't fix the zcache_comp_init() for case when the compressor data passed to "zcache=" option was invalid or unsupported. Signed-off-by: Piotr Sarna [bzolnier: updated patch description] Acked-by: Bartlomiej Zolnierkiewicz Signed-off-by: Kyungmin Park Acked-by: Konrad Rzeszutek Wilk Acked-by: Michal Hocko Cc: stable # 3.10 Cc: Cristian Rodriguez Cc: Bob Liu Signed-off-by: Greg Kroah-Hartman --- drivers/staging/zcache/zcache-main.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/drivers/staging/zcache/zcache-main.c b/drivers/staging/zcache/zcache-main.c index dcceed29d31a..81972fa47beb 100644 --- a/drivers/staging/zcache/zcache-main.c +++ b/drivers/staging/zcache/zcache-main.c @@ -1811,10 +1811,12 @@ static int zcache_comp_init(void) #else if (*zcache_comp_name != '\0') { ret = crypto_has_comp(zcache_comp_name, 0, 0); - if (!ret) + if (!ret) { pr_info("zcache: %s not supported\n", zcache_comp_name); - goto out; + ret = 1; + goto out; + } } if (!ret) strcpy(zcache_comp_name, "lzo");