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linux-next/drivers/iio/adc/xilinx-xadc.h
Xander Huff 70581e0ef8 iio: adc: xilinx-xadc: Push interrupts into hardirq context
The driver currently registers a pair of irq handlers using
request_threaded_irq(), however the synchronization mechanism between the
hardirq and the threadedirq handler is a regular spinlock.

Unfortunately, this breaks PREEMPT_RT builds, where a spinlock can sleep,
and is thus not able to be acquired from a hardirq handler. This patch gets
rid of the threaded handler and pushes all interrupt handling into the
hardirq context, and uses request_irq().

To validate that this change has no impact on RT performance, here are
cyclictest values with no processes running:

$ sudo cyclictest -S -m -p 98
policy: fifo: loadavg: 0.00 0.01 0.05 1/174 2539
T: 0 ( 1405) P:98 I:1000 C:167010520 Min: 9 Act: 12 Avg: 12 Max: 75
T: 1 ( 1862) P:98 I:1500 C:111340339 Min: 9 Act: 12 Avg: 12 Max: 73

Then, all xadc raw handles were accessed in a continuous loop via
/sys/bus/iio/devices/iio:device0:

$ sudo cyclictest -S -m -p 98
policy: fifo: loadavg: 7.84 7.70 7.63 3/182 4260
T: 0 ( 2559) P:98 I:1000 C:241557018 Min: 11 Act: 18 Avg: 21 Max: 74
T: 1 ( 2560) P:98 I:1500 C:161038006 Min: 10 Act: 21 Avg: 20 Max: 73

Signed-off-by: Xander Huff <xander.huff@ni.com>
Acked-by: Lars-Peter Clausen <lars@metafoo.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2015-08-16 10:51:27 +01:00

208 lines
5.5 KiB
C

/*
* Xilinx XADC driver
*
* Copyright 2013 Analog Devices Inc.
* Author: Lars-Peter Clauen <lars@metafoo.de>
*
* Licensed under the GPL-2.
*/
#ifndef __IIO_XILINX_XADC__
#define __IIO_XILINX_XADC__
#include <linux/interrupt.h>
#include <linux/mutex.h>
#include <linux/spinlock.h>
struct iio_dev;
struct clk;
struct xadc_ops;
struct platform_device;
void xadc_handle_events(struct iio_dev *indio_dev, unsigned long events);
int xadc_read_event_config(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, enum iio_event_type type,
enum iio_event_direction dir);
int xadc_write_event_config(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, enum iio_event_type type,
enum iio_event_direction dir, int state);
int xadc_read_event_value(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, enum iio_event_type type,
enum iio_event_direction dir, enum iio_event_info info,
int *val, int *val2);
int xadc_write_event_value(struct iio_dev *indio_dev,
const struct iio_chan_spec *chan, enum iio_event_type type,
enum iio_event_direction dir, enum iio_event_info info,
int val, int val2);
enum xadc_external_mux_mode {
XADC_EXTERNAL_MUX_NONE,
XADC_EXTERNAL_MUX_SINGLE,
XADC_EXTERNAL_MUX_DUAL,
};
struct xadc {
void __iomem *base;
struct clk *clk;
const struct xadc_ops *ops;
uint16_t threshold[16];
uint16_t temp_hysteresis;
unsigned int alarm_mask;
uint16_t *data;
struct iio_trigger *trigger;
struct iio_trigger *convst_trigger;
struct iio_trigger *samplerate_trigger;
enum xadc_external_mux_mode external_mux_mode;
unsigned int zynq_masked_alarm;
unsigned int zynq_intmask;
struct delayed_work zynq_unmask_work;
struct mutex mutex;
spinlock_t lock;
struct completion completion;
};
struct xadc_ops {
int (*read)(struct xadc *, unsigned int, uint16_t *);
int (*write)(struct xadc *, unsigned int, uint16_t);
int (*setup)(struct platform_device *pdev, struct iio_dev *indio_dev,
int irq);
void (*update_alarm)(struct xadc *, unsigned int);
unsigned long (*get_dclk_rate)(struct xadc *);
irqreturn_t (*interrupt_handler)(int, void *);
unsigned int flags;
};
static inline int _xadc_read_adc_reg(struct xadc *xadc, unsigned int reg,
uint16_t *val)
{
lockdep_assert_held(&xadc->mutex);
return xadc->ops->read(xadc, reg, val);
}
static inline int _xadc_write_adc_reg(struct xadc *xadc, unsigned int reg,
uint16_t val)
{
lockdep_assert_held(&xadc->mutex);
return xadc->ops->write(xadc, reg, val);
}
static inline int xadc_read_adc_reg(struct xadc *xadc, unsigned int reg,
uint16_t *val)
{
int ret;
mutex_lock(&xadc->mutex);
ret = _xadc_read_adc_reg(xadc, reg, val);
mutex_unlock(&xadc->mutex);
return ret;
}
static inline int xadc_write_adc_reg(struct xadc *xadc, unsigned int reg,
uint16_t val)
{
int ret;
mutex_lock(&xadc->mutex);
ret = _xadc_write_adc_reg(xadc, reg, val);
mutex_unlock(&xadc->mutex);
return ret;
}
/* XADC hardmacro register definitions */
#define XADC_REG_TEMP 0x00
#define XADC_REG_VCCINT 0x01
#define XADC_REG_VCCAUX 0x02
#define XADC_REG_VPVN 0x03
#define XADC_REG_VREFP 0x04
#define XADC_REG_VREFN 0x05
#define XADC_REG_VCCBRAM 0x06
#define XADC_REG_VCCPINT 0x0d
#define XADC_REG_VCCPAUX 0x0e
#define XADC_REG_VCCO_DDR 0x0f
#define XADC_REG_VAUX(x) (0x10 + (x))
#define XADC_REG_MAX_TEMP 0x20
#define XADC_REG_MAX_VCCINT 0x21
#define XADC_REG_MAX_VCCAUX 0x22
#define XADC_REG_MAX_VCCBRAM 0x23
#define XADC_REG_MIN_TEMP 0x24
#define XADC_REG_MIN_VCCINT 0x25
#define XADC_REG_MIN_VCCAUX 0x26
#define XADC_REG_MIN_VCCBRAM 0x27
#define XADC_REG_MAX_VCCPINT 0x28
#define XADC_REG_MAX_VCCPAUX 0x29
#define XADC_REG_MAX_VCCO_DDR 0x2a
#define XADC_REG_MIN_VCCPINT 0x2c
#define XADC_REG_MIN_VCCPAUX 0x2d
#define XADC_REG_MIN_VCCO_DDR 0x2e
#define XADC_REG_CONF0 0x40
#define XADC_REG_CONF1 0x41
#define XADC_REG_CONF2 0x42
#define XADC_REG_SEQ(x) (0x48 + (x))
#define XADC_REG_INPUT_MODE(x) (0x4c + (x))
#define XADC_REG_THRESHOLD(x) (0x50 + (x))
#define XADC_REG_FLAG 0x3f
#define XADC_CONF0_EC BIT(9)
#define XADC_CONF0_ACQ BIT(8)
#define XADC_CONF0_MUX BIT(11)
#define XADC_CONF0_CHAN(x) (x)
#define XADC_CONF1_SEQ_MASK (0xf << 12)
#define XADC_CONF1_SEQ_DEFAULT (0 << 12)
#define XADC_CONF1_SEQ_SINGLE_PASS (1 << 12)
#define XADC_CONF1_SEQ_CONTINUOUS (2 << 12)
#define XADC_CONF1_SEQ_SINGLE_CHANNEL (3 << 12)
#define XADC_CONF1_SEQ_SIMULTANEOUS (4 << 12)
#define XADC_CONF1_SEQ_INDEPENDENT (8 << 12)
#define XADC_CONF1_ALARM_MASK 0x0f0f
#define XADC_CONF2_DIV_MASK 0xff00
#define XADC_CONF2_DIV_OFFSET 8
#define XADC_CONF2_PD_MASK (0x3 << 4)
#define XADC_CONF2_PD_NONE (0x0 << 4)
#define XADC_CONF2_PD_ADC_B (0x2 << 4)
#define XADC_CONF2_PD_BOTH (0x3 << 4)
#define XADC_ALARM_TEMP_MASK BIT(0)
#define XADC_ALARM_VCCINT_MASK BIT(1)
#define XADC_ALARM_VCCAUX_MASK BIT(2)
#define XADC_ALARM_OT_MASK BIT(3)
#define XADC_ALARM_VCCBRAM_MASK BIT(4)
#define XADC_ALARM_VCCPINT_MASK BIT(5)
#define XADC_ALARM_VCCPAUX_MASK BIT(6)
#define XADC_ALARM_VCCODDR_MASK BIT(7)
#define XADC_THRESHOLD_TEMP_MAX 0x0
#define XADC_THRESHOLD_VCCINT_MAX 0x1
#define XADC_THRESHOLD_VCCAUX_MAX 0x2
#define XADC_THRESHOLD_OT_MAX 0x3
#define XADC_THRESHOLD_TEMP_MIN 0x4
#define XADC_THRESHOLD_VCCINT_MIN 0x5
#define XADC_THRESHOLD_VCCAUX_MIN 0x6
#define XADC_THRESHOLD_OT_MIN 0x7
#define XADC_THRESHOLD_VCCBRAM_MAX 0x8
#define XADC_THRESHOLD_VCCPINT_MAX 0x9
#define XADC_THRESHOLD_VCCPAUX_MAX 0xa
#define XADC_THRESHOLD_VCCODDR_MAX 0xb
#define XADC_THRESHOLD_VCCBRAM_MIN 0xc
#define XADC_THRESHOLD_VCCPINT_MIN 0xd
#define XADC_THRESHOLD_VCCPAUX_MIN 0xe
#define XADC_THRESHOLD_VCCODDR_MIN 0xf
#endif