[PARISC] Use work queue in LED/LCD driver instead of tasklet. (34994952) · Commits · 戴 / test

arch/parisc/kernel/time.c

+0 −8

Original line number	Diff line number	Diff line
		@@ -89,14 +89,6 @@ irqreturn_t timer_interrupt(int irq, void dev_id, struct pt_regs regs)
		}
		}

		#ifdef CONFIG_CHASSIS_LCD_LED
		/* Only schedule the led tasklet on cpu 0, and only if it
		* is enabled.
		*/
		if (cpu == 0 && !atomic_read(&led_tasklet.count))
		tasklet_schedule(&led_tasklet);
		#endif

		/* check soft power switch status */
		if (cpu == 0 && !atomic_read(&power_tasklet.count))
		tasklet_schedule(&power_tasklet);

drivers/parisc/led.c

+112 −113

Original line number	Diff line number	Diff line
		@@ -18,6 +18,9 @@
		* Changes:
		* - Audit copy_from_user in led_proc_write.
		* Daniele Bellucci <bellucda@tiscali.it>
		* - Switch from using a tasklet to a work queue, so the led_LCD_driver
		* can sleep.
		* David Pye <dmp@davidmpye.dyndns.org>
		*/

		#include <linux/config.h>
		@@ -37,6 +40,7 @@
		#include <linux/proc_fs.h>
		#include <linux/ctype.h>
		#include <linux/blkdev.h>
		#include <linux/workqueue.h>
		#include <linux/rcupdate.h>
		#include <asm/io.h>
		#include <asm/processor.h>
		@@ -47,25 +51,30 @@
		#include <asm/uaccess.h>

		/* The control of the LEDs and LCDs on PARISC-machines have to be done
		completely in software. The necessary calculations are done in a tasklet
		which is scheduled at every timer interrupt and since the calculations
		may consume relatively much CPU-time some of the calculations can be
		completely in software. The necessary calculations are done in a work queue
		task which is scheduled regularly, and since the calculations may consume a
		relatively large amount of CPU time, some of the calculations can be
		turned off with the following variables (controlled via procfs) */

		static int led_type = -1;
		static int led_heartbeat = 1;
		static int led_diskio = 1;
		static int led_lanrxtx = 1;
		static unsigned char lastleds; /* LED state from most recent update */
		static unsigned int led_heartbeat = 1;
		static unsigned int led_diskio = 1;
		static unsigned int led_lanrxtx = 1;
		static char lcd_text[32];
		static char lcd_text_default[32];


		static struct workqueue_struct *led_wq;
		static void led_work_func(void *);
		static DECLARE_WORK(led_task, led_work_func, NULL);

		#if 0
		#define DPRINTK(x) printk x
		#else
		#define DPRINTK(x)
		#endif


		struct lcd_block {
		unsigned char command; /* stores the command byte */
		unsigned char on; /* value for turning LED on */
		@@ -116,12 +125,27 @@ lcd_info __attribute__((aligned(8))) =
		#define LCD_DATA_REG lcd_info.lcd_data_reg_addr
		#define LED_DATA_REG lcd_info.lcd_cmd_reg_addr /* LASI & ASP only */

		#define LED_HASLCD 1
		#define LED_NOLCD 0

		/* The workqueue must be created at init-time */
		static int start_task(void)
		{
		/* Display the default text now */
		if (led_type == LED_HASLCD) lcd_print( lcd_text_default );

		/* Create the work queue and queue the LED task */
		led_wq = create_singlethread_workqueue("led_wq");
		queue_work(led_wq, &led_task);

		return 0;
		}

		device_initcall(start_task);

		/* ptr to LCD/LED-specific function */
		static void (*led_func_ptr) (unsigned char);

		#define LED_HASLCD 1
		#define LED_NOLCD 0
		#ifdef CONFIG_PROC_FS
		static int led_proc_read(char page, char *start, off_t off, int count,
		int eof, void data)
		@@ -287,51 +311,34 @@ static void led_LASI_driver(unsigned char leds)
		**
		** led_LCD_driver()
		**
		** The logic of the LCD driver is, that we write at every scheduled call
		** only to one of LCD_CMD_REG _or_ LCD_DATA_REG - registers.
		** That way we don't need to let this tasklet busywait for min_cmd_delay
		** milliseconds.
		**
		** TODO: check the value of "min_cmd_delay" against the value of HZ.
		**
		*/
		static void led_LCD_driver(unsigned char leds)
		{
		static int last_index; /* 0:heartbeat, 1:disk, 2:lan_in, 3:lan_out */
		static int last_was_cmd;/* 0: CMD was written last, 1: DATA was last */
		struct lcd_block *block_ptr;
		int value;

		switch (last_index) {
		case 0: block_ptr = &lcd_info.heartbeat;
		value = leds & LED_HEARTBEAT;
		break;
		case 1: block_ptr = &lcd_info.disk_io;
		value = leds & LED_DISK_IO;
		break;
		case 2: block_ptr = &lcd_info.lan_rcv;
		value = leds & LED_LAN_RCV;
		break;
		case 3: block_ptr = &lcd_info.lan_tx;
		value = leds & LED_LAN_TX;
		break;
		default: /* should never happen: */
		return;
		}
		static int i;
		static unsigned char mask[4] = { LED_HEARTBEAT, LED_DISK_IO,
		LED_LAN_RCV, LED_LAN_TX };

		static struct lcd_block * blockp[4] = {
		&lcd_info.heartbeat,
		&lcd_info.disk_io,
		&lcd_info.lan_rcv,
		&lcd_info.lan_tx
		};

		if (last_was_cmd) {
		/* write the value to the LCD data port */
		gsc_writeb( value ? block_ptr->on : block_ptr->off, LCD_DATA_REG );
		} else {
		/* write the command-byte to the LCD command register */
		gsc_writeb( block_ptr->command, LCD_CMD_REG );
		}
		/* Convert min_cmd_delay to milliseconds */
		unsigned int msec_cmd_delay = 1 + (lcd_info.min_cmd_delay / 1000);

		for (i=0; i<4; ++i)
		{
		if ((leds & mask[i]) != (lastleds & mask[i]))
		{
		gsc_writeb( blockp[i]->command, LCD_CMD_REG );
		msleep(msec_cmd_delay);

		/* now update the vars for the next interrupt iteration */
		if (++last_was_cmd == 2) { /* switch between cmd & data */
		last_was_cmd = 0;
		if (++last_index == 4)
		last_index = 0; /* switch back to heartbeat index */
		gsc_writeb( leds & mask[i] ? blockp[i]->on :
		blockp[i]->off, LCD_DATA_REG );
		msleep(msec_cmd_delay);
		}
		}
		}

		@@ -356,7 +363,7 @@ static __inline__ int led_get_net_activity(void)

		rx_total = tx_total = 0;

		/* we are running as tasklet, so locking dev_base
		/* we are running as a workqueue task, so locking dev_base
		* for reading should be OK */
		read_lock(&dev_base_lock);
		rcu_read_lock();
		@@ -420,79 +427,63 @@ static __inline__ int led_get_diskio_activity(void)


		/*
		** led_tasklet_func()
		** led_work_func()
		**
		** is scheduled at every timer interrupt from time.c and
		** updates the chassis LCD/LED
		** manages when and which chassis LCD/LED gets updated

		TODO:
		- display load average (older machines like 715/64 have 4 "free" LED's for that)
		- optimizations
		*/

		#define HEARTBEAT_LEN (HZ*6/100)
		#define HEARTBEAT_2ND_RANGE_START (HZ*22/100)
		#define HEARTBEAT_LEN (HZ*10/100)
		#define HEARTBEAT_2ND_RANGE_START (HZ*28/100)
		#define HEARTBEAT_2ND_RANGE_END (HEARTBEAT_2ND_RANGE_START + HEARTBEAT_LEN)

		#define NORMALIZED_COUNT(count) (count/(HZ/100))
		#define LED_UPDATE_INTERVAL (1 + (HZ*19/1000))

		static void led_tasklet_func(unsigned long unused)
		static void led_work_func (void *unused)
		{
		static unsigned char lastleds;
		unsigned char currentleds; /* stores current value of the LEDs */
		static unsigned long count; /* static incremented value, not wrapped */
		static unsigned long last_jiffies;
		static unsigned long count_HZ; /* counter in range 0..HZ */
		unsigned char currentleds = 0; /* stores current value of the LEDs */

		/* exit if not initialized */
		if (!led_func_ptr)
		return;

		/* increment the local counters */
		++count;
		if (++count_HZ == HZ)
		/* increment the heartbeat timekeeper */
		count_HZ += jiffies - last_jiffies;
		last_jiffies = jiffies;
		if (count_HZ >= HZ)
		count_HZ = 0;

		currentleds = lastleds;

		if (led_heartbeat)
		if (likely(led_heartbeat))
		{
		/* flash heartbeat-LED like a real heart (2 x short then a long delay) */
		/* flash heartbeat-LED like a real heart
		* (2 x short then a long delay)
		*/
		if (count_HZ < HEARTBEAT_LEN \|\|
		(count_HZ>=HEARTBEAT_2ND_RANGE_START && count_HZ<HEARTBEAT_2ND_RANGE_END))
		(count_HZ >= HEARTBEAT_2ND_RANGE_START &&
		count_HZ < HEARTBEAT_2ND_RANGE_END))
		currentleds \|= LED_HEARTBEAT;
		else
		currentleds &= ~LED_HEARTBEAT;
		}

		/* look for network activity and flash LEDs respectively */
		if (led_lanrxtx && ((NORMALIZED_COUNT(count)+(8/2)) & 7) == 0)
		{
		currentleds &= ~(LED_LAN_RCV \| LED_LAN_TX);
		currentleds \|= led_get_net_activity();
		}

		/* avoid to calculate diskio-stats at same irq as netio-stats */
		if (led_diskio && (NORMALIZED_COUNT(count) & 7) == 0)
		{
		currentleds &= ~LED_DISK_IO;
		currentleds \|= led_get_diskio_activity();
		}
		if (likely(led_lanrxtx)) currentleds \|= led_get_net_activity();
		if (likely(led_diskio)) currentleds \|= led_get_diskio_activity();

		/* blink all LEDs twice a second if we got an Oops (HPMC) */
		if (oops_in_progress) {
		if (unlikely(oops_in_progress))
		currentleds = (count_HZ<=(HZ/2)) ? 0 : 0xff;
		}

		/* update the LCD/LEDs */
		if (currentleds != lastleds) {
		led_func_ptr(currentleds);
		if (currentleds != lastleds)
		{
		led_func_ptr(currentleds); /* Update the LCD/LEDs */
		lastleds = currentleds;
		}
		}

		/* main led tasklet struct (scheduled from time.c) */
		DECLARE_TASKLET_DISABLED(led_tasklet, led_tasklet_func, 0);

		queue_delayed_work(led_wq, &led_task, LED_UPDATE_INTERVAL);
		}

		/*
		** led_halt()
		@@ -522,8 +513,12 @@ static int led_halt(struct notifier_block nb, unsigned long event, void buf)
		default: return NOTIFY_DONE;
		}

		/* completely stop the LED/LCD tasklet */
		tasklet_disable(&led_tasklet);
		/* Cancel the work item and delete the queue */
		if (led_wq) {
		cancel_rearming_delayed_workqueue(led_wq, &led_task);
		destroy_workqueue(led_wq);
		led_wq = NULL;
		}

		if (lcd_info.model == DISPLAY_MODEL_LCD)
		lcd_print(txt);
		@@ -559,7 +554,6 @@ int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long d
		printk(KERN_INFO "LCD display at %lx,%lx registered\n",
		LCD_CMD_REG , LCD_DATA_REG);
		led_func_ptr = led_LCD_driver;
		lcd_print( lcd_text_default );
		led_type = LED_HASLCD;
		break;

		@@ -589,8 +583,10 @@ int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long d
		initialized++;
		register_reboot_notifier(&led_notifier);

		/* start the led tasklet for the first time */
		tasklet_enable(&led_tasklet);
		/* Ensure the work is queued */
		if (led_wq) {
		queue_work(led_wq, &led_task);
		}

		return 0;
		}
		@@ -626,8 +622,8 @@ void __init register_led_regions(void)
		** lcd_print()
		**
		** Displays the given string on the LCD-Display of newer machines.
		** lcd_print() disables the timer-based led tasklet during its
		** execution and enables it afterwards again.
		** lcd_print() disables/enables the timer-based led work queue to
		** avoid a race condition while writing the CMD/DATA register pair.
		**
		*/
		int lcd_print( char *str )
		@@ -637,8 +633,9 @@ int lcd_print( char *str )
		if (!led_func_ptr \|\| lcd_info.model != DISPLAY_MODEL_LCD)
		return 0;

		/* temporarily disable the led tasklet */
		tasklet_disable(&led_tasklet);
		/* temporarily disable the led work task */
		if (led_wq)
		cancel_rearming_delayed_workqueue(led_wq, &led_task);

		/* copy display string to buffer for procfs */
		strlcpy(lcd_text, str, sizeof(lcd_text));
		@@ -656,8 +653,10 @@ int lcd_print( char *str )
		udelay(lcd_info.min_cmd_delay);
		}

		/* re-enable the led tasklet */
		tasklet_enable(&led_tasklet);
		/* re-queue the work */
		if (led_wq) {
		queue_work(led_wq, &led_task);
		}

		return lcd_info.lcd_width;
		}

include/asm-parisc/led.h

+0 −3

Original line number	Diff line number	Diff line
		@@ -23,9 +23,6 @@

		#define LED_CMD_REG_NONE 0 /* NULL == no addr for the cmd register */

		/* led tasklet struct */
		extern struct tasklet_struct led_tasklet;

		/* register_led_driver() */
		int __init register_led_driver(int model, unsigned long cmd_reg, unsigned long data_reg);

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