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Commit e8483b57 authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Thomas Gleixner
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MIPS/BUS/CDMM: Convert to hotplug state machine 



Install the callbacks via the state machine and let the core invoke
the callbacks on the already online CPUs.

Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160818125731.27256-14-bigeasy@linutronix.de


Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
parent dfc616d8

drivers/bus/mips_cdmm.c

+12 −58
Original line number Diff line number Diff line
@@ -596,19 +596,20 @@ BUILD_PERDEV_HELPER(cpu_down) /* int mips_cdmm_cpu_down_helper(...) */ 
BUILD_PERDEV_HELPER(cpu_up)         /* int mips_cdmm_cpu_up_helper(...) */



/**

 * mips_cdmm_bus_down() - Tear down the CDMM bus.

 * @data:	Pointer to unsigned int CPU number.

 * mips_cdmm_cpu_down_prep() - Callback for CPUHP DOWN_PREP:

 *			       Tear down the CDMM bus.

 * @cpu:	unsigned int CPU number.

 *

 * This function is executed on the hotplugged CPU and calls the CDMM

 * driver cpu_down callback for all devices on that CPU.

 */

static long mips_cdmm_bus_down(void *data)

static int mips_cdmm_cpu_down_prep(unsigned int cpu)

{

	struct mips_cdmm_bus *bus;

	long ret;



	/* Inform all the devices on the bus */

	ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, data,

	ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, &cpu,

			       mips_cdmm_cpu_down_helper);



	/*
@@ -623,8 +624,8 @@ static long mips_cdmm_bus_down(void *data) 
}



/**

 * mips_cdmm_bus_up() - Bring up the CDMM bus.

 * @data:	Pointer to unsigned int CPU number.

 * mips_cdmm_cpu_online() - Callback for CPUHP ONLINE: Bring up the CDMM bus.

 * @cpu:	unsigned int CPU number.

 *

 * This work_on_cpu callback function is executed on a given CPU to discover

 * CDMM devices on that CPU, or to call the CDMM driver cpu_up callback for all
@@ -634,7 +635,7 @@ static long mips_cdmm_bus_down(void *data) 
 * initialisation. When CPUs are brought online the function is

 * invoked directly on the hotplugged CPU.

 */

static long mips_cdmm_bus_up(void *data)

static int mips_cdmm_cpu_online(unsigned int cpu)

{

	struct mips_cdmm_bus *bus;

	long ret;
@@ -651,50 +652,12 @@ static long mips_cdmm_bus_up(void *data) 
		mips_cdmm_bus_discover(bus);

	else

		/* Inform all the devices on the bus */

		ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, data,

		ret = bus_for_each_dev(&mips_cdmm_bustype, NULL, &cpu,

				       mips_cdmm_cpu_up_helper);



	return ret;

}



/**

 * mips_cdmm_cpu_notify() - Take action when a CPU is going online or offline.

 * @nb:		CPU notifier block .

 * @action:	Event that has taken place (CPU_*).

 * @data:	CPU number.

 *

 * This notifier is used to keep the CDMM buses updated as CPUs are offlined and

 * onlined. When CPUs go offline or come back online, so does their CDMM bus, so

 * devices must be informed. Also when CPUs come online for the first time the

 * devices on the CDMM bus need discovering.

 *

 * Returns:	NOTIFY_OK if event was used.

 *		NOTIFY_DONE if we didn't care.

 */

static int mips_cdmm_cpu_notify(struct notifier_block *nb,

				unsigned long action, void *data)

{

	unsigned int cpu = (unsigned int)data;



	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_ONLINE:

	case CPU_DOWN_FAILED:

		mips_cdmm_bus_up(&cpu);

		break;

	case CPU_DOWN_PREPARE:

		mips_cdmm_bus_down(&cpu);

		break;

	default:

		return NOTIFY_DONE;

	}



	return NOTIFY_OK;

}



static struct notifier_block mips_cdmm_cpu_nb = {

	.notifier_call = mips_cdmm_cpu_notify,

};



/**

 * mips_cdmm_init() - Initialise CDMM bus.

 *
@@ -703,7 +666,6 @@ static struct notifier_block mips_cdmm_cpu_nb = { 
 */

static int __init mips_cdmm_init(void)

{

	unsigned int cpu;

	int ret;



	/* Register the bus */
@@ -712,19 +674,11 @@ static int __init mips_cdmm_init(void) 
		return ret;



	/* We want to be notified about new CPUs */

	ret = register_cpu_notifier(&mips_cdmm_cpu_nb);

	if (ret) {

	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "bus/cdmm:online",

				mips_cdmm_cpu_online, mips_cdmm_cpu_down_prep);

	if (ret < 0)

		pr_warn("cdmm: Failed to register CPU notifier\n");

		goto out;

	}



	/* Discover devices on CDMM of online CPUs */

	for_each_online_cpu(cpu)

		work_on_cpu(cpu, mips_cdmm_bus_up, &cpu);



	return 0;

out:

	bus_unregister(&mips_cdmm_bustype);

	return ret;

}

subsys_initcall(mips_cdmm_init);