Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit f2a4aa56 authored by Vineet Gupta's avatar Vineet Gupta
Browse files

ARC: [SMP] simplify IPI code 

* ipi_data is just a word, no need to keep it as struct

* find_next_bit() not needed to loop thru a 32bit word, ffs suffices
parent 53dc110c

arch/arc/kernel/smp.c

+28 −28
Original line number Diff line number Diff line
@@ -197,37 +197,31 @@ int __init setup_profiling_timer(unsigned int multiplier) 
/*              Inter Processor Interrupt Handling                           */

/*****************************************************************************/



/*

 * structures for inter-processor calls

 * A Collection of single bit ipi messages

 *

 */



/*

 * TODO_rajesh investigate tlb message types.

 * IPI Timer not needed because each ARC has an individual Interrupting Timer

 */

enum ipi_msg_type {

	IPI_NOP = 0,

	IPI_EMPTY = 0,

	IPI_RESCHEDULE = 1,

	IPI_CALL_FUNC,

	IPI_CPU_STOP

	IPI_CPU_STOP,

};



struct ipi_data {

	unsigned long bits;

};

/*

 * In arches with IRQ for each msg type (above), receiver can use IRQ-id  to

 * figure out what msg was sent. For those which don't (ARC has dedicated IPI

 * IRQ), the msg-type needs to be conveyed via per-cpu data

 */



static DEFINE_PER_CPU(struct ipi_data, ipi_data);

static DEFINE_PER_CPU(unsigned long, ipi_data);



static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg)

{

	struct ipi_data *ipi = &per_cpu(ipi_data, cpu);

	unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu);

	unsigned long flags;



	pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu);



	local_irq_save(flags);



	set_bit(msg, &ipi->bits);

	set_bit(msg, ipi_data_ptr);



	/* Call the platform specific cross-CPU call function  */

	if (plat_smp_ops.ipi_send)
@@ -275,12 +269,11 @@ static void ipi_cpu_stop(void) 
	machine_halt();

}



static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi)

static inline void __do_IPI(unsigned long pending)

{

	unsigned long msg = 0;

	while (pending) {



	do {

		msg = find_next_bit(ops, BITS_PER_LONG, msg+1);

		unsigned long msg = __ffs(pending);



		switch (msg) {

		case IPI_RESCHEDULE:
@@ -294,8 +287,14 @@ static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi) 
		case IPI_CPU_STOP:

			ipi_cpu_stop();

			break;



		default:

			pr_warn("IPI missing msg\n");



		}



		pending &= ~(1U << msg);

	}

	} while (msg < BITS_PER_LONG);

}



/*
@@ -304,9 +303,10 @@ static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi) 
 */

irqreturn_t do_IPI(int irq, void *dev_id)

{

	int cpu = smp_processor_id();

	struct ipi_data *ipi = &per_cpu(ipi_data, cpu);

	unsigned long ops;

	unsigned long pending;



	pr_debug("IPI [%ld] received on cpu %d\n",

		 *this_cpu_ptr(&ipi_data), smp_processor_id());



	if (plat_smp_ops.ipi_clear)

		plat_smp_ops.ipi_clear(irq);
@@ -315,8 +315,8 @@ irqreturn_t do_IPI(int irq, void *dev_id) 
	 * XXX: is this loop really needed

	 * And do we need to move ipi_clean inside

	 */

	while ((ops = xchg(&ipi->bits, 0)) != 0)

		__do_IPI(&ops, ipi);

	while ((pending = xchg(this_cpu_ptr(&ipi_data), 0)) != 0)

		__do_IPI(pending);



	return IRQ_HANDLED;

}