Commit 8c6bba10 authored by Mika Westerberg's avatar Mika Westerberg Committed by David S. Miller
Browse files

thunderbolt: Configure interrupt throttling for all interrupts 



This will keep the interrupt delivery rate reasonable. The value used
here (128 us) is a recommendation from the hardware people.

This code is based on the work done by Amir Levy and Michael Jamet.

Signed-off-by: default avatarMichael Jamet <michael.jamet@intel.com>
Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: default avatarYehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent d1ff7024

drivers/thunderbolt/nhi.c

+20 −3
Original line number Diff line number Diff line
@@ -651,6 +651,22 @@ static int nhi_suspend_noirq(struct device *dev) 
	return tb_domain_suspend_noirq(tb);

}



static void nhi_enable_int_throttling(struct tb_nhi *nhi)

{

	/* Throttling is specified in 256ns increments */

	u32 throttle = DIV_ROUND_UP(128 * NSEC_PER_USEC, 256);

	unsigned int i;



	/*

	 * Configure interrupt throttling for all vectors even if we

	 * only use few.

	 */

	for (i = 0; i < MSIX_MAX_VECS; i++) {

		u32 reg = REG_INT_THROTTLING_RATE + i * 4;

		iowrite32(throttle, nhi->iobase + reg);

	}

}



static int nhi_resume_noirq(struct device *dev)

{

	struct pci_dev *pdev = to_pci_dev(dev);
@@ -663,6 +679,8 @@ static int nhi_resume_noirq(struct device *dev) 
	 */

	if (!pci_device_is_present(pdev))

		tb->nhi->going_away = true;

	else

		nhi_enable_int_throttling(tb->nhi);



	return tb_domain_resume_noirq(tb);

}
@@ -717,6 +735,8 @@ static int nhi_init_msi(struct tb_nhi *nhi) 
	/* In case someone left them on. */

	nhi_disable_interrupts(nhi);



	nhi_enable_int_throttling(nhi);



	ida_init(&nhi->msix_ida);



	/*
@@ -796,9 +816,6 @@ static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id) 


	pci_set_master(pdev);



	/* magic value - clock related? */

	iowrite32(3906250 / 10000, nhi->iobase + 0x38c00);



	tb = icm_probe(nhi);

	if (!tb)

		tb = tb_probe(nhi);

drivers/thunderbolt/nhi_regs.h

+2 −0
Original line number Diff line number Diff line
@@ -95,6 +95,8 @@ struct ring_desc { 
#define REG_RING_INTERRUPT_BASE	0x38200

#define RING_INTERRUPT_REG_COUNT(nhi) ((31 + 2 * nhi->hop_count) / 32)



#define REG_INT_THROTTLING_RATE	0x38c00



/* Interrupt Vector Allocation */

#define REG_INT_VEC_ALLOC_BASE	0x38c40

#define REG_INT_VEC_ALLOC_BITS	4

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