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authorMika Westerberg <mika.westerberg@linux.intel.com>2017-10-02 13:38:35 +0300
committerDavid S. Miller <davem@davemloft.net>2017-10-02 11:24:41 -0700
commit8c6bba10fb9262d7b3a11e86a40621d5b37810a6 (patch)
treedd1ea0a7e55932118808c6721a6da67adf044aa3
parentd1ff70241a275133e1a0258b7c23588b122276c8 (diff)
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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: Michael Jamet <michael.jamet@intel.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com> Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Signed-off-by: David S. Miller <davem@davemloft.net>
-rw-r--r--drivers/thunderbolt/nhi.c23
-rw-r--r--drivers/thunderbolt/nhi_regs.h2
2 files changed, 22 insertions, 3 deletions
diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
index 05af126a2435..8a7a3d0133f9 100644
--- a/drivers/thunderbolt/nhi.c
+++ b/drivers/thunderbolt/nhi.c
@@ -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);
diff --git a/drivers/thunderbolt/nhi_regs.h b/drivers/thunderbolt/nhi_regs.h
index 09ed574e92ff..46eff69b19ad 100644
--- a/drivers/thunderbolt/nhi_regs.h
+++ b/drivers/thunderbolt/nhi_regs.h
@@ -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