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Groups > linux.kernel > #1677351

[PATCH 04/16] switchtec: add link event notifier callback

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In order for the switchtec NTB code to handle link change events we
create a notifier callback in the switchtec code which gets called
whenever an appropriate event interrupt occurs.

In order to preserve userspace's ability to follow these events,
we compare the event count with a stored copy from last time we
checked.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Stephen Bates <sbates@raithlin.com>
Reviewed-by: Kurt Schwemmer <kurt.schwemmer@microsemi.com>
---
 drivers/pci/switch/switchtec.c | 51 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/switchtec.h      |  4 ++++
 2 files changed, 55 insertions(+)

diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
index fc139ee3fa73..8fb01d7a793c 100644
--- a/drivers/pci/switch/switchtec.c
+++ b/drivers/pci/switch/switchtec.c
@@ -969,6 +969,49 @@ static const struct file_operations switchtec_fops = {
 	.compat_ioctl = switchtec_dev_ioctl,
 };
 
+static void link_event_work(struct work_struct *work)
+{
+	struct switchtec_dev *stdev;
+
+	stdev = container_of(work, struct switchtec_dev, link_event_work);
+
+	if (stdev->link_notifier)
+		stdev->link_notifier(stdev);
+}
+
+static void check_link_state_events(struct switchtec_dev *stdev)
+{
+	int idx;
+	u32 reg;
+	int count;
+	int occurred = 0;
+
+	for (idx = 0; idx < stdev->pff_csr_count; idx++) {
+		reg = ioread32(&stdev->mmio_pff_csr[idx].link_state_hdr);
+		dev_dbg(&stdev->dev, "link_state: %d->%08x\n", idx, reg);
+		count = (reg >> 5) & 0xFF;
+
+		if (count != stdev->link_event_count[idx]) {
+			occurred = 1;
+			stdev->link_event_count[idx] = count;
+		}
+	}
+
+	if (occurred)
+		schedule_work(&stdev->link_event_work);
+}
+
+static void enable_link_state_events(struct switchtec_dev *stdev)
+{
+	int idx;
+
+	for (idx = 0; idx < stdev->pff_csr_count; idx++) {
+		iowrite32(SWITCHTEC_EVENT_CLEAR |
+			  SWITCHTEC_EVENT_EN_IRQ,
+			  &stdev->mmio_pff_csr[idx].link_state_hdr);
+	}
+}
+
 static void stdev_release(struct device *dev)
 {
 	struct switchtec_dev *stdev = to_stdev(dev);
@@ -1021,6 +1064,7 @@ static struct switchtec_dev *stdev_create(struct pci_dev *pdev)
 	stdev->mrpc_busy = 0;
 	INIT_WORK(&stdev->mrpc_work, mrpc_event_work);
 	INIT_DELAYED_WORK(&stdev->mrpc_timeout, mrpc_timeout_work);
+	INIT_WORK(&stdev->link_event_work, link_event_work);
 	init_waitqueue_head(&stdev->event_wq);
 	atomic_set(&stdev->event_cnt, 0);
 
@@ -1064,6 +1108,9 @@ static int mask_event(struct switchtec_dev *stdev, int eid, int idx)
 	if (!(hdr & SWITCHTEC_EVENT_OCCURRED && hdr & SWITCHTEC_EVENT_EN_IRQ))
 		return 0;
 
+	if (eid == SWITCHTEC_IOCTL_EVENT_LINK_STATE)
+		return 0;
+
 	dev_dbg(&stdev->dev, "%s: %d %d %x\n", __func__, eid, idx, hdr);
 	hdr &= ~(SWITCHTEC_EVENT_EN_IRQ | SWITCHTEC_EVENT_OCCURRED);
 	iowrite32(hdr, hdr_reg);
@@ -1083,6 +1130,7 @@ static int mask_all_events(struct switchtec_dev *stdev, int eid)
 		for (idx = 0; idx < stdev->pff_csr_count; idx++) {
 			if (!stdev->pff_local[idx])
 				continue;
+
 			count += mask_event(stdev, eid, idx);
 		}
 	} else {
@@ -1107,6 +1155,8 @@ static irqreturn_t switchtec_event_isr(int irq, void *dev)
 		iowrite32(reg, &stdev->mmio_part_cfg->mrpc_comp_hdr);
 	}
 
+	check_link_state_events(stdev);
+
 	for (eid = 0; eid < SWITCHTEC_IOCTL_MAX_EVENTS; eid++)
 		event_count += mask_all_events(stdev, eid);
 
@@ -1233,6 +1283,7 @@ static int switchtec_pci_probe(struct pci_dev *pdev,
 	iowrite32(SWITCHTEC_EVENT_CLEAR |
 		  SWITCHTEC_EVENT_EN_IRQ,
 		  &stdev->mmio_part_cfg->mrpc_comp_hdr);
+	enable_link_state_events(stdev);
 
 	rc = cdev_device_add(&stdev->cdev, &stdev->dev);
 	if (rc)
diff --git a/include/linux/switchtec.h b/include/linux/switchtec.h
index a75f3d7e6876..6a056ffbc439 100644
--- a/include/linux/switchtec.h
+++ b/include/linux/switchtec.h
@@ -344,6 +344,10 @@ struct switchtec_dev {
 
 	wait_queue_head_t event_wq;
 	atomic_t event_cnt;
+
+	struct work_struct link_event_work;
+	void (*link_notifier)(struct switchtec_dev *stdev);
+	u8 link_event_count[SWITCHTEC_MAX_PFF_CSR];
 };
 
 static inline struct switchtec_dev *to_stdev(struct device *dev)
-- 
2.11.0

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Thread

[PATCH 00/16] Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 05:30 +0200
  [PATCH 14/16] switchtec_ntb: implement scratchpad registers Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 05:30 +0200
    RE: [PATCH 14/16] switchtec_ntb: implement scratchpad registers "Allen Hubbe" <Allen.Hubbe@dell.com> - 2017-06-29 20:20 +0200
      Re: [PATCH 14/16] switchtec_ntb: implement scratchpad registers Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 20:40 +0200
  [PATCH 09/16] switchtec_ntb: initialize hardware for memory windows Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 05:30 +0200
  [PATCH 01/16] switchtec: move structure definitions into a common header Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 05:30 +0200
  [PATCH 04/16] switchtec: add link event notifier callback Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 05:40 +0200
  [PATCH 05/16] ntb: ensure ntb_mw_get_align is only called when the link is up Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 05:40 +0200
    RE: [PATCH 05/16] ntb: ensure ntb_mw_get_align is only called when the link is up "Allen Hubbe" <Allen.Hubbe@dell.com> - 2017-06-29 20:20 +0200
  [PATCH 12/16] switchtec_ntb: add link management Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 05:40 +0200
    RE: [PATCH 12/16] switchtec_ntb: add link management "Allen Hubbe" <Allen.Hubbe@dell.com> - 2017-06-29 20:20 +0200
      Re: [PATCH 12/16] switchtec_ntb: add link management Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 20:40 +0200
  [PATCH 11/16] switchtec_ntb: add skeleton ntb driver Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 05:40 +0200
  [PATCH 10/16] switchtec_ntb: initialize hardware for doorbells and messages Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 05:40 +0200
  Re: [PATCH 00/16] Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2017-06-29 17:20 +0200
    Re: [PATCH 00/16] Logan Gunthorpe <logang@deltatee.com> - 2017-06-29 17:40 +0200

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