From 48c302dc8f3acc1b0ef56a28569bc6a35b9b0e60 Mon Sep 17 00:00:00 2001 From: Logan Gunthorpe Date: Thu, 3 Aug 2017 12:19:43 -0600 Subject: [PATCH] NTB: switchtec: Add link event notifier callback 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 Reviewed-by: Stephen Bates Reviewed-by: Kurt Schwemmer Acked-by: Bjorn Helgaas Signed-off-by: Jon Mason --- 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 39c9218d733f..807569e62bee 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -978,6 +978,49 @@ 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); @@ -1030,6 +1073,7 @@ 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); @@ -1073,6 +1117,9 @@ 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); @@ -1092,6 +1139,7 @@ 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 { @@ -1116,6 +1164,8 @@ 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); @@ -1242,6 +1292,7 @@ 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 9c2be7631257..d8159944f013 100644 --- a/include/linux/switchtec.h +++ b/include/linux/switchtec.h @@ -353,6 +353,10 @@ 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) -- 2.30.2