[PATCH v5 03/15] thunderbolt: Setup control channel

Andreas Noever
2014-06-03T20:09:55Z

Add struct tb which will contain our view of the thunderbolt bus. For
now it just contains a pointer to the control channel and a workqueue
for hotplug events.

Add thunderbolt_alloc_and_start() and thunderbolt_shutdown_and_free()
which are responsible for setup and teardown of struct tb.

Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
---
drivers/thunderbolt/Makefile | 2 +-
drivers/thunderbolt/nhi.c | 18 +++++-
drivers/thunderbolt/tb.c | 134 +++++++++++++++++++++++++++++++++++++++++++
drivers/thunderbolt/tb.h | 35 +++++++++++
4 files changed, 186 insertions(+), 3 deletions(-)
create mode 100644 drivers/thunderbolt/tb.c
create mode 100644 drivers/thunderbolt/tb.h

diff --git a/drivers/thunderbolt/Makefile b/drivers/thunderbolt/Makefile
index 4b21c99..1f996bb 100644
--- a/drivers/thunderbolt/Makefile
+++ b/drivers/thunderbolt/Makefile
@@ -1,3 +1,3 @@
obj-${CONFIG_THUNDERBOLT} := thunderbolt.o
-thunderbolt-objs := nhi.o ctl.o
+thunderbolt-objs := nhi.o ctl.o tb.o

diff --git a/drivers/thunderbolt/nhi.c b/drivers/thunderbolt/nhi.c
index 11070ff..d2b9ce8 100644
--- a/drivers/thunderbolt/nhi.c
+++ b/drivers/thunderbolt/nhi.c
@@ -16,6 +16,7 @@

#include "nhi.h"
#include "nhi_regs.h"
+#include "tb.h"

#define RING_TYPE(ring) ((ring)->is_tx ? "TX ring" : "RX ring")

@@ -517,6 +518,7 @@ static void nhi_shutdown(struct tb_nhi *nhi)
static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
{
struct tb_nhi *nhi;
+ struct tb *tb;
int res;

res = pcim_enable_device(pdev);
@@ -575,14 +577,26 @@ static int nhi_probe(struct pci_dev *pdev, const struct pci_device_id *id)
/* magic value - clock related? */
iowrite32(3906250 / 10000, nhi->iobase + 0x38c00);

- pci_set_drvdata(pdev, nhi);
+ dev_info(&nhi->pdev->dev, "NHI initialized, starting thunderbolt\n");
+ tb = thunderbolt_alloc_and_start(nhi);
+ if (!tb) {
+ /*
+ * At this point the RX/TX rings might already have been
+ * activated. Do a proper shutdown.
+ */
+ nhi_shutdown(nhi);
+ return -EIO;
+ }
+ pci_set_drvdata(pdev, tb);

return 0;
}

static void nhi_remove(struct pci_dev *pdev)
{
- struct tb_nhi *nhi = pci_get_drvdata(pdev);
+ struct tb *tb = pci_get_drvdata(pdev);
+ struct tb_nhi *nhi = tb->nhi;
+ thunderbolt_shutdown_and_free(tb);
nhi_shutdown(nhi);
}

diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
new file mode 100644
index 0000000..6920979
--- /dev/null
+++ b/drivers/thunderbolt/tb.c
@@ -0,0 +1,134 @@
+/*
+ * Thunderbolt Cactus Ridge driver - bus logic (NHI independent)
+ *
+ * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
+ */
+
+#include <linux/slab.h>
+#include <linux/errno.h>
+#include <linux/delay.h>
+
+#include "tb.h"
+
+/* hotplug handling */
+
+struct tb_hotplug_event {
+ struct work_struct work;
+ struct tb *tb;
+ u64 route;
+ u8 port;
+ bool unplug;
+};
+
+/**
+ * tb_handle_hotplug() - handle hotplug event
+ *
+ * Executes on tb->wq.
+ */
+static void tb_handle_hotplug(struct work_struct *work)
+{
+ struct tb_hotplug_event *ev = container_of(work, typeof(*ev), work);
+ struct tb *tb = ev->tb;
+ mutex_lock(&tb->lock);
+ if (!tb->hotplug_active)
+ goto out; /* during init, suspend or shutdown */
+
+ /* do nothing for now */
+out:
+ mutex_unlock(&tb->lock);
+ kfree(ev);
+}
+
+/**
+ * tb_schedule_hotplug_handler() - callback function for the control channel
+ *
+ * Delegates to tb_handle_hotplug.
+ */
+static void tb_schedule_hotplug_handler(void *data, u64 route, u8 port,
+ bool unplug)
+{
+ struct tb *tb = data;
+ struct tb_hotplug_event *ev = kmalloc(sizeof(*ev), GFP_KERNEL);
+ if (!ev)
+ return;
+ INIT_WORK(&ev->work, tb_handle_hotplug);
+ ev->tb = tb;
+ ev->route = route;
+ ev->port = port;
+ ev->unplug = unplug;
+ queue_work(tb->wq, &ev->work);
+}
+
+/**
+ * thunderbolt_shutdown_and_free() - shutdown everything
+ *
+ * Free all switches and the config channel.
+ *
+ * Used in the error path of thunderbolt_alloc_and_start.
+ */
+void thunderbolt_shutdown_and_free(struct tb *tb)
+{
+ mutex_lock(&tb->lock);
+
+ if (tb->ctl) {
+ tb_ctl_stop(tb->ctl);
+ tb_ctl_free(tb->ctl);
+ }
+ tb->ctl = NULL;
+ tb->hotplug_active = false; /* signal tb_handle_hotplug to quit */
+
+ /* allow tb_handle_hotplug to acquire the lock */
+ mutex_unlock(&tb->lock);
+ if (tb->wq) {
+ flush_workqueue(tb->wq);
+ destroy_workqueue(tb->wq);
+ tb->wq = NULL;
+ }
+ mutex_destroy(&tb->lock);
+ kfree(tb);
+}
+
+/**
+ * thunderbolt_alloc_and_start() - setup the thunderbolt bus
+ *
+ * Allocates a tb_cfg control channel, initializes the root switch, enables
+ * plug events and activates pci devices.
+ *
+ * Return: Returns NULL on error.
+ */
+struct tb *thunderbolt_alloc_and_start(struct tb_nhi *nhi)
+{
+ struct tb *tb;
+
+ tb = kzalloc(sizeof(*tb), GFP_KERNEL);
+ if (!tb)
+ return NULL;
+
+ tb->nhi = nhi;
+ mutex_init(&tb->lock);
+ mutex_lock(&tb->lock);
+
+ tb->wq = alloc_ordered_workqueue("thunderbolt", 0);
+ if (!tb->wq)
+ goto err_locked;
+
+ tb->ctl = tb_ctl_alloc(tb->nhi, tb_schedule_hotplug_handler, tb);
+ if (!tb->ctl)
+ goto err_locked;
+ /*
+ * tb_schedule_hotplug_handler may be called as soon as the config
+ * channel is started. Thats why we have to hold the lock here.
+ */
+ tb_ctl_start(tb->ctl);
+
+ /* Allow tb_handle_hotplug to progress events */
+ tb->hotplug_active = true;
+ mutex_unlock(&tb->lock);
+ return tb;
+
+err_locked:
+ mutex_unlock(&tb->lock);
+ thunderbolt_shutdown_and_free(tb);
+ return NULL;
+}
+
diff --git a/drivers/thunderbolt/tb.h b/drivers/thunderbolt/tb.h
new file mode 100644
index 0000000..6055dfd
--- /dev/null
+++ b/drivers/thunderbolt/tb.h
@@ -0,0 +1,35 @@
+/*
+ * Thunderbolt Cactus Ridge driver - bus logic (NHI independent)
+ *
+ * Copyright (c) 2014 Andreas Noever <andreas.noever@gmail.com>
+ */
+
+#ifndef TB_H_
+#define TB_H_
+
+#include "ctl.h"
+
+/**
+ * struct tb - main thunderbolt bus structure
+ */
+struct tb {
+ struct mutex lock; /*
+ * Big lock. Must be held when accessing cfg or
+ * any struct tb_switch / struct tb_port.
+ */
+ struct tb_nhi *nhi;
+ struct tb_ctl *ctl;
+ struct workqueue_struct *wq; /* ordered workqueue for plug events */
+ bool hotplug_active; /*
+ * tb_handle_hotplug will stop progressing plug
+ * events and exit if this is not set (it needs to
+ * acquire the lock one more time). Used to drain
+ * wq after cfg has been paused.
+ */
+
+};
+
+struct tb *thunderbolt_alloc_and_start(struct tb_nhi *nhi);
+void thunderbolt_shutdown_and_free(struct tb *tb);
+
+#endif
--
2.0.0