[PATCH v2 08/16] switchtec_ntb: introduce initial NTB driver

Logan Gunthorpe
2017-07-18T16:04:28Z

Seeing the Switchtec NTB hardware shares the same endpoint as the
management endpoint we utilize the class_interface API to register
an NTB driver for every Switchtec device in the system that has the
NTB class code.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Stephen Bates <sbates@raithlin.com>
Reviewed-by: Kurt Schwemmer <kurt.schwemmer@microsemi.com>
---
MAINTAINERS | 1 +
drivers/ntb/hw/Kconfig | 1 +
drivers/ntb/hw/Makefile | 1 +
drivers/ntb/hw/mscc/Kconfig | 9 +++++
drivers/ntb/hw/mscc/Makefile | 1 +
drivers/ntb/hw/mscc/switchtec_ntb.c | 81 +++++++++++++++++++++++++++++++++++++
drivers/pci/switch/switchtec.c | 3 ++
include/linux/switchtec.h | 4 ++
8 files changed, 101 insertions(+)
create mode 100644 drivers/ntb/hw/mscc/Kconfig
create mode 100644 drivers/ntb/hw/mscc/Makefile
create mode 100644 drivers/ntb/hw/mscc/switchtec_ntb.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 4ff2ad7c1c7b..6e491ce5e876 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -10147,6 +10147,7 @@ F: Documentation/ABI/testing/sysfs-class-switchtec
F: drivers/pci/switch/switchtec*
F: include/uapi/linux/switchtec_ioctl.h
F: include/linux/switchtec.h
+F: drivers/ntb/hw/mscc/

PCI DRIVER FOR NVIDIA TEGRA
M: Thierry Reding <thierry.reding@gmail.com>
diff --git a/drivers/ntb/hw/Kconfig b/drivers/ntb/hw/Kconfig
index a89243c9fdd3..e51b581fd102 100644
--- a/drivers/ntb/hw/Kconfig
+++ b/drivers/ntb/hw/Kconfig
@@ -1,3 +1,4 @@
source "drivers/ntb/hw/amd/Kconfig"
source "drivers/ntb/hw/idt/Kconfig"
source "drivers/ntb/hw/intel/Kconfig"
+source "drivers/ntb/hw/mscc/Kconfig"
diff --git a/drivers/ntb/hw/Makefile b/drivers/ntb/hw/Makefile
index 87332c3905f0..923c442db750 100644
--- a/drivers/ntb/hw/Makefile
+++ b/drivers/ntb/hw/Makefile
@@ -1,3 +1,4 @@
obj-$(CONFIG_NTB_AMD) += amd/
obj-$(CONFIG_NTB_IDT) += idt/
obj-$(CONFIG_NTB_INTEL) += intel/
+obj-$(CONFIG_NTB_SWITCHTEC) += mscc/
diff --git a/drivers/ntb/hw/mscc/Kconfig b/drivers/ntb/hw/mscc/Kconfig
new file mode 100644
index 000000000000..013ed6716438
--- /dev/null
+++ b/drivers/ntb/hw/mscc/Kconfig
@@ -0,0 +1,9 @@
+config NTB_SWITCHTEC
+ tristate "MicroSemi Switchtec Non-Transparent Bridge Support"
+ select PCI_SW_SWITCHTEC
+ help
+ Enables NTB support for Switchtec PCI switches. This also
+ selects the Switchtec management driver as they share the same
+ hardware interface.
+
+ If unsure, say N.
diff --git a/drivers/ntb/hw/mscc/Makefile b/drivers/ntb/hw/mscc/Makefile
new file mode 100644
index 000000000000..21907b364e19
--- /dev/null
+++ b/drivers/ntb/hw/mscc/Makefile
@@ -0,0 +1 @@
+obj-$(CONFIG_NTB_SWITCHTEC) += switchtec_ntb.o
diff --git a/drivers/ntb/hw/mscc/switchtec_ntb.c b/drivers/ntb/hw/mscc/switchtec_ntb.c
new file mode 100644
index 000000000000..253efba72275
--- /dev/null
+++ b/drivers/ntb/hw/mscc/switchtec_ntb.c
@@ -0,0 +1,81 @@
+/*
+ * Microsemi Switchtec(tm) PCIe Management Driver
+ * Copyright (c) 2017, Microsemi Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ */
+
+#include <linux/switchtec.h>
+#include <linux/module.h>
+
+MODULE_DESCRIPTION("Microsemi Switchtec(tm) NTB Driver");
+MODULE_VERSION("0.1");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Microsemi Corporation");
+
+struct switchtec_ntb {
+ struct switchtec_dev *stdev;
+};
+
+static int switchtec_ntb_add(struct device *dev,
+ struct class_interface *class_intf)
+{
+ struct switchtec_dev *stdev = to_stdev(dev);
+ struct switchtec_ntb *sndev;
+
+ stdev->sndev = NULL;
+
+ if (stdev->pdev->class != MICROSEMI_NTB_CLASSCODE)
+ return -ENODEV;
+
+ sndev = kzalloc_node(sizeof(*sndev), GFP_KERNEL, dev_to_node(dev));
+ if (!sndev)
+ return -ENOMEM;
+
+ sndev->stdev = stdev;
+
+ stdev->sndev = sndev;
+ dev_info(dev, "NTB device registered");
+
+ return 0;
+}
+
+void switchtec_ntb_remove(struct device *dev,
+ struct class_interface *class_intf)
+{
+ struct switchtec_dev *stdev = to_stdev(dev);
+ struct switchtec_ntb *sndev = stdev->sndev;
+
+ if (!sndev)
+ return;
+
+ stdev->sndev = NULL;
+ kfree(sndev);
+ dev_info(dev, "ntb device unregistered");
+}
+
+static struct class_interface switchtec_interface = {
+ .add_dev = switchtec_ntb_add,
+ .remove_dev = switchtec_ntb_remove,
+};
+
+static int __init switchtec_ntb_init(void)
+{
+ switchtec_interface.class = switchtec_class;
+ return class_interface_register(&switchtec_interface);
+}
+module_init(switchtec_ntb_init);
+
+static void __exit switchtec_ntb_exit(void)
+{
+ class_interface_unregister(&switchtec_interface);
+}
+module_exit(switchtec_ntb_exit);
diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c
index 807569e62bee..0666e33c305b 100644
--- a/drivers/pci/switch/switchtec.c
+++ b/drivers/pci/switch/switchtec.c
@@ -1275,6 +1275,9 @@ static int switchtec_pci_probe(struct pci_dev *pdev,
struct switchtec_dev *stdev;
int rc;

+ if (pdev->class == MICROSEMI_NTB_CLASSCODE)
+ request_module_nowait("switchtec_ntb");
+
stdev = stdev_create(pdev);
if (IS_ERR(stdev))
return PTR_ERR(stdev);
diff --git a/include/linux/switchtec.h b/include/linux/switchtec.h
index d8159944f013..09d73d0d1aa8 100644
--- a/include/linux/switchtec.h
+++ b/include/linux/switchtec.h
@@ -320,6 +320,8 @@ struct pff_csr_regs {
u32 reserved4[174];
} __packed;

+struct switchtec_ntb;
+
struct switchtec_dev {
struct pci_dev *pdev;
struct device dev;
@@ -357,6 +359,8 @@ struct switchtec_dev {
struct work_struct link_event_work;
void (*link_notifier)(struct switchtec_dev *stdev);
u8 link_event_count[SWITCHTEC_MAX_PFF_CSR];
+
+ struct switchtec_ntb *sndev;
};

static inline struct switchtec_dev *to_stdev(struct device *dev)
--
2.11.0