PCI-Express Non-Transparent Bridge Support

A PCI-Express non-transparent bridge (NTB) is a point-to-point PCIe bus
connecting 2 systems, providing electrical isolation between the two subsystems.
A non-transparent bridge is functionally similar to a transparent bridge except
that both sides of the bridge have their own independent address domains.  The
host on one side of the bridge will not have the visibility of the complete
memory or I/O space on the other side of the bridge.  To communicate across the
non-transparent bridge, each NTB endpoint has one (or more) apertures exposed to
the local system.  Writes to these apertures are mirrored to memory on the
remote system.  Communications can also occur through the use of doorbell
registers that initiate interrupts to the alternate domain, and scratch-pad
registers accessible from both sides.

The NTB device driver is needed to configure these memory windows, doorbell, and
scratch-pad registers as well as use them in such a way as they can be turned
into a viable communication channel to the remote system.  ntb_hw.[ch]
determines the usage model (NTB to NTB or NTB to Root Port) and abstracts away
the underlying hardware to provide access and a common interface to the doorbell
registers, scratch pads, and memory windows.  These hardware interfaces are
exported so that other, non-mainlined kernel drivers can access these.
ntb_transport.[ch] also uses the exported interfaces in ntb_hw.[ch] to setup a
communication channel(s) and provide a reliable way of transferring data from
one side to the other, which it then exports so that "client" drivers can access
them.  These client drivers are used to provide a standard kernel interface
(i.e., Ethernet device) to NTB, such that Linux can transfer data from one
system to the other in a standard way.

Signed-off-by: Jon Mason <jon.mason@intel.com>
Reviewed-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 181 insertions, 0 deletions

diff --git a/drivers/ntb/ntb_hw.h b/drivers/ntb/ntb_hw.h
new file mode 100644
index 000000000000..5e009519c64f
--- /dev/null
+++ b/drivers/ntb/ntb_hw.h
@@ -0,0 +1,181 @@
+/*
+ * This file is provided under a dual BSD/GPLv2 license.  When using or
+ *   redistributing this file, you may do so under either license.
+ *
+ *   GPL LICENSE SUMMARY
+ *
+ *   Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of version 2 of the GNU General Public License as
+ *   published by the Free Software Foundation.
+ *
+ *   BSD LICENSE
+ *
+ *   Copyright(c) 2012 Intel Corporation. All rights reserved.
+ *
+ *   Redistribution and use in source and binary forms, with or without
+ *   modification, are permitted provided that the following conditions
+ *   are met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copy
+ *       notice, this list of conditions and the following disclaimer in
+ *       the documentation and/or other materials provided with the
+ *       distribution.
+ *     * Neither the name of Intel Corporation nor the names of its
+ *       contributors may be used to endorse or promote products derived
+ *       from this software without specific prior written permission.
+ *
+ *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Intel PCIe NTB Linux driver
+ *
+ * Contact Information:
+ * Jon Mason <jon.mason@intel.com>
+ */
+
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_JSF		0x3725
+#define PCI_DEVICE_ID_INTEL_NTB_CLASSIC_JSF	0x3726
+#define PCI_DEVICE_ID_INTEL_NTB_RP_JSF		0x3727
+#define PCI_DEVICE_ID_INTEL_NTB_RP_SNB		0x3C08
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_SNB		0x3C0D
+#define PCI_DEVICE_ID_INTEL_NTB_CLASSIC_SNB	0x3C0E
+#define PCI_DEVICE_ID_INTEL_NTB_2ND_SNB		0x3C0F
+#define PCI_DEVICE_ID_INTEL_NTB_B2B_BWD		0x0C4E
+
+#define msix_table_size(control)	((control & PCI_MSIX_FLAGS_QSIZE)+1)
+
+#define NTB_BAR_MMIO		0
+#define NTB_BAR_23		2
+#define NTB_BAR_45		4
+#define NTB_BAR_MASK		((1 << NTB_BAR_MMIO) | (1 << NTB_BAR_23) |\
+				 (1 << NTB_BAR_45))
+
+#define NTB_LINK_DOWN		0
+#define NTB_LINK_UP		1
+
+#define NTB_HB_TIMEOUT		msecs_to_jiffies(1000)
+
+#define NTB_NUM_MW		2
+
+enum ntb_hw_event {
+	NTB_EVENT_SW_EVENT0 = 0,
+	NTB_EVENT_SW_EVENT1,
+	NTB_EVENT_SW_EVENT2,
+	NTB_EVENT_HW_ERROR,
+	NTB_EVENT_HW_LINK_UP,
+	NTB_EVENT_HW_LINK_DOWN,
+};
+
+struct ntb_mw {
+	dma_addr_t phys_addr;
+	void __iomem *vbase;
+	resource_size_t bar_sz;
+};
+
+struct ntb_db_cb {
+	void (*callback) (void *data, int db_num);
+	unsigned int db_num;
+	void *data;
+	struct ntb_device *ndev;
+};
+
+struct ntb_device {
+	struct pci_dev *pdev;
+	struct msix_entry *msix_entries;
+	void __iomem *reg_base;
+	struct ntb_mw mw[NTB_NUM_MW];
+	struct {
+		unsigned int max_spads;
+		unsigned int max_db_bits;
+		unsigned int msix_cnt;
+	} limits;
+	struct {
+		void __iomem *pdb;
+		void __iomem *pdb_mask;
+		void __iomem *sdb;
+		void __iomem *sbar2_xlat;
+		void __iomem *sbar4_xlat;
+		void __iomem *spad_write;
+		void __iomem *spad_read;
+		void __iomem *lnk_cntl;
+		void __iomem *lnk_stat;
+		void __iomem *spci_cmd;
+	} reg_ofs;
+	struct ntb_transport *ntb_transport;
+	void (*event_cb)(void *handle, enum ntb_hw_event event);
+
+	struct ntb_db_cb *db_cb;
+	unsigned char hw_type;
+	unsigned char conn_type;
+	unsigned char dev_type;
+	unsigned char num_msix;
+	unsigned char bits_per_vector;
+	unsigned char max_cbs;
+	unsigned char link_status;
+	struct delayed_work hb_timer;
+	unsigned long last_ts;
+};
+
+/**
+ * ntb_hw_link_status() - return the hardware link status
+ * @ndev: pointer to ntb_device instance
+ *
+ * Returns true if the hardware is connected to the remote system
+ *
+ * RETURNS: true or false based on the hardware link state
+ */
+static inline bool ntb_hw_link_status(struct ntb_device *ndev)
+{
+	return ndev->link_status == NTB_LINK_UP;
+}
+
+/**
+ * ntb_query_pdev() - return the pci_dev pointer
+ * @ndev: pointer to ntb_device instance
+ *
+ * Given the ntb pointer return the pci_dev pointerfor the NTB hardware device
+ *
+ * RETURNS: a pointer to the ntb pci_dev
+ */
+static inline struct pci_dev *ntb_query_pdev(struct ntb_device *ndev)
+{
+	return ndev->pdev;
+}
+
+struct ntb_device *ntb_register_transport(struct pci_dev *pdev,
+					  void *transport);
+void ntb_unregister_transport(struct ntb_device *ndev);
+void ntb_set_mw_addr(struct ntb_device *ndev, unsigned int mw, u64 addr);
+int ntb_register_db_callback(struct ntb_device *ndev, unsigned int idx,
+			     void *data, void (*db_cb_func) (void *data,
+							     int db_num));
+void ntb_unregister_db_callback(struct ntb_device *ndev, unsigned int idx);
+int ntb_register_event_callback(struct ntb_device *ndev,
+				void (*event_cb_func) (void *handle,
+						       unsigned int event));
+void ntb_unregister_event_callback(struct ntb_device *ndev);
+int ntb_get_max_spads(struct ntb_device *ndev);
+int ntb_write_local_spad(struct ntb_device *ndev, unsigned int idx, u32 val);
+int ntb_read_local_spad(struct ntb_device *ndev, unsigned int idx, u32 *val);
+int ntb_write_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 val);
+int ntb_read_remote_spad(struct ntb_device *ndev, unsigned int idx, u32 *val);
+void *ntb_get_mw_vbase(struct ntb_device *ndev, unsigned int mw);
+resource_size_t ntb_get_mw_size(struct ntb_device *ndev, unsigned int mw);
+void ntb_ring_sdb(struct ntb_device *ndev, unsigned int idx);
+void *ntb_find_transport(struct pci_dev *pdev);
+
+int ntb_transport_init(struct pci_dev *pdev);
+void ntb_transport_free(void *transport);