arch/tile: provide kernel support for the tilegx TRIO shim

Provide kernel support for the tilegx "Transaction I/O" (TRIO) on-chip
hardware.  This hardware implements the PCIe interface for tilegx;
the driver changes to use TRIO for PCIe are in a subsequent commit.

The change is layered on top of the tilegx GXIO IORPC subsystem.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

1 files changed, 298 insertions, 0 deletions

diff --git a/arch/tile/include/gxio/trio.h b/arch/tile/include/gxio/trio.h
new file mode 100644
index 000000000000..77b80cdd46d8
--- /dev/null
+++ b/arch/tile/include/gxio/trio.h
@@ -0,0 +1,298 @@
+/*
+ * Copyright 2012 Tilera Corporation. All Rights Reserved.
+ *
+ *   This program is free software; you can redistribute it and/or
+ *   modify it under the terms of the GNU General Public License
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   This program is distributed in the hope that it will be useful, but
+ *   WITHOUT ANY WARRANTY; without even the implied warranty of
+ *   MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+/*
+ *
+ * An API for allocating, configuring, and manipulating TRIO hardware
+ * resources
+ */
+
+/*
+ *
+ * The TILE-Gx TRIO shim provides connections to external devices via
+ * PCIe or other transaction IO standards.  The gxio_trio_ API,
+ * declared in <gxio/trio.h>, allows applications to allocate and
+ * configure TRIO IO resources like DMA command rings, memory map
+ * windows, and device interrupts.  The following sections introduce
+ * the various components of the API.  We strongly recommend reading
+ * the TRIO section of the IO Device Guide (UG404) before working with
+ * this API.
+ *
+ * @section trio__ingress TRIO Ingress Hardware Resources
+ *
+ * The TRIO ingress hardware is responsible for examining incoming
+ * PCIe or StreamIO packets and choosing a processing mechanism based
+ * on the packets' bus address.  The gxio_trio_ API can be used to
+ * configure different handlers for different ranges of bus address
+ * space.  The user can configure "mapped memory" and "scatter queue"
+ * regions to match incoming packets within 4kB-aligned ranges of bus
+ * addresses.  Each range specifies a different set of mapping
+ * parameters to be applied when handling the ingress packet.  The
+ * following sections describe how to work with MapMem and scatter
+ * queue regions.
+ *
+ * @subsection trio__mapmem TRIO MapMem Regions
+ *
+ * TRIO mapped memory (or MapMem) regions allow the user to map
+ * incoming read and write requests directly to the application's
+ * memory space.  MapMem regions are allocated via
+ * gxio_trio_alloc_memory_maps().  Given an integer MapMem number,
+ * applications can use gxio_trio_init_memory_map() to specify the
+ * range of bus addresses that will match the region and the range of
+ * virtual addresses to which those packets will be applied.
+ *
+ * As with many other gxio APIs, the programmer must be sure to
+ * register memory pages that will be used with MapMem regions.  Pages
+ * can be registered with TRIO by allocating an ASID (address space
+ * identifier) and then using gxio_trio_register_page() to register up to
+ * 16 pages with the hardware.  The initialization functions for
+ * resources that require registered memory (MapMem, scatter queues,
+ * push DMA, and pull DMA) then take an 'asid' parameter in order to
+ * configure which set of registered pages is used by each resource.
+ *
+ * @subsection trio__scatter_queue TRIO Scatter Queues
+ *
+ * The TRIO shim's scatter queue regions allow users to dynamically
+ * map buffers from a large address space into a small range of bus
+ * addresses.  This is particularly helpful for PCIe endpoint devices,
+ * where the host generally limits the size of BARs to tens of
+ * megabytes.
+ *
+ * Each scatter queue consists of a memory map region, a queue of
+ * tile-side buffer VAs to be mapped to that region, and a bus-mapped
+ * "doorbell" register that the remote endpoint can write to trigger a
+ * dequeue of the current buffer VA, thus swapping in a new buffer.
+ * The VAs pushed onto a scatter queue must be 4kB aligned, so
+ * applications may need to use higher-level protocols to inform
+ * remote entities that they should apply some additional, sub-4kB
+ * offset when reading or writing the scatter queue region.  For more
+ * information, see the IO Device Guide (UG404).
+ *
+ * @section trio__egress TRIO Egress Hardware Resources
+ *
+ * The TRIO shim supports two mechanisms for egress packet generation:
+ * programmed IO (PIO) and push/pull DMA.  PIO allows applications to
+ * create MMIO mappings for PCIe or StreamIO address space, such that
+ * the application can generate word-sized read or write transactions
+ * by issuing load or store instructions.  Push and pull DMA are tuned
+ * for larger transactions; they use specialized hardware engines to
+ * transfer large blocks of data at line rate.
+ *
+ * @subsection trio__pio TRIO Programmed IO
+ *
+ * Programmed IO allows applications to create MMIO mappings for PCIe
+ * or StreamIO address space.  The hardware PIO regions support access
+ * to PCIe configuration, IO, and memory space, but the gxio_trio API
+ * only supports memory space accesses.  PIO regions are allocated
+ * with gxio_trio_alloc_pio_regions() and initialized via
+ * gxio_trio_init_pio_region().  Once a region is bound to a range of
+ * bus address via the initialization function, the application can
+ * use gxio_trio_map_pio_region() to create MMIO mappings from its VA
+ * space onto the range of bus addresses supported by the PIO region.
+ *
+ * @subsection trio_dma TRIO Push and Pull DMA
+ *
+ * The TRIO push and pull DMA engines allow users to copy blocks of
+ * data between application memory and the bus.  Push DMA generates
+ * write packets that copy from application memory to the bus and pull
+ * DMA generates read packets that copy from the bus into application
+ * memory.  The DMA engines are managed via an API that is very
+ * similar to the mPIPE eDMA interface.  For a detailed explanation of
+ * the eDMA queue API, see @ref gxio_mpipe_wrappers.
+ *
+ * Push and pull DMA queues are allocated via
+ * gxio_trio_alloc_push_dma_ring() / gxio_trio_alloc_pull_dma_ring().
+ * Once allocated, users generally use a ::gxio_trio_dma_queue_t
+ * object to manage the queue, providing easy wrappers for reserving
+ * command slots in the DMA command ring, filling those slots, and
+ * waiting for commands to complete.  DMA queues can be initialized
+ * via gxio_trio_init_push_dma_queue() or
+ * gxio_trio_init_pull_dma_queue().
+ *
+ * See @ref trio/push_dma/app.c for an example of how to use push DMA.
+ *
+ * @section trio_shortcomings Plans for Future API Revisions
+ *
+ * The simulation framework is incomplete.  Future features include:
+ *
+ * - Support for reset and deallocation of resources.
+ *
+ * - Support for pull DMA.
+ *
+ * - Support for interrupt regions and user-space interrupt delivery.
+ *
+ * - Support for getting BAR mappings and reserving regions of BAR
+ *   address space.
+ */
+#ifndef _GXIO_TRIO_H_
+#define _GXIO_TRIO_H_
+
+#include <linux/types.h>
+
+#include "common.h"
+#include "dma_queue.h"
+
+#include <arch/trio_constants.h>
+#include <arch/trio.h>
+#include <arch/trio_pcie_intfc.h>
+#include <arch/trio_pcie_rc.h>
+#include <arch/trio_shm.h>
+#include <hv/drv_trio_intf.h>
+#include <hv/iorpc.h>
+
+/* A context object used to manage TRIO hardware resources. */
+typedef struct {
+
+        /* File descriptor for calling up to Linux (and thus the HV). */
+        int fd;
+
+        /* The VA at which the MAC MMIO registers are mapped. */
+        char *mmio_base_mac;
+
+        /* The VA at which the PIO config space are mapped for each PCIe MAC.
+           Gx36 has max 3 PCIe MACs per TRIO shim. */
+        char *mmio_base_pio_cfg[TILEGX_TRIO_PCIES];
+
+#ifdef USE_SHARED_PCIE_CONFIG_REGION
+        /* Index of the shared PIO region for PCI config access. */
+        int pio_cfg_index;
+#else
+        /* Index of the PIO region for PCI config access per MAC. */
+        int pio_cfg_index[TILEGX_TRIO_PCIES];
+#endif
+
+        /*  The VA at which the push DMA MMIO registers are mapped. */
+        char *mmio_push_dma[TRIO_NUM_PUSH_DMA_RINGS];
+
+        /*  The VA at which the pull DMA MMIO registers are mapped. */
+        char *mmio_pull_dma[TRIO_NUM_PUSH_DMA_RINGS];
+
+        /* Application space ID. */
+        unsigned int asid;
+
+} gxio_trio_context_t;
+
+/* Command descriptor for push or pull DMA. */
+typedef TRIO_DMA_DESC_t gxio_trio_dma_desc_t;
+
+/* A convenient, thread-safe interface to an eDMA ring. */
+typedef struct {
+
+        /* State object for tracking head and tail pointers. */
+        __gxio_dma_queue_t dma_queue;
+
+        /* The ring entries. */
+        gxio_trio_dma_desc_t *dma_descs;
+
+        /* The number of entries minus one. */
+        unsigned long mask_num_entries;
+
+        /* The log2() of the number of entries. */
+        unsigned int log2_num_entries;
+
+} gxio_trio_dma_queue_t;
+
+/* Initialize a TRIO context.
+ *
+ * This function allocates a TRIO "service domain" and maps the MMIO
+ * registers into the the caller's VA space.
+ *
+ * @param trio_index Which TRIO shim; Gx36 must pass 0.
+ * @param context Context object to be initialized.
+ */
+extern int gxio_trio_init(gxio_trio_context_t *context,
+                          unsigned int trio_index);
+
+/* This indicates that an ASID hasn't been allocated. */
+#define GXIO_ASID_NULL -1
+
+/* Ordering modes for map memory regions and scatter queue regions. */
+typedef enum gxio_trio_order_mode_e {
+        /* Writes are not ordered.  Reads always wait for previous writes. */
+        GXIO_TRIO_ORDER_MODE_UNORDERED =
+                TRIO_MAP_MEM_SETUP__ORDER_MODE_VAL_UNORDERED,
+        /* Both writes and reads wait for previous transactions to complete. */
+        GXIO_TRIO_ORDER_MODE_STRICT =
+                TRIO_MAP_MEM_SETUP__ORDER_MODE_VAL_STRICT,
+        /* Writes are ordered unless the incoming packet has the
+           relaxed-ordering attributes set. */
+        GXIO_TRIO_ORDER_MODE_OBEY_PACKET =
+                TRIO_MAP_MEM_SETUP__ORDER_MODE_VAL_REL_ORD
+} gxio_trio_order_mode_t;
+
+/* Initialize a memory mapping region.
+ *
+ * @param context An initialized TRIO context.
+ * @param map A Memory map region allocated by gxio_trio_alloc_memory_map().
+ * @param target_mem VA of backing memory, should be registered via
+ *   gxio_trio_register_page() and aligned to 4kB.
+ * @param target_size Length of the memory mapping, must be a multiple
+ * of 4kB.
+ * @param asid ASID to be used for Tile-side address translation.
+ * @param mac MAC number.
+ * @param bus_address Bus address at which the mapping starts.
+ * @param order_mode Memory ordering mode for this mapping.
+ * @return Zero on success, else ::GXIO_TRIO_ERR_BAD_MEMORY_MAP,
+ * GXIO_TRIO_ERR_BAD_ASID, or ::GXIO_TRIO_ERR_BAD_BUS_RANGE.
+ */
+extern int gxio_trio_init_memory_map(gxio_trio_context_t *context,
+                                     unsigned int map, void *target_mem,
+                                     size_t target_size, unsigned int asid,
+                                     unsigned int mac, uint64_t bus_address,
+                                     gxio_trio_order_mode_t order_mode);
+
+/* Flags that can be passed to resource allocation functions. */
+enum gxio_trio_alloc_flags_e {
+        GXIO_TRIO_ALLOC_FIXED = HV_TRIO_ALLOC_FIXED,
+};
+
+/* Flags that can be passed to memory registration functions. */
+enum gxio_trio_mem_flags_e {
+        /* Do not fill L3 when writing, and invalidate lines upon egress. */
+        GXIO_TRIO_MEM_FLAG_NT_HINT = IORPC_MEM_BUFFER_FLAG_NT_HINT,
+
+        /* L3 cache fills should only populate IO cache ways. */
+        GXIO_TRIO_MEM_FLAG_IO_PIN = IORPC_MEM_BUFFER_FLAG_IO_PIN,
+};
+
+/* Flag indicating a request generator uses a special traffic
+    class. */
+#define GXIO_TRIO_FLAG_TRAFFIC_CLASS(N) HV_TRIO_FLAG_TC(N)
+
+/* Flag indicating a request generator uses a virtual function
+    number. */
+#define GXIO_TRIO_FLAG_VFUNC(N) HV_TRIO_FLAG_VFUNC(N)
+
+/*****************************************************************
+ *                       Memory Registration                      *
+ ******************************************************************/
+
+/* Allocate Application Space Identifiers (ASIDs).  Each ASID can
+ * register up to 16 page translations.  ASIDs are used by memory map
+ * regions, scatter queues, and DMA queues to translate application
+ * VAs into memory system PAs.
+ *
+ * @param context An initialized TRIO context.
+ * @param count Number of ASIDs required.
+ * @param first Index of first ASID if ::GXIO_TRIO_ALLOC_FIXED flag
+ *   is set, otherwise ignored.
+ * @param flags Flag bits, including bits from ::gxio_trio_alloc_flags_e.
+ * @return Index of first ASID, or ::GXIO_TRIO_ERR_NO_ASID if allocation
+ *   failed.
+ */
+extern int gxio_trio_alloc_asids(gxio_trio_context_t *context,
+                                 unsigned int count, unsigned int first,
+                                 unsigned int flags);
+
+#endif /* ! _GXIO_TRIO_H_ */