soc: qcom: ipa: GSI headers

The Generic Software Interface is a layer of the IPA driver that
abstracts the underlying hardware.  The next patch includes the
main code for GSI (including some additional documentation).  This
patch just includes three GSI header files.

  - "gsi.h" is the top-level GSI header file.  This structure is
    is embedded within the IPA structure.  The main abstraction
    implemented by the GSI code is the channel, and this header
    exposes several operations that can be performed on a GSI channel.

  - "gsi_private.h" exposes some definitions that are intended to be
    private, used only by the main GSI code and the GSI transaction
    code (defined in an upcoming patch).

  - Like "ipa_reg.h", "gsi_reg.h" defines the offsets of the 32-bit
    registers used by the GSI layer, along with masks that define the
    position and width of fields less than 32 bits located within
    these registers.
Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ipa/gsi.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.
+ * Copyright (C) 2018-2020 Linaro Ltd.
+ */
+#ifndef _GSI_H_
+#define _GSI_H_
+
+#include <linux/types.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+#include <linux/completion.h>
+#include <linux/platform_device.h>
+#include <linux/netdevice.h>
+
+/* Maximum number of channels and event rings supported by the driver */
+#define GSI_CHANNEL_COUNT_MAX	17
+#define GSI_EVT_RING_COUNT_MAX	13
+
+/* Maximum TLV FIFO size for a channel; 64 here is arbitrary (and high) */
+#define GSI_TLV_MAX		64
+
+struct device;
+struct scatterlist;
+struct platform_device;
+
+struct gsi;
+struct gsi_trans;
+struct gsi_channel_data;
+struct ipa_gsi_endpoint_data;
+
+/* Execution environment IDs */
+enum gsi_ee_id {
+	GSI_EE_AP	= 0,
+	GSI_EE_MODEM	= 1,
+	GSI_EE_UC	= 2,
+	GSI_EE_TZ	= 3,
+};
+
+struct gsi_ring {
+	void *virt;			/* ring array base address */
+	dma_addr_t addr;		/* primarily low 32 bits used */
+	u32 count;			/* number of elements in ring */
+
+	/* The ring index value indicates the next "open" entry in the ring.
+	 *
+	 * A channel ring consists of TRE entries filled by the AP and passed
+	 * to the hardware for processing.  For a channel ring, the ring index
+	 * identifies the next unused entry to be filled by the AP.
+	 *
+	 * An event ring consists of event structures filled by the hardware
+	 * and passed to the AP.  For event rings, the ring index identifies
+	 * the next ring entry that is not known to have been filled by the
+	 * hardware.
+	 */
+	u32 index;
+};
+
+/* Transactions use several resources that can be allocated dynamically
+ * but taken from a fixed-size pool.  The number of elements required for
+ * the pool is limited by the total number of TREs that can be outstanding.
+ *
+ * If sufficient TREs are available to reserve for a transaction,
+ * allocation from these pools is guaranteed to succeed.  Furthermore,
+ * these resources are implicitly freed whenever the TREs in the
+ * transaction they're associated with are released.
+ *
+ * The result of a pool allocation of multiple elements is always
+ * contiguous.
+ */
+struct gsi_trans_pool {
+	void *base;			/* base address of element pool */
+	u32 count;			/* # elements in the pool */
+	u32 free;			/* next free element in pool (modulo) */
+	u32 size;			/* size (bytes) of an element */
+	u32 max_alloc;			/* max allocation request */
+	dma_addr_t addr;		/* DMA address if DMA pool (or 0) */
+};
+
+struct gsi_trans_info {
+	atomic_t tre_avail;		/* TREs available for allocation */
+	struct gsi_trans_pool pool;	/* transaction pool */
+	struct gsi_trans_pool sg_pool;	/* scatterlist pool */
+	struct gsi_trans_pool cmd_pool;	/* command payload DMA pool */
+	struct gsi_trans_pool info_pool;/* command information pool */
+	struct gsi_trans **map;		/* TRE -> transaction map */
+
+	spinlock_t spinlock;		/* protects updates to the lists */
+	struct list_head alloc;		/* allocated, not committed */
+	struct list_head pending;	/* committed, awaiting completion */
+	struct list_head complete;	/* completed, awaiting poll */
+	struct list_head polled;	/* returned by gsi_channel_poll_one() */
+};
+
+/* Hardware values signifying the state of a channel */
+enum gsi_channel_state {
+	GSI_CHANNEL_STATE_NOT_ALLOCATED	= 0x0,
+	GSI_CHANNEL_STATE_ALLOCATED	= 0x1,
+	GSI_CHANNEL_STATE_STARTED	= 0x2,
+	GSI_CHANNEL_STATE_STOPPED	= 0x3,
+	GSI_CHANNEL_STATE_STOP_IN_PROC	= 0x4,
+	GSI_CHANNEL_STATE_ERROR		= 0xf,
+};
+
+/* We only care about channels between IPA and AP */
+struct gsi_channel {
+	struct gsi *gsi;
+	bool toward_ipa;
+	bool command;			/* AP command TX channel or not */
+	bool use_prefetch;		/* use prefetch (else escape buf) */
+
+	u8 tlv_count;			/* # entries in TLV FIFO */
+	u16 tre_count;
+	u16 event_count;
+
+	struct completion completion;	/* signals channel state changes */
+	enum gsi_channel_state state;
+
+	struct gsi_ring tre_ring;
+	u32 evt_ring_id;
+
+	u64 byte_count;			/* total # bytes transferred */
+	u64 trans_count;		/* total # transactions */
+	/* The following counts are used only for TX endpoints */
+	u64 queued_byte_count;		/* last reported queued byte count */
+	u64 queued_trans_count;		/* ...and queued trans count */
+	u64 compl_byte_count;		/* last reported completed byte count */
+	u64 compl_trans_count;		/* ...and completed trans count */
+
+	struct gsi_trans_info trans_info;
+
+	struct napi_struct napi;
+};
+
+/* Hardware values signifying the state of an event ring */
+enum gsi_evt_ring_state {
+	GSI_EVT_RING_STATE_NOT_ALLOCATED	= 0x0,
+	GSI_EVT_RING_STATE_ALLOCATED		= 0x1,
+	GSI_EVT_RING_STATE_ERROR		= 0xf,
+};
+
+struct gsi_evt_ring {
+	struct gsi_channel *channel;
+	struct completion completion;	/* signals event ring state changes */
+	enum gsi_evt_ring_state state;
+	struct gsi_ring ring;
+};
+
+struct gsi {
+	struct device *dev;		/* Same as IPA device */
+	struct net_device dummy_dev;	/* needed for NAPI */
+	void __iomem *virt;
+	u32 irq;
+	bool irq_wake_enabled;
+	u32 channel_count;
+	u32 evt_ring_count;
+	struct gsi_channel channel[GSI_CHANNEL_COUNT_MAX];
+	struct gsi_evt_ring evt_ring[GSI_EVT_RING_COUNT_MAX];
+	u32 event_bitmap;
+	u32 event_enable_bitmap;
+	u32 modem_channel_bitmap;
+	struct completion completion;	/* for global EE commands */
+	struct mutex mutex;		/* protects commands, programming */
+};
+
+/**
+ * gsi_setup() - Set up the GSI subsystem
+ * @gsi:	Address of GSI structure embedded in an IPA structure
+ * @db_enable:	Whether to use the GSI doorbell engine
+ *
+ * @Return:	0 if successful, or a negative error code
+ *
+ * Performs initialization that must wait until the GSI hardware is
+ * ready (including firmware loaded).
+ */
+int gsi_setup(struct gsi *gsi, bool db_enable);
+
+/**
+ * gsi_teardown() - Tear down GSI subsystem
+ * @gsi:	GSI address previously passed to a successful gsi_setup() call
+ */
+void gsi_teardown(struct gsi *gsi);
+
+/**
+ * gsi_channel_tre_max() - Channel maximum number of in-flight TREs
+ * @gsi:	GSI pointer
+ * @channel_id:	Channel whose limit is to be returned
+ *
+ * @Return:	 The maximum number of TREs oustanding on the channel
+ */
+u32 gsi_channel_tre_max(struct gsi *gsi, u32 channel_id);
+
+/**
+ * gsi_channel_trans_tre_max() - Maximum TREs in a single transaction
+ * @gsi:	GSI pointer
+ * @channel_id:	Channel whose limit is to be returned
+ *
+ * @Return:	 The maximum TRE count per transaction on the channel
+ */
+u32 gsi_channel_trans_tre_max(struct gsi *gsi, u32 channel_id);
+
+/**
+ * gsi_channel_start() - Start an allocated GSI channel
+ * @gsi:	GSI pointer
+ * @channel_id:	Channel to start
+ *
+ * @Return:	0 if successful, or a negative error code
+ */
+int gsi_channel_start(struct gsi *gsi, u32 channel_id);
+
+/**
+ * gsi_channel_stop() - Stop a started GSI channel
+ * @gsi:	GSI pointer returned by gsi_setup()
+ * @channel_id:	Channel to stop
+ *
+ * @Return:	0 if successful, or a negative error code
+ */
+int gsi_channel_stop(struct gsi *gsi, u32 channel_id);
+
+/**
+ * gsi_channel_reset() - Reset an allocated GSI channel
+ * @gsi:	GSI pointer
+ * @channel_id:	Channel to be reset
+ * @db_enable:	Whether doorbell engine should be enabled
+ *
+ * Reset a channel and reconfigure it.  The @db_enable flag indicates
+ * whether the doorbell engine will be enabled following reconfiguration.
+ *
+ * GSI hardware relinquishes ownership of all pending receive buffer
+ * transactions and they will complete with their cancelled flag set.
+ */
+void gsi_channel_reset(struct gsi *gsi, u32 channel_id, bool db_enable);
+
+int gsi_channel_suspend(struct gsi *gsi, u32 channel_id, bool stop);
+int gsi_channel_resume(struct gsi *gsi, u32 channel_id, bool start);
+
+/**
+ * gsi_init() - Initialize the GSI subsystem
+ * @gsi:	Address of GSI structure embedded in an IPA structure
+ * @pdev:	IPA platform device
+ *
+ * @Return:	0 if successful, or a negative error code
+ *
+ * Early stage initialization of the GSI subsystem, performing tasks
+ * that can be done before the GSI hardware is ready to use.
+ */
+int gsi_init(struct gsi *gsi, struct platform_device *pdev, bool prefetch,
+	     u32 count, const struct ipa_gsi_endpoint_data *data,
+	     bool modem_alloc);
+
+/**
+ * gsi_exit() - Exit the GSI subsystem
+ * @gsi:	GSI address previously passed to a successful gsi_init() call
+ */
+void gsi_exit(struct gsi *gsi);
+
+#endif /* _GSI_H_ */

drivers/net/ipa/gsi_private.h

+/* SPDX-License-Identifier: GPL-2.0 */
+
+/* Copyright (c) 2015-2018, The Linux Foundation. All rights reserved.
+ * Copyright (C) 2018-2020 Linaro Ltd.
+ */
+#ifndef _GSI_PRIVATE_H_
+#define _GSI_PRIVATE_H_
+
+/* === Only "gsi.c" and "gsi_trans.c" should include this file === */
+
+#include <linux/types.h>
+
+struct gsi_trans;
+struct gsi_ring;
+struct gsi_channel;
+
+#define GSI_RING_ELEMENT_SIZE	16	/* bytes */
+
+/* Return the entry that follows one provided in a transaction pool */
+void *gsi_trans_pool_next(struct gsi_trans_pool *pool, void *element);
+
+/**
+ * gsi_trans_move_complete() - Mark a GSI transaction completed
+ * @trans:	Transaction to commit
+ */
+void gsi_trans_move_complete(struct gsi_trans *trans);
+
+/**
+ * gsi_trans_move_polled() - Mark a transaction polled
+ * @trans:	Transaction to update
+ */
+void gsi_trans_move_polled(struct gsi_trans *trans);
+
+/**
+ * gsi_trans_complete() - Complete a GSI transaction
+ * @trans:	Transaction to complete
+ *
+ * Marks a transaction complete (including freeing it).
+ */
+void gsi_trans_complete(struct gsi_trans *trans);
+
+/**
+ * gsi_channel_trans_mapped() - Return a transaction mapped to a TRE index
+ * @channel:	Channel associated with the transaction
+ * @index:	Index of the TRE having a transaction
+ *
+ * @Return:	The GSI transaction pointer associated with the TRE index
+ */
+struct gsi_trans *gsi_channel_trans_mapped(struct gsi_channel *channel,
+					   u32 index);
+
+/**
+ * gsi_channel_trans_complete() - Return a channel's next completed transaction
+ * @channel:	Channel whose next transaction is to be returned
+ *
+ * @Return:	The next completed transaction, or NULL if nothing new
+ */
+struct gsi_trans *gsi_channel_trans_complete(struct gsi_channel *channel);
+
+/**
+ * gsi_channel_trans_cancel_pending() - Cancel pending transactions
+ * @channel:	Channel whose pending transactions should be cancelled
+ *
+ * Cancel all pending transactions on a channel.  These are transactions
+ * that have been committed but not yet completed.  This is required when
+ * the channel gets reset.  At that time all pending transactions will be
+ * marked as cancelled.
+ *
+ * NOTE:  Transactions already complete at the time of this call are
+ *	  unaffected.
+ */
+void gsi_channel_trans_cancel_pending(struct gsi_channel *channel);
+
+/**
+ * gsi_channel_trans_init() - Initialize a channel's GSI transaction info
+ * @gsi:	GSI pointer
+ * @channel_id:	Channel number
+ *
+ * @Return:	0 if successful, or -ENOMEM on allocation failure
+ *
+ * Creates and sets up information for managing transactions on a channel
+ */
+int gsi_channel_trans_init(struct gsi *gsi, u32 channel_id);
+
+/**
+ * gsi_channel_trans_exit() - Inverse of gsi_channel_trans_init()
+ * @channel:	Channel whose transaction information is to be cleaned up
+ */
+void gsi_channel_trans_exit(struct gsi_channel *channel);
+
+/**
+ * gsi_channel_doorbell() - Ring a channel's doorbell
+ * @channel:	Channel whose doorbell should be rung
+ *
+ * Rings a channel's doorbell to inform the GSI hardware that new
+ * transactions (TREs, really) are available for it to process.
+ */
+void gsi_channel_doorbell(struct gsi_channel *channel);
+
+/**
+ * gsi_ring_virt() - Return virtual address for a ring entry
+ * @ring:	Ring whose address is to be translated
+ * @addr:	Index (slot number) of entry
+ */
+void *gsi_ring_virt(struct gsi_ring *ring, u32 index);
+
+/**
+ * gsi_channel_tx_queued() - Report the number of bytes queued to hardware
+ * @channel:	Channel whose bytes have been queued
+ *
+ * This arranges for the the number of transactions and bytes for
+ * transfer that have been queued to hardware to be reported.  It
+ * passes this information up the network stack so it can be used to
+ * throttle transmissions.
+ */
+void gsi_channel_tx_queued(struct gsi_channel *channel);
+
+#endif /* _GSI_PRIVATE_H_ */