net: iosm: shared memory IPC interface

1) Initializes shared memory for host-device communication.
2) Allocate resources required for control & data operations.
3) Transfers the Device IRQ to IPC execution thread.
4) Defines the timer cbs for async events.
Signed-off-by: NM Chetan Kumar <m.chetan.kumar@intel.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/wwan/iosm/iosm_ipc_imem.h

+/* SPDX-License-Identifier: GPL-2.0-only
+ *
+ * Copyright (C) 2020-21 Intel Corporation.
+ */
+
+#ifndef IOSM_IPC_IMEM_H
+#define IOSM_IPC_IMEM_H
+
+#include <linux/skbuff.h>
+#include <stdbool.h>
+
+#include "iosm_ipc_mmio.h"
+#include "iosm_ipc_pcie.h"
+#include "iosm_ipc_uevent.h"
+#include "iosm_ipc_wwan.h"
+#include "iosm_ipc_task_queue.h"
+
+struct ipc_chnl_cfg;
+
+/* IRQ moderation in usec */
+#define IRQ_MOD_OFF 0
+#define IRQ_MOD_NET 1000
+#define IRQ_MOD_TRC 4000
+
+/* Either the PSI image is accepted by CP or the suspended flash tool is waken,
+ * informed that the CP ROM driver is not ready to process the PSI image.
+ * unit : milliseconds
+ */
+#define IPC_PSI_TRANSFER_TIMEOUT 3000
+
+/* Timeout in 20 msec to wait for the modem to boot up to
+ * IPC_MEM_DEVICE_IPC_INIT state.
+ * unit : milliseconds (500 * ipc_util_msleep(20))
+ */
+#define IPC_MODEM_BOOT_TIMEOUT 500
+
+/* Wait timeout for ipc status reflects IPC_MEM_DEVICE_IPC_UNINIT
+ * unit : milliseconds
+ */
+#define IPC_MODEM_UNINIT_TIMEOUT_MS 30
+
+/* Pending time for processing data.
+ * unit : milliseconds
+ */
+#define IPC_PEND_DATA_TIMEOUT 500
+
+/* The timeout in milliseconds for application to wait for remote time. */
+#define IPC_REMOTE_TS_TIMEOUT_MS 10
+
+/* Timeout for TD allocation retry.
+ * unit : milliseconds
+ */
+#define IPC_TD_ALLOC_TIMER_PERIOD_MS 100
+
+/* Host sleep target is host */
+#define IPC_HOST_SLEEP_HOST 0
+
+/* Host sleep target is device */
+#define IPC_HOST_SLEEP_DEVICE 1
+
+/* Sleep message, target host: AP enters sleep / target device: CP is
+ * allowed to enter sleep and shall use the host sleep protocol
+ */
+#define IPC_HOST_SLEEP_ENTER_SLEEP 0
+
+/* Sleep_message, target host: AP exits  sleep / target device: CP is
+ * NOT allowed to enter sleep
+ */
+#define IPC_HOST_SLEEP_EXIT_SLEEP 1
+
+#define IMEM_IRQ_DONT_CARE (-1)
+
+#define IPC_MEM_MAX_CHANNELS 7
+
+#define IPC_MEM_MUX_IP_SESSION_ENTRIES 8
+
+#define IPC_MEM_MUX_IP_CH_IF_ID 0
+
+#define TD_UPDATE_DEFAULT_TIMEOUT_USEC 1900
+
+#define FORCE_UPDATE_DEFAULT_TIMEOUT_USEC 500
+
+/* Sleep_message, target host: not applicable  / target device: CP is
+ * allowed to enter sleep and shall NOT use the device sleep protocol
+ */
+#define IPC_HOST_SLEEP_ENTER_SLEEP_NO_PROTOCOL 2
+
+/* in_band_crash_signal IPC_MEM_INBAND_CRASH_SIG
+ * Modem crash notification configuration. If this value is non-zero then
+ * FEATURE_SET message will be sent to the Modem as a result the Modem will
+ * signal Crash via Execution Stage register. If this value is zero then Modem
+ * will use out-of-band method to notify about it's Crash.
+ */
+#define IPC_MEM_INBAND_CRASH_SIG 1
+
+/* Extra headroom to be allocated for DL SKBs to allow addition of Ethernet
+ * header
+ */
+#define IPC_MEM_DL_ETH_OFFSET 16
+
+#define IPC_CB(skb) ((struct ipc_skb_cb *)((skb)->cb))
+
+#define FULLY_FUNCTIONAL 0
+
+/* List of the supported UL/DL pipes. */
+enum ipc_mem_pipes {
+	IPC_MEM_PIPE_0 = 0,
+	IPC_MEM_PIPE_1,
+	IPC_MEM_PIPE_2,
+	IPC_MEM_PIPE_3,
+	IPC_MEM_PIPE_4,
+	IPC_MEM_PIPE_5,
+	IPC_MEM_PIPE_6,
+	IPC_MEM_PIPE_7,
+	IPC_MEM_PIPE_8,
+	IPC_MEM_PIPE_9,
+	IPC_MEM_PIPE_10,
+	IPC_MEM_PIPE_11,
+	IPC_MEM_PIPE_12,
+	IPC_MEM_PIPE_13,
+	IPC_MEM_PIPE_14,
+	IPC_MEM_PIPE_15,
+	IPC_MEM_PIPE_16,
+	IPC_MEM_PIPE_17,
+	IPC_MEM_PIPE_18,
+	IPC_MEM_PIPE_19,
+	IPC_MEM_PIPE_20,
+	IPC_MEM_PIPE_21,
+	IPC_MEM_PIPE_22,
+	IPC_MEM_PIPE_23,
+	IPC_MEM_MAX_PIPES
+};
+
+/* Enum defining channel states. */
+enum ipc_channel_state {
+	IMEM_CHANNEL_FREE,
+	IMEM_CHANNEL_RESERVED,
+	IMEM_CHANNEL_ACTIVE,
+	IMEM_CHANNEL_CLOSING,
+};
+
+/* Time Unit */
+enum ipc_time_unit {
+	IPC_SEC = 0,
+	IPC_MILLI_SEC = 1,
+	IPC_MICRO_SEC = 2,
+	IPC_NANO_SEC = 3,
+	IPC_PICO_SEC = 4,
+	IPC_FEMTO_SEC = 5,
+	IPC_ATTO_SEC = 6,
+};
+
+/**
+ * enum ipc_ctype - Enum defining supported channel type needed for control
+ *		    /IP traffic.
+ * @IPC_CTYPE_WWAN:		Used for IP traffic
+ * @IPC_CTYPE_CTRL:		Used for Control Communication
+ */
+enum ipc_ctype {
+	IPC_CTYPE_WWAN,
+	IPC_CTYPE_CTRL,
+};
+
+/* Pipe direction. */
+enum ipc_mem_pipe_dir {
+	IPC_MEM_DIR_UL,
+	IPC_MEM_DIR_DL,
+};
+
+/* HP update identifier. To be used as data for ipc_cp_irq_hpda_update() */
+enum ipc_hp_identifier {
+	IPC_HP_MR = 0,
+	IPC_HP_PM_TRIGGER,
+	IPC_HP_WAKEUP_SPEC_TMR,
+	IPC_HP_TD_UPD_TMR_START,
+	IPC_HP_TD_UPD_TMR,
+	IPC_HP_FAST_TD_UPD_TMR,
+	IPC_HP_UL_WRITE_TD,
+	IPC_HP_DL_PROCESS,
+	IPC_HP_NET_CHANNEL_INIT,
+	IPC_HP_CDEV_OPEN,
+};
+
+/**
+ * struct ipc_pipe - Structure for Pipe.
+ * @tdr_start:			Ipc private protocol Transfer Descriptor Ring
+ * @channel:			Id of the sio device, set by imem_sio_open,
+ *				needed to pass DL char to the user terminal
+ * @skbr_start:			Circular buffer for skbuf and the buffer
+ *				reference in a tdr_start entry.
+ * @phy_tdr_start:		Transfer descriptor start address
+ * @old_head:			last head pointer reported to CP.
+ * @old_tail:			AP read position before CP moves the read
+ *				position to write/head. If CP has consumed the
+ *				buffers, AP has to freed the skbuf starting at
+ *				tdr_start[old_tail].
+ * @nr_of_entries:		Number of elements of skb_start and tdr_start.
+ * @max_nr_of_queued_entries:	Maximum number of queued entries in TDR
+ * @accumulation_backoff:	Accumulation in usec for accumulation
+ *				backoff (0 = no acc backoff)
+ * @irq_moderation:		timer in usec for irq_moderation
+ *				(0=no irq moderation)
+ * @pipe_nr:			Pipe identification number
+ * @irq:			Interrupt vector
+ * @dir:			Direction of data stream in pipe
+ * @td_tag:			Unique tag of the buffer queued
+ * @buf_size:			Buffer size (in bytes) for preallocated
+ *				buffers (for DL pipes)
+ * @nr_of_queued_entries:	Aueued number of entries
+ * @is_open:			Check for open pipe status
+ */
+struct ipc_pipe {
+	struct ipc_protocol_td *tdr_start;
+	struct ipc_mem_channel *channel;
+	struct sk_buff **skbr_start;
+	dma_addr_t phy_tdr_start;
+	u32 old_head;
+	u32 old_tail;
+	u32 nr_of_entries;
+	u32 max_nr_of_queued_entries;
+	u32 accumulation_backoff;
+	u32 irq_moderation;
+	u32 pipe_nr;
+	u32 irq;
+	enum ipc_mem_pipe_dir dir;
+	u32 td_tag;
+	u32 buf_size;
+	u16 nr_of_queued_entries;
+	u8 is_open:1;
+};
+
+/**
+ * struct ipc_mem_channel - Structure for Channel.
+ * @channel_id:		Instance of the channel list and is return to the user
+ *			at the end of the open operation.
+ * @ctype:		Control or netif channel.
+ * @index:		unique index per ctype
+ * @ul_pipe:		pipe objects
+ * @dl_pipe:		pipe objects
+ * @if_id:		Interface ID
+ * @net_err_count:	Number of downlink errors returned by ipc_wwan_receive
+ *			interface at the entry point of the IP stack.
+ * @state:		Free, reserved or busy (in use).
+ * @ul_sem:		Needed for the blocking write or uplink transfer.
+ * @ul_list:		Uplink accumulator which is filled by the uplink
+ *			char app or IP stack. The socket buffer pointer are
+ *			added to the descriptor list in the kthread context.
+ */
+struct ipc_mem_channel {
+	int channel_id;
+	enum ipc_ctype ctype;
+	int index;
+	struct ipc_pipe ul_pipe;
+	struct ipc_pipe dl_pipe;
+	int if_id;
+	u32 net_err_count;
+	enum ipc_channel_state state;
+	struct completion ul_sem;
+	struct sk_buff_head ul_list;
+};
+
+/**
+ * enum ipc_phase - Different AP and CP phases.
+ *		    The enums defined after "IPC_P_ROM" and before
+ *		    "IPC_P_RUN" indicates the operating state where CP can
+ *		    respond to any requests. So while introducing new phase
+ *		    this shall be taken into consideration.
+ * @IPC_P_OFF:		On host PC, the PCIe device link settings are known
+ *			about the combined power on. PC is running, the driver
+ *			is loaded and CP is in power off mode. The PCIe bus
+ *			driver call the device power mode D3hot. In this phase
+ *			the driver the polls the device, until the device is in
+ *			the power on state and signals the power mode D0.
+ * @IPC_P_OFF_REQ:	The intermediate phase between cleanup activity starts
+ *			and ends.
+ * @IPC_P_CRASH:	The phase indicating CP crash
+ * @IPC_P_CD_READY:	The phase indicating CP core dump is ready
+ * @IPC_P_ROM:		After power on, CP starts in ROM mode and the IPC ROM
+ *			driver is waiting 150 ms for the AP active notification
+ *			saved in the PCI link status register.
+ * @IPC_P_PSI:		Primary signed image download phase
+ * @IPC_P_EBL:		Extended bootloader pahse
+ * @IPC_P_RUN:		The phase after flashing to RAM is the RUNTIME phase.
+ */
+enum ipc_phase {
+	IPC_P_OFF,
+	IPC_P_OFF_REQ,
+	IPC_P_CRASH,
+	IPC_P_CD_READY,
+	IPC_P_ROM,
+	IPC_P_PSI,
+	IPC_P_EBL,
+	IPC_P_RUN,
+};
+
+/**
+ * struct iosm_imem - Current state of the IPC shared memory.
+ * @mmio:			mmio instance to access CP MMIO area /
+ *				doorbell scratchpad.
+ * @ipc_protocol:		IPC Protocol instance
+ * @ipc_task:			Task for entry into ipc task queue
+ * @wwan:			WWAN device pointer
+ * @mux:			IP Data multiplexing state.
+ * @sio:			IPC SIO data structure pointer
+ * @ipc_port:			IPC PORT data structure pointer
+ * @pcie:			IPC PCIe
+ * @dev:			Pointer to device structure
+ * @flash_channel_id:		Reserved channel id for flashing to RAM.
+ * @ipc_requested_state:	Expected IPC state on CP.
+ * @channels:			Channel list with UL/DL pipe pairs.
+ * @ipc_status:			local ipc_status
+ * @nr_of_channels:		number of configured channels
+ * @startup_timer:		startup timer for NAND support.
+ * @hrtimer_period:		Hr timer period
+ * @tdupdate_timer:		Delay the TD update doorbell.
+ * @fast_update_timer:		forced head pointer update delay timer.
+ * @td_alloc_timer:		Timer for DL pipe TD allocation retry
+ * @rom_exit_code:		Mapped boot rom exit code.
+ * @enter_runtime:		1 means the transition to runtime phase was
+ *				executed.
+ * @ul_pend_sem:		Semaphore to wait/complete of UL TDs
+ *				before closing pipe.
+ * @app_notify_ul_pend:		Signal app if UL TD is pending
+ * @dl_pend_sem:		Semaphore to wait/complete of DL TDs
+ *				before closing pipe.
+ * @app_notify_dl_pend:		Signal app if DL TD is pending
+ * @phase:			Operating phase like runtime.
+ * @pci_device_id:		Device ID
+ * @cp_version:			CP version
+ * @device_sleep:		Device sleep state
+ * @run_state_worker:		Pointer to worker component for device
+ *				setup operations to be called when modem
+ *				reaches RUN state
+ * @ev_irq_pending:		0 means inform the IPC tasklet to
+ *				process the irq actions.
+ * @flag:			Flag to monitor the state of driver
+ * @td_update_timer_suspended:	if true then td update timer suspend
+ * @ev_cdev_write_pending:	0 means inform the IPC tasklet to pass
+ *				the accumulated uplink buffers to CP.
+ * @ev_mux_net_transmit_pending:0 means inform the IPC tasklet to pass
+ * @reset_det_n:		Reset detect flag
+ * @pcie_wake_n:		Pcie wake flag
+ */
+struct iosm_imem {
+	struct iosm_mmio *mmio;
+	struct iosm_protocol *ipc_protocol;
+	struct ipc_task *ipc_task;
+	struct iosm_wwan *wwan;
+	struct iosm_mux *mux;
+	struct iosm_cdev *ipc_port[IPC_MEM_MAX_CHANNELS];
+	struct iosm_pcie *pcie;
+	struct device *dev;
+	int flash_channel_id;
+	enum ipc_mem_device_ipc_state ipc_requested_state;
+	struct ipc_mem_channel channels[IPC_MEM_MAX_CHANNELS];
+	u32 ipc_status;
+	u32 nr_of_channels;
+	struct hrtimer startup_timer;
+	ktime_t hrtimer_period;
+	struct hrtimer tdupdate_timer;
+	struct hrtimer fast_update_timer;
+	struct hrtimer td_alloc_timer;
+	enum rom_exit_code rom_exit_code;
+	u32 enter_runtime;
+	struct completion ul_pend_sem;
+	u32 app_notify_ul_pend;
+	struct completion dl_pend_sem;
+	u32 app_notify_dl_pend;
+	enum ipc_phase phase;
+	u16 pci_device_id;
+	int cp_version;
+	int device_sleep;
+	struct work_struct run_state_worker;
+	u8 ev_irq_pending[IPC_IRQ_VECTORS];
+	unsigned long flag;
+	u8 td_update_timer_suspended:1,
+	   ev_cdev_write_pending:1,
+	   ev_mux_net_transmit_pending:1,
+	   reset_det_n:1,
+	   pcie_wake_n:1;
+};
+
+/**
+ * ipc_imem_init - Initialize the shared memory region
+ * @pcie:	Pointer to core driver data-struct
+ * @device_id:	PCI device ID
+ * @mmio:	Pointer to the mmio area
+ * @dev:	Pointer to device structure
+ *
+ * Returns:  Initialized imem pointer on success else NULL
+ */
+struct iosm_imem *ipc_imem_init(struct iosm_pcie *pcie, unsigned int device_id,
+				void __iomem *mmio, struct device *dev);
+
+/**
+ * ipc_imem_pm_s2idle_sleep - Set PM variables to sleep/active for
+ *			      s2idle sleep/active
+ * @ipc_imem:	Pointer to imem data-struct
+ * @sleep:	Set PM Variable to sleep/active
+ */
+void ipc_imem_pm_s2idle_sleep(struct iosm_imem *ipc_imem, bool sleep);
+
+/**
+ * ipc_imem_pm_suspend - The HAL shall ask the shared memory layer
+ *			 whether D3 is allowed.
+ * @ipc_imem:	Pointer to imem data-struct
+ */
+void ipc_imem_pm_suspend(struct iosm_imem *ipc_imem);
+
+/**
+ * ipc_imem_pm_resume - The HAL shall inform the shared memory layer
+ *			that the device is active.
+ * @ipc_imem:	Pointer to imem data-struct
+ */
+void ipc_imem_pm_resume(struct iosm_imem *ipc_imem);
+
+/**
+ * ipc_imem_cleanup -	Inform CP and free the shared memory resources.
+ * @ipc_imem:	Pointer to imem data-struct
+ */
+void ipc_imem_cleanup(struct iosm_imem *ipc_imem);
+
+/**
+ * ipc_imem_irq_process - Shift the IRQ actions to the IPC thread.
+ * @ipc_imem:	Pointer to imem data-struct
+ * @irq:	Irq number
+ */
+void ipc_imem_irq_process(struct iosm_imem *ipc_imem, int irq);
+
+/**
+ * imem_get_device_sleep_state - Get the device sleep state value.
+ * @ipc_imem:	Pointer to imem instance
+ *
+ * Returns: device sleep state
+ */
+int imem_get_device_sleep_state(struct iosm_imem *ipc_imem);
+
+/**
+ * ipc_imem_td_update_timer_suspend - Updates the TD Update Timer suspend flag.
+ * @ipc_imem:	Pointer to imem data-struct
+ * @suspend:	Flag to update. If TRUE then HP update doorbell is triggered to
+ *		device without any wait. If FALSE then HP update doorbell is
+ *		delayed until timeout.
+ */
+void ipc_imem_td_update_timer_suspend(struct iosm_imem *ipc_imem, bool suspend);
+
+/**
+ * ipc_imem_channel_close - Release the channel resources.
+ * @ipc_imem:		Pointer to imem data-struct
+ * @channel_id:		Channel ID to be cleaned up.
+ */
+void ipc_imem_channel_close(struct iosm_imem *ipc_imem, int channel_id);
+
+/**
+ * ipc_imem_channel_alloc - Reserves a channel
+ * @ipc_imem:	Pointer to imem data-struct
+ * @index:	ID to lookup from the preallocated list.
+ * @ctype:	Channel type.
+ *
+ * Returns: Index on success and failure value on error
+ */
+int ipc_imem_channel_alloc(struct iosm_imem *ipc_imem, int index,
+			   enum ipc_ctype ctype);
+
+/**
+ * ipc_imem_channel_open - Establish the pipes.
+ * @ipc_imem:		Pointer to imem data-struct
+ * @channel_id:		Channel ID returned during alloc.
+ * @db_id:		Doorbell ID for trigger identifier.
+ *
+ * Returns: Pointer of ipc_mem_channel on success and NULL on failure.
+ */
+struct ipc_mem_channel *ipc_imem_channel_open(struct iosm_imem *ipc_imem,
+					      int channel_id, u32 db_id);
+
+/**
+ * ipc_imem_td_update_timer_start - Starts the TD Update Timer if not running.
+ * @ipc_imem:	Pointer to imem data-struct
+ */
+void ipc_imem_td_update_timer_start(struct iosm_imem *ipc_imem);
+
+/**
+ * ipc_imem_ul_write_td - Pass the channel UL list to protocol layer for TD
+ *		      preparation and sending them to the device.
+ * @ipc_imem:	Pointer to imem data-struct
+ *
+ * Returns: TRUE of HP Doorbell trigger is pending. FALSE otherwise.
+ */
+bool ipc_imem_ul_write_td(struct iosm_imem *ipc_imem);
+
+/**
+ * ipc_imem_ul_send - Dequeue SKB from channel list and start with
+ *		  the uplink transfer.If HP Doorbell is pending to be
+ *		  triggered then starts the TD Update Timer.
+ * @ipc_imem:	Pointer to imem data-struct
+ */
+void ipc_imem_ul_send(struct iosm_imem *ipc_imem);
+
+/**
+ * ipc_imem_channel_update - Set or modify pipe config of an existing channel
+ * @ipc_imem:		Pointer to imem data-struct
+ * @id:			Channel config index
+ * @chnl_cfg:		Channel config struct
+ * @irq_moderation:	Timer in usec for irq_moderation
+ */
+void ipc_imem_channel_update(struct iosm_imem *ipc_imem, int id,
+			     struct ipc_chnl_cfg chnl_cfg, u32 irq_moderation);
+
+/**
+ * ipc_imem_channel_free -Free an IPC channel.
+ * @channel:	Channel to be freed
+ */
+void ipc_imem_channel_free(struct ipc_mem_channel *channel);
+
+/**
+ * ipc_imem_hrtimer_stop - Stop the hrtimer
+ * @hr_timer:	Pointer to hrtimer instance
+ */
+void ipc_imem_hrtimer_stop(struct hrtimer *hr_timer);
+
+/**
+ * ipc_imem_pipe_cleanup - Reset volatile pipe content for all channels
+ * @ipc_imem:	Pointer to imem data-struct
+ * @pipe:	Pipe to cleaned up
+ */
+void ipc_imem_pipe_cleanup(struct iosm_imem *ipc_imem, struct ipc_pipe *pipe);
+
+/**
+ * ipc_imem_pipe_close - Send msg to device to close pipe
+ * @ipc_imem:	Pointer to imem data-struct
+ * @pipe:	Pipe to be closed
+ */
+void ipc_imem_pipe_close(struct iosm_imem *ipc_imem, struct ipc_pipe *pipe);
+
+/**
+ * ipc_imem_phase_update - Get the CP execution state
+ *			  and map it to the AP phase.
+ * @ipc_imem:	Pointer to imem data-struct
+ *
+ * Returns: Current ap updated phase
+ */
+enum ipc_phase ipc_imem_phase_update(struct iosm_imem *ipc_imem);
+
+/**
+ * ipc_imem_phase_get_string - Return the current operation
+ *			     phase as string.
+ * @phase:	AP phase
+ *
+ * Returns: AP phase string
+ */
+const char *ipc_imem_phase_get_string(enum ipc_phase phase);
+
+/**
+ * ipc_imem_msg_send_feature_set - Send feature set message to modem
+ * @ipc_imem:		Pointer to imem data-struct
+ * @reset_enable:	0 = out-of-band, 1 = in-band-crash notification
+ * @atomic_ctx:		if disabled call in tasklet context
+ *
+ */
+void ipc_imem_msg_send_feature_set(struct iosm_imem *ipc_imem,
+				   unsigned int reset_enable, bool atomic_ctx);
+
+/**
+ * ipc_imem_ipc_init_check - Send the init event to CP, wait a certain time and
+ *			     set CP to runtime with the context information
+ * @ipc_imem:	Pointer to imem data-struct
+ */
+void ipc_imem_ipc_init_check(struct iosm_imem *ipc_imem);
+
+/**
+ * ipc_imem_channel_init - Initialize the channel list with UL/DL pipe pairs.
+ * @ipc_imem:		Pointer to imem data-struct
+ * @ctype:		Channel type
+ * @chnl_cfg:		Channel configuration struct
+ * @irq_moderation:	Timer in usec for irq_moderation
+ */
+void ipc_imem_channel_init(struct iosm_imem *ipc_imem, enum ipc_ctype ctype,
+			   struct ipc_chnl_cfg chnl_cfg, u32 irq_moderation);
+#endif