/*
 * Copyright 2016-17 IBM Corp.
 *
 * 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; either version
 * 2 of the License, or (at your option) any later version.
 */

#ifndef _VAS_H
#define _VAS_H
#include <linux/atomic.h>
#include <linux/idr.h>
#include <asm/vas.h>
#include <linux/io.h>
#include <linux/dcache.h>
#include <linux/mutex.h>

/*
 * Overview of Virtual Accelerator Switchboard (VAS).
 *
 * VAS is a hardware "switchboard" that allows senders and receivers to
 * exchange messages with _minimal_ kernel involvment. The receivers are
 * typically NX coprocessor engines that perform compression or encryption
 * in hardware, but receivers can also be other software threads.
 *
 * Senders are user/kernel threads that submit compression/encryption or
 * other requests to the receivers. Senders must format their messages as
 * Coprocessor Request Blocks (CRB)s and submit them using the "copy" and
 * "paste" instructions which were introduced in Power9.
 *
 * A Power node can have (upto?) 8 Power chips. There is one instance of
 * VAS in each Power9 chip. Each instance of VAS has 64K windows or ports,
 * Senders and receivers must each connect to a separate window before they
 * can exchange messages through the switchboard.
 *
 * Each window is described by two types of window contexts:
 *
 *      Hypervisor Window Context (HVWC) of size VAS_HVWC_SIZE bytes
 *
 *      OS/User Window Context (UWC) of size VAS_UWC_SIZE bytes.
 *
 * A window context can be viewed as a set of 64-bit registers. The settings
 * in these registers configure/control/determine the behavior of the VAS
 * hardware when messages are sent/received through the window. The registers
 * in the HVWC are configured by the kernel while the registers in the UWC can
 * be configured by the kernel or by the user space application that is using
 * the window.
 *
 * The HVWCs for all windows on a specific instance of VAS are in a contiguous
 * range of hardware addresses or Base address region (BAR) referred to as the
 * HVWC BAR for the instance. Similarly the UWCs for all windows on an instance
 * are referred to as the UWC BAR for the instance.
 *
 * The two BARs for each instance are defined Power9 MMIO Ranges spreadsheet
 * and available to the kernel in the VAS node's "reg" property in the device
 * tree:
 *
 *      /proc/device-tree/vasm@.../reg
 *
 * (see vas_probe() for details on the reg property).
 *
 * The kernel maps the HVWC and UWC BAR regions into the kernel address
 * space (hvwc_map and uwc_map). The kernel can then access the window
 * contexts of a specific window using:
 *
 *       hvwc = hvwc_map + winid * VAS_HVWC_SIZE.
 *       uwc = uwc_map + winid * VAS_UWC_SIZE.
 *
 * where winid is the window index (0..64K).
 *
 * As mentioned, a window context is used to "configure" a window. Besides
 * this configuration address, each _send_ window also has a unique hardware
 * "paste" address that is used to submit requests/CRBs (see vas_paste_crb()).
 *
 * The hardware paste address for a window is computed using the "paste
 * base address" and "paste win id shift" reg properties in the VAS device
 * tree node using:
 *
 *      paste_addr = paste_base + ((winid << paste_win_id_shift))
 *
 * (again, see vas_probe() for ->paste_base_addr and ->paste_win_id_shift).
 *
 * The kernel maps this hardware address into the sender's address space
 * after which they can use the 'paste' instruction (new in Power9) to
 * send a message (submit a request aka CRB) to the coprocessor.
 *
 * NOTE: In the initial version, senders can only in-kernel drivers/threads.
 *       Support for user space threads will be added in follow-on patches.
 *
 * TODO: Do we need to map the UWC into user address space so they can return
 *       credits? Its NA for NX but may be needed for other receive windows.
 *
 */

#define VAS_WINDOWS_PER_CHIP            (64 << 10)

/*
 * Hypervisor and OS/USer Window Context sizes
 */
#define VAS_HVWC_SIZE                   512
#define VAS_UWC_SIZE                    PAGE_SIZE

/*
 * Initial per-process credits.
 * Max send window credits:    4K-1 (12-bits in VAS_TX_WCRED)
 * Max receive window credits: 64K-1 (16 bits in VAS_LRX_WCRED)
 *
 * TODO: Needs tuning for per-process credits
 */
#define VAS_RX_WCREDS_MAX               ((64 << 10) - 1)
#define VAS_TX_WCREDS_MAX               ((4 << 10) - 1)
#define VAS_WCREDS_DEFAULT              (1 << 10)

/*
 * VAS Window Context Register Offsets and bitmasks.
 * See Section 3.1.4 of VAS Work book
 */
#define VAS_LPID_OFFSET                 0x010
#define VAS_LPID                        PPC_BITMASK(0, 11)

#define VAS_PID_OFFSET                  0x018
#define VAS_PID_ID                      PPC_BITMASK(0, 19)

#define VAS_XLATE_MSR_OFFSET            0x020
#define VAS_XLATE_MSR_DR                PPC_BIT(0)
#define VAS_XLATE_MSR_TA                PPC_BIT(1)
#define VAS_XLATE_MSR_PR                PPC_BIT(2)
#define VAS_XLATE_MSR_US                PPC_BIT(3)
#define VAS_XLATE_MSR_HV                PPC_BIT(4)
#define VAS_XLATE_MSR_SF                PPC_BIT(5)

#define VAS_XLATE_LPCR_OFFSET           0x028
#define VAS_XLATE_LPCR_PAGE_SIZE        PPC_BITMASK(0, 2)
#define VAS_XLATE_LPCR_ISL              PPC_BIT(3)
#define VAS_XLATE_LPCR_TC               PPC_BIT(4)
#define VAS_XLATE_LPCR_SC               PPC_BIT(5)

#define VAS_XLATE_CTL_OFFSET            0x030
#define VAS_XLATE_MODE                  PPC_BITMASK(0, 1)

#define VAS_AMR_OFFSET                  0x040
#define VAS_AMR                         PPC_BITMASK(0, 63)

#define VAS_SEIDR_OFFSET                0x048
#define VAS_SEIDR                       PPC_BITMASK(0, 63)

#define VAS_FAULT_TX_WIN_OFFSET         0x050
#define VAS_FAULT_TX_WIN                PPC_BITMASK(48, 63)

#define VAS_OSU_INTR_SRC_RA_OFFSET      0x060
#define VAS_OSU_INTR_SRC_RA             PPC_BITMASK(8, 63)

#define VAS_HV_INTR_SRC_RA_OFFSET       0x070
#define VAS_HV_INTR_SRC_RA              PPC_BITMASK(8, 63)

#define VAS_PSWID_OFFSET                0x078
#define VAS_PSWID_EA_HANDLE             PPC_BITMASK(0, 31)

#define VAS_SPARE1_OFFSET               0x080
#define VAS_SPARE2_OFFSET               0x088
#define VAS_SPARE3_OFFSET               0x090
#define VAS_SPARE4_OFFSET               0x130
#define VAS_SPARE5_OFFSET               0x160
#define VAS_SPARE6_OFFSET               0x188

#define VAS_LFIFO_BAR_OFFSET            0x0A0
#define VAS_LFIFO_BAR                   PPC_BITMASK(8, 53)
#define VAS_PAGE_MIGRATION_SELECT       PPC_BITMASK(54, 56)

#define VAS_LDATA_STAMP_CTL_OFFSET      0x0A8
#define VAS_LDATA_STAMP                 PPC_BITMASK(0, 1)
#define VAS_XTRA_WRITE                  PPC_BIT(2)

#define VAS_LDMA_CACHE_CTL_OFFSET       0x0B0
#define VAS_LDMA_TYPE                   PPC_BITMASK(0, 1)
#define VAS_LDMA_FIFO_DISABLE           PPC_BIT(2)

#define VAS_LRFIFO_PUSH_OFFSET          0x0B8
#define VAS_LRFIFO_PUSH                 PPC_BITMASK(0, 15)

#define VAS_CURR_MSG_COUNT_OFFSET       0x0C0
#define VAS_CURR_MSG_COUNT              PPC_BITMASK(0, 7)

#define VAS_LNOTIFY_AFTER_COUNT_OFFSET  0x0C8
#define VAS_LNOTIFY_AFTER_COUNT         PPC_BITMASK(0, 7)

#define VAS_LRX_WCRED_OFFSET            0x0E0
#define VAS_LRX_WCRED                   PPC_BITMASK(0, 15)

#define VAS_LRX_WCRED_ADDER_OFFSET      0x190
#define VAS_LRX_WCRED_ADDER             PPC_BITMASK(0, 15)

#define VAS_TX_WCRED_OFFSET             0x0F0
#define VAS_TX_WCRED                    PPC_BITMASK(4, 15)

#define VAS_TX_WCRED_ADDER_OFFSET       0x1A0
#define VAS_TX_WCRED_ADDER              PPC_BITMASK(4, 15)

#define VAS_LFIFO_SIZE_OFFSET           0x100
#define VAS_LFIFO_SIZE                  PPC_BITMASK(0, 3)

#define VAS_WINCTL_OFFSET               0x108
#define VAS_WINCTL_OPEN                 PPC_BIT(0)
#define VAS_WINCTL_REJ_NO_CREDIT        PPC_BIT(1)
#define VAS_WINCTL_PIN                  PPC_BIT(2)
#define VAS_WINCTL_TX_WCRED_MODE        PPC_BIT(3)
#define VAS_WINCTL_RX_WCRED_MODE        PPC_BIT(4)
#define VAS_WINCTL_TX_WORD_MODE         PPC_BIT(5)
#define VAS_WINCTL_RX_WORD_MODE         PPC_BIT(6)
#define VAS_WINCTL_RSVD_TXBUF           PPC_BIT(7)
#define VAS_WINCTL_THRESH_CTL           PPC_BITMASK(8, 9)
#define VAS_WINCTL_FAULT_WIN            PPC_BIT(10)
#define VAS_WINCTL_NX_WIN               PPC_BIT(11)

#define VAS_WIN_STATUS_OFFSET           0x110
#define VAS_WIN_BUSY                    PPC_BIT(1)

#define VAS_WIN_CTX_CACHING_CTL_OFFSET  0x118
#define VAS_CASTOUT_REQ                 PPC_BIT(0)
#define VAS_PUSH_TO_MEM                 PPC_BIT(1)
#define VAS_WIN_CACHE_STATUS            PPC_BIT(4)

#define VAS_TX_RSVD_BUF_COUNT_OFFSET    0x120
#define VAS_RXVD_BUF_COUNT              PPC_BITMASK(58, 63)

#define VAS_LRFIFO_WIN_PTR_OFFSET       0x128
#define VAS_LRX_WIN_ID                  PPC_BITMASK(0, 15)

/*
 * Local Notification Control Register controls what happens in _response_
 * to a paste command and hence applies only to receive windows.
 */
#define VAS_LNOTIFY_CTL_OFFSET          0x138
#define VAS_NOTIFY_DISABLE              PPC_BIT(0)
#define VAS_INTR_DISABLE                PPC_BIT(1)
#define VAS_NOTIFY_EARLY                PPC_BIT(2)
#define VAS_NOTIFY_OSU_INTR             PPC_BIT(3)

#define VAS_LNOTIFY_PID_OFFSET          0x140
#define VAS_LNOTIFY_PID                 PPC_BITMASK(0, 19)

#define VAS_LNOTIFY_LPID_OFFSET         0x148
#define VAS_LNOTIFY_LPID                PPC_BITMASK(0, 11)

#define VAS_LNOTIFY_TID_OFFSET          0x150
#define VAS_LNOTIFY_TID                 PPC_BITMASK(0, 15)

#define VAS_LNOTIFY_SCOPE_OFFSET        0x158
#define VAS_LNOTIFY_MIN_SCOPE           PPC_BITMASK(0, 1)
#define VAS_LNOTIFY_MAX_SCOPE           PPC_BITMASK(2, 3)

#define VAS_NX_UTIL_OFFSET              0x1B0
#define VAS_NX_UTIL                     PPC_BITMASK(0, 63)

/* SE: Side effects */
#define VAS_NX_UTIL_SE_OFFSET           0x1B8
#define VAS_NX_UTIL_SE                  PPC_BITMASK(0, 63)

#define VAS_NX_UTIL_ADDER_OFFSET        0x180
#define VAS_NX_UTIL_ADDER               PPC_BITMASK(32, 63)

/*
 * VREG(x):
 * Expand a register's short name (eg: LPID) into two parameters:
 *      - the register's short name in string form ("LPID"), and
 *      - the name of the macro (eg: VAS_LPID_OFFSET), defining the
 *        register's offset in the window context
 */
#define VREG_SFX(n, s)  __stringify(n), VAS_##n##s
#define VREG(r)         VREG_SFX(r, _OFFSET)

/*
 * Local Notify Scope Control Register. (Receive windows only).
 */
enum vas_notify_scope {
        VAS_SCOPE_LOCAL,
        VAS_SCOPE_GROUP,
        VAS_SCOPE_VECTORED_GROUP,
        VAS_SCOPE_UNUSED,
};

/*
 * Local DMA Cache Control Register (Receive windows only).
 */
enum vas_dma_type {
        VAS_DMA_TYPE_INJECT,
        VAS_DMA_TYPE_WRITE,
};

/*
 * Local Notify Scope Control Register. (Receive windows only).
 * Not applicable to NX receive windows.
 */
enum vas_notify_after_count {
        VAS_NOTIFY_AFTER_256 = 0,
        VAS_NOTIFY_NONE,
        VAS_NOTIFY_AFTER_2
};

/*
 * One per instance of VAS. Each instance will have a separate set of
 * receive windows, one per coprocessor type.
 *
 * See also function header of set_vinst_win() for details on ->windows[]
 * and ->rxwin[] tables.
 */
struct vas_instance {
        int vas_id;
        struct ida ida;
        struct list_head node;
        struct platform_device *pdev;

        u64 hvwc_bar_start;
        u64 uwc_bar_start;
        u64 paste_base_addr;
        u64 paste_win_id_shift;

        struct mutex mutex;
        struct vas_window *rxwin[VAS_COP_TYPE_MAX];
        struct vas_window *windows[VAS_WINDOWS_PER_CHIP];

        char *dbgname;
        struct dentry *dbgdir;
};

/*
 * In-kernel state a VAS window. One per window.
 */
struct vas_window {
        /* Fields common to send and receive windows */
        struct vas_instance *vinst;
        int winid;
        bool tx_win;            /* True if send window */
        bool nx_win;            /* True if NX window */
        bool user_win;          /* True if user space window */
        void *hvwc_map;         /* HV window context */
        void *uwc_map;          /* OS/User window context */
        pid_t pid;              /* Linux process id of owner */
        int wcreds_max;         /* Window credits */

        char *dbgname;
        struct dentry *dbgdir;

        /* Fields applicable only to send windows */
        void *paste_kaddr;
        char *paste_addr_name;
        struct vas_window *rxwin;

        /* Feilds applicable only to receive windows */
        enum vas_cop_type cop;
        atomic_t num_txwins;
};

/*
 * Container for the hardware state of a window. One per-window.
 *
 * A VAS Window context is a 512-byte area in the hardware that contains
 * a set of 64-bit registers. Individual bit-fields in these registers
 * determine the configuration/operation of the hardware. struct vas_winctx
 * is a container for the register fields in the window context.
 */
struct vas_winctx {
        void *rx_fifo;
        int rx_fifo_size;
        int wcreds_max;
        int rsvd_txbuf_count;

        bool user_win;
        bool nx_win;
        bool fault_win;
        bool rsvd_txbuf_enable;
        bool pin_win;
        bool rej_no_credit;
        bool tx_wcred_mode;
        bool rx_wcred_mode;
        bool tx_word_mode;
        bool rx_word_mode;
        bool data_stamp;
        bool xtra_write;
        bool notify_disable;
        bool intr_disable;
        bool fifo_disable;
        bool notify_early;
        bool notify_os_intr_reg;

        int lpid;
        int pidr;               /* value from SPRN_PID, not linux pid */
        int lnotify_lpid;
        int lnotify_pid;
        int lnotify_tid;
        u32 pswid;
        int rx_win_id;
        int fault_win_id;
        int tc_mode;

        u64 irq_port;

        enum vas_dma_type dma_type;
        enum vas_notify_scope min_scope;
        enum vas_notify_scope max_scope;
        enum vas_notify_after_count notify_after_count;
};

extern struct mutex vas_mutex;

extern struct vas_instance *find_vas_instance(int vasid);
extern void vas_init_dbgdir(void);
extern void vas_instance_init_dbgdir(struct vas_instance *vinst);
extern void vas_window_init_dbgdir(struct vas_window *win);
extern void vas_window_free_dbgdir(struct vas_window *win);

static inline void vas_log_write(struct vas_window *win, char *name,
                        void *regptr, u64 val)
{
        if (val)
                pr_debug("%swin #%d: %s reg %p, val 0x%016llx\n",
                                win->tx_win ? "Tx" : "Rx", win->winid, name,
                                regptr, val);
}

static inline void write_uwc_reg(struct vas_window *win, char *name,
                        s32 reg, u64 val)
{
        void *regptr;

        regptr = win->uwc_map + reg;
        vas_log_write(win, name, regptr, val);

        out_be64(regptr, val);
}

static inline void write_hvwc_reg(struct vas_window *win, char *name,
                        s32 reg, u64 val)
{
        void *regptr;

        regptr = win->hvwc_map + reg;
        vas_log_write(win, name, regptr, val);

        out_be64(regptr, val);
}

static inline u64 read_hvwc_reg(struct vas_window *win,
                        char *name __maybe_unused, s32 reg)
{
        return in_be64(win->hvwc_map+reg);
}

/*
 * Encode/decode the Partition Send Window ID (PSWID) for a window in
 * a way that we can uniquely identify any window in the system. i.e.
 * we should be able to locate the 'struct vas_window' given the PSWID.
 *
 *      Bits    Usage
 *      0:7     VAS id (8 bits)
 *      8:15    Unused, 0 (3 bits)
 *      16:31   Window id (16 bits)
 */
static inline u32 encode_pswid(int vasid, int winid)
{
        u32 pswid = 0;

        pswid |= vasid << (31 - 7);
        pswid |= winid;

        return pswid;
}

static inline void decode_pswid(u32 pswid, int *vasid, int *winid)
{
        if (vasid)
                *vasid = pswid >> (31 - 7) & 0xFF;

        if (winid)
                *winid = pswid & 0xFFFF;
}
#endif /* _VAS_H */