diff options
Diffstat (limited to 'drivers/mailbox/arm_mhuv2.c')
| -rw-r--r-- | drivers/mailbox/arm_mhuv2.c | 1137 |
1 files changed, 1137 insertions, 0 deletions
diff --git a/drivers/mailbox/arm_mhuv2.c b/drivers/mailbox/arm_mhuv2.c new file mode 100644 index 000000000..c6d4957c4 --- /dev/null +++ b/drivers/mailbox/arm_mhuv2.c @@ -0,0 +1,1137 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * ARM Message Handling Unit Version 2 (MHUv2) driver. + * + * Copyright (C) 2020 ARM Ltd. + * Copyright (C) 2020 Linaro Ltd. + * + * An MHUv2 mailbox controller can provide up to 124 channel windows (each 32 + * bit long) and the driver allows any combination of both the transport + * protocol modes: data-transfer and doorbell, to be used on those channel + * windows. + * + * The transport protocols should be specified in the device tree entry for the + * device. The transport protocols determine how the underlying hardware + * resources of the device are utilized when transmitting data. Refer to the + * device tree bindings of the ARM MHUv2 controller for more details. + * + * The number of registered mailbox channels is dependent on both the underlying + * hardware - mainly the number of channel windows implemented by the platform, + * as well as the selected transport protocols. + * + * The MHUv2 controller can work both as a sender and receiver, but the driver + * and the DT bindings support unidirectional transfers for better allocation of + * the channels. That is, this driver will be probed for two separate devices + * for each mailbox controller, a sender device and a receiver device. + */ + +#include <linux/amba/bus.h> +#include <linux/interrupt.h> +#include <linux/mailbox_controller.h> +#include <linux/mailbox/arm_mhuv2_message.h> +#include <linux/module.h> +#include <linux/of_address.h> +#include <linux/spinlock.h> + +/* ====== MHUv2 Registers ====== */ + +/* Maximum number of channel windows */ +#define MHUV2_CH_WN_MAX 124 +/* Number of combined interrupt status registers */ +#define MHUV2_CMB_INT_ST_REG_CNT 4 +#define MHUV2_STAT_BYTES (sizeof(u32)) +#define MHUV2_STAT_BITS (MHUV2_STAT_BYTES * __CHAR_BIT__) + +#define LSB_MASK(n) ((1 << (n * __CHAR_BIT__)) - 1) +#define MHUV2_PROTOCOL_PROP "arm,mhuv2-protocols" + +/* Register Message Handling Unit Configuration fields */ +struct mhu_cfg_t { + u32 num_ch : 7; + u32 pad : 25; +} __packed; + +/* register Interrupt Status fields */ +struct int_st_t { + u32 nr2r : 1; + u32 r2nr : 1; + u32 pad : 30; +} __packed; + +/* Register Interrupt Clear fields */ +struct int_clr_t { + u32 nr2r : 1; + u32 r2nr : 1; + u32 pad : 30; +} __packed; + +/* Register Interrupt Enable fields */ +struct int_en_t { + u32 r2nr : 1; + u32 nr2r : 1; + u32 chcomb : 1; + u32 pad : 29; +} __packed; + +/* Register Implementer Identification fields */ +struct iidr_t { + u32 implementer : 12; + u32 revision : 4; + u32 variant : 4; + u32 product_id : 12; +} __packed; + +/* Register Architecture Identification Register fields */ +struct aidr_t { + u32 arch_minor_rev : 4; + u32 arch_major_rev : 4; + u32 pad : 24; +} __packed; + +/* Sender Channel Window fields */ +struct mhu2_send_ch_wn_reg { + u32 stat; + u8 pad1[0x0C - 0x04]; + u32 stat_set; + u32 int_st; + u32 int_clr; + u32 int_en; + u8 pad2[0x20 - 0x1C]; +} __packed; + +/* Sender frame register fields */ +struct mhu2_send_frame_reg { + struct mhu2_send_ch_wn_reg ch_wn[MHUV2_CH_WN_MAX]; + struct mhu_cfg_t mhu_cfg; + u32 resp_cfg; + u32 access_request; + u32 access_ready; + struct int_st_t int_st; + struct int_clr_t int_clr; + struct int_en_t int_en; + u32 reserved0; + u32 chcomb_int_st[MHUV2_CMB_INT_ST_REG_CNT]; + u8 pad[0xFC8 - 0xFB0]; + struct iidr_t iidr; + struct aidr_t aidr; +} __packed; + +/* Receiver Channel Window fields */ +struct mhu2_recv_ch_wn_reg { + u32 stat; + u32 stat_masked; + u32 stat_clear; + u8 reserved0[0x10 - 0x0C]; + u32 mask; + u32 mask_set; + u32 mask_clear; + u8 pad[0x20 - 0x1C]; +} __packed; + +/* Receiver frame register fields */ +struct mhu2_recv_frame_reg { + struct mhu2_recv_ch_wn_reg ch_wn[MHUV2_CH_WN_MAX]; + struct mhu_cfg_t mhu_cfg; + u8 reserved0[0xF90 - 0xF84]; + struct int_st_t int_st; + struct int_clr_t int_clr; + struct int_en_t int_en; + u32 pad; + u32 chcomb_int_st[MHUV2_CMB_INT_ST_REG_CNT]; + u8 reserved2[0xFC8 - 0xFB0]; + struct iidr_t iidr; + struct aidr_t aidr; +} __packed; + + +/* ====== MHUv2 data structures ====== */ + +enum mhuv2_transport_protocol { + DOORBELL = 0, + DATA_TRANSFER = 1 +}; + +enum mhuv2_frame { + RECEIVER_FRAME, + SENDER_FRAME +}; + +/** + * struct mhuv2 - MHUv2 mailbox controller data + * + * @mbox: Mailbox controller belonging to the MHU frame. + * @send: Base address of the register mapping region. + * @recv: Base address of the register mapping region. + * @frame: Frame type: RECEIVER_FRAME or SENDER_FRAME. + * @irq: Interrupt. + * @windows: Channel windows implemented by the platform. + * @minor: Minor version of the controller. + * @length: Length of the protocols array in bytes. + * @protocols: Raw protocol information, derived from device tree. + * @doorbell_pending_lock: spinlock required for correct operation of Tx + * interrupt for doorbells. + */ +struct mhuv2 { + struct mbox_controller mbox; + union { + struct mhu2_send_frame_reg __iomem *send; + struct mhu2_recv_frame_reg __iomem *recv; + }; + enum mhuv2_frame frame; + unsigned int irq; + unsigned int windows; + unsigned int minor; + unsigned int length; + u32 *protocols; + + spinlock_t doorbell_pending_lock; +}; + +#define mhu_from_mbox(_mbox) container_of(_mbox, struct mhuv2, mbox) + +/** + * struct mhuv2_protocol_ops - MHUv2 operations + * + * Each transport protocol must provide an implementation of the operations + * provided here. + * + * @rx_startup: Startup callback for receiver. + * @rx_shutdown: Shutdown callback for receiver. + * @read_data: Reads and clears newly available data. + * @tx_startup: Startup callback for receiver. + * @tx_shutdown: Shutdown callback for receiver. + * @last_tx_done: Report back if the last tx is completed or not. + * @send_data: Send data to the receiver. + */ +struct mhuv2_protocol_ops { + int (*rx_startup)(struct mhuv2 *mhu, struct mbox_chan *chan); + void (*rx_shutdown)(struct mhuv2 *mhu, struct mbox_chan *chan); + void *(*read_data)(struct mhuv2 *mhu, struct mbox_chan *chan); + + void (*tx_startup)(struct mhuv2 *mhu, struct mbox_chan *chan); + void (*tx_shutdown)(struct mhuv2 *mhu, struct mbox_chan *chan); + int (*last_tx_done)(struct mhuv2 *mhu, struct mbox_chan *chan); + int (*send_data)(struct mhuv2 *mhu, struct mbox_chan *chan, void *arg); +}; + +/* + * MHUv2 mailbox channel's private information + * + * @ops: protocol specific ops for the channel. + * @ch_wn_idx: Channel window index allocated to the channel. + * @windows: Total number of windows consumed by the channel, only relevant + * in DATA_TRANSFER protocol. + * @doorbell: Doorbell bit number within the ch_wn_idx window, only relevant + * in DOORBELL protocol. + * @pending: Flag indicating pending doorbell interrupt, only relevant in + * DOORBELL protocol. + */ +struct mhuv2_mbox_chan_priv { + const struct mhuv2_protocol_ops *ops; + u32 ch_wn_idx; + union { + u32 windows; + struct { + u32 doorbell; + u32 pending; + }; + }; +}; + +/* Macro for reading a bitfield within a physically mapped packed struct */ +#define readl_relaxed_bitfield(_regptr, _type, _field) \ + ({ \ + u32 _regval; \ + _regval = readl_relaxed((_regptr)); \ + (*(_type *)(&_regval))._field; \ + }) + +/* Macro for writing a bitfield within a physically mapped packed struct */ +#define writel_relaxed_bitfield(_value, _regptr, _type, _field) \ + ({ \ + u32 _regval; \ + _regval = readl_relaxed(_regptr); \ + (*(_type *)(&_regval))._field = _value; \ + writel_relaxed(_regval, _regptr); \ + }) + + +/* =================== Doorbell transport protocol operations =============== */ + +static int mhuv2_doorbell_rx_startup(struct mhuv2 *mhu, struct mbox_chan *chan) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + + writel_relaxed(BIT(priv->doorbell), + &mhu->recv->ch_wn[priv->ch_wn_idx].mask_clear); + return 0; +} + +static void mhuv2_doorbell_rx_shutdown(struct mhuv2 *mhu, + struct mbox_chan *chan) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + + writel_relaxed(BIT(priv->doorbell), + &mhu->recv->ch_wn[priv->ch_wn_idx].mask_set); +} + +static void *mhuv2_doorbell_read_data(struct mhuv2 *mhu, struct mbox_chan *chan) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + + writel_relaxed(BIT(priv->doorbell), + &mhu->recv->ch_wn[priv->ch_wn_idx].stat_clear); + return NULL; +} + +static int mhuv2_doorbell_last_tx_done(struct mhuv2 *mhu, + struct mbox_chan *chan) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + + return !(readl_relaxed(&mhu->send->ch_wn[priv->ch_wn_idx].stat) & + BIT(priv->doorbell)); +} + +static int mhuv2_doorbell_send_data(struct mhuv2 *mhu, struct mbox_chan *chan, + void *arg) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + unsigned long flags; + + spin_lock_irqsave(&mhu->doorbell_pending_lock, flags); + + priv->pending = 1; + writel_relaxed(BIT(priv->doorbell), + &mhu->send->ch_wn[priv->ch_wn_idx].stat_set); + + spin_unlock_irqrestore(&mhu->doorbell_pending_lock, flags); + + return 0; +} + +static const struct mhuv2_protocol_ops mhuv2_doorbell_ops = { + .rx_startup = mhuv2_doorbell_rx_startup, + .rx_shutdown = mhuv2_doorbell_rx_shutdown, + .read_data = mhuv2_doorbell_read_data, + .last_tx_done = mhuv2_doorbell_last_tx_done, + .send_data = mhuv2_doorbell_send_data, +}; +#define IS_PROTOCOL_DOORBELL(_priv) (_priv->ops == &mhuv2_doorbell_ops) + +/* ============= Data transfer transport protocol operations ================ */ + +static int mhuv2_data_transfer_rx_startup(struct mhuv2 *mhu, + struct mbox_chan *chan) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + int i = priv->ch_wn_idx + priv->windows - 1; + + /* + * The protocol mandates that all but the last status register must be + * masked. + */ + writel_relaxed(0xFFFFFFFF, &mhu->recv->ch_wn[i].mask_clear); + return 0; +} + +static void mhuv2_data_transfer_rx_shutdown(struct mhuv2 *mhu, + struct mbox_chan *chan) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + int i = priv->ch_wn_idx + priv->windows - 1; + + writel_relaxed(0xFFFFFFFF, &mhu->recv->ch_wn[i].mask_set); +} + +static void *mhuv2_data_transfer_read_data(struct mhuv2 *mhu, + struct mbox_chan *chan) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + const int windows = priv->windows; + struct arm_mhuv2_mbox_msg *msg; + u32 *data; + int i, idx; + + msg = kzalloc(sizeof(*msg) + windows * MHUV2_STAT_BYTES, GFP_KERNEL); + if (!msg) + return ERR_PTR(-ENOMEM); + + data = msg->data = msg + 1; + msg->len = windows * MHUV2_STAT_BYTES; + + /* + * Messages are expected in order of most significant word to least + * significant word. Refer mhuv2_data_transfer_send_data() for more + * details. + * + * We also need to read the stat register instead of stat_masked, as we + * masked all but the last window. + * + * Last channel window must be cleared as the final operation. Upon + * clearing the last channel window register, which is unmasked in + * data-transfer protocol, the interrupt is de-asserted. + */ + for (i = 0; i < windows; i++) { + idx = priv->ch_wn_idx + i; + data[windows - 1 - i] = readl_relaxed(&mhu->recv->ch_wn[idx].stat); + writel_relaxed(0xFFFFFFFF, &mhu->recv->ch_wn[idx].stat_clear); + } + + return msg; +} + +static void mhuv2_data_transfer_tx_startup(struct mhuv2 *mhu, + struct mbox_chan *chan) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + int i = priv->ch_wn_idx + priv->windows - 1; + + /* Enable interrupts only for the last window */ + if (mhu->minor) { + writel_relaxed(0x1, &mhu->send->ch_wn[i].int_clr); + writel_relaxed(0x1, &mhu->send->ch_wn[i].int_en); + } +} + +static void mhuv2_data_transfer_tx_shutdown(struct mhuv2 *mhu, + struct mbox_chan *chan) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + int i = priv->ch_wn_idx + priv->windows - 1; + + if (mhu->minor) + writel_relaxed(0x0, &mhu->send->ch_wn[i].int_en); +} + +static int mhuv2_data_transfer_last_tx_done(struct mhuv2 *mhu, + struct mbox_chan *chan) +{ + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + int i = priv->ch_wn_idx + priv->windows - 1; + + /* Just checking the last channel window should be enough */ + return !readl_relaxed(&mhu->send->ch_wn[i].stat); +} + +/* + * Message will be transmitted from most significant to least significant word. + * This is to allow for messages shorter than channel windows to still trigger + * the receiver interrupt which gets activated when the last stat register is + * written. As an example, a 6-word message is to be written on a 4-channel MHU + * connection: Registers marked with '*' are masked, and will not generate an + * interrupt on the receiver side once written. + * + * u32 *data = [0x00000001], [0x00000002], [0x00000003], [0x00000004], + * [0x00000005], [0x00000006] + * + * ROUND 1: + * stat reg To write Write sequence + * [ stat 3 ] <- [0x00000001] 4 <- triggers interrupt on receiver + * [ stat 2 ] <- [0x00000002] 3 + * [ stat 1 ] <- [0x00000003] 2 + * [ stat 0 ] <- [0x00000004] 1 + * + * data += 4 // Increment data pointer by number of stat regs + * + * ROUND 2: + * stat reg To write Write sequence + * [ stat 3 ] <- [0x00000005] 2 <- triggers interrupt on receiver + * [ stat 2 ] <- [0x00000006] 1 + * [ stat 1 ] <- [0x00000000] + * [ stat 0 ] <- [0x00000000] + */ +static int mhuv2_data_transfer_send_data(struct mhuv2 *mhu, + struct mbox_chan *chan, void *arg) +{ + const struct arm_mhuv2_mbox_msg *msg = arg; + int bytes_left = msg->len, bytes_to_send, bytes_in_round, i; + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + int windows = priv->windows; + u32 *data = msg->data, word; + + while (bytes_left) { + if (!data[0]) { + dev_err(mhu->mbox.dev, "Data aligned at first window can't be zero to guarantee interrupt generation at receiver"); + return -EINVAL; + } + + while(!mhuv2_data_transfer_last_tx_done(mhu, chan)) + continue; + + bytes_in_round = min(bytes_left, (int)(windows * MHUV2_STAT_BYTES)); + + for (i = windows - 1; i >= 0; i--) { + /* Data less than windows can transfer ? */ + if (unlikely(bytes_in_round <= i * MHUV2_STAT_BYTES)) + continue; + + word = data[i]; + bytes_to_send = bytes_in_round & (MHUV2_STAT_BYTES - 1); + if (unlikely(bytes_to_send)) + word &= LSB_MASK(bytes_to_send); + else + bytes_to_send = MHUV2_STAT_BYTES; + + writel_relaxed(word, &mhu->send->ch_wn[priv->ch_wn_idx + windows - 1 - i].stat_set); + bytes_left -= bytes_to_send; + bytes_in_round -= bytes_to_send; + } + + data += windows; + } + + return 0; +} + +static const struct mhuv2_protocol_ops mhuv2_data_transfer_ops = { + .rx_startup = mhuv2_data_transfer_rx_startup, + .rx_shutdown = mhuv2_data_transfer_rx_shutdown, + .read_data = mhuv2_data_transfer_read_data, + .tx_startup = mhuv2_data_transfer_tx_startup, + .tx_shutdown = mhuv2_data_transfer_tx_shutdown, + .last_tx_done = mhuv2_data_transfer_last_tx_done, + .send_data = mhuv2_data_transfer_send_data, +}; + +/* Interrupt handlers */ + +static struct mbox_chan *get_irq_chan_comb(struct mhuv2 *mhu, u32 __iomem *reg) +{ + struct mbox_chan *chans = mhu->mbox.chans; + int channel = 0, i, offset = 0, windows, protocol, ch_wn; + u32 stat; + + for (i = 0; i < MHUV2_CMB_INT_ST_REG_CNT; i++) { + stat = readl_relaxed(reg + i); + if (!stat) + continue; + + ch_wn = i * MHUV2_STAT_BITS + __builtin_ctz(stat); + + for (i = 0; i < mhu->length; i += 2) { + protocol = mhu->protocols[i]; + windows = mhu->protocols[i + 1]; + + if (ch_wn >= offset + windows) { + if (protocol == DOORBELL) + channel += MHUV2_STAT_BITS * windows; + else + channel++; + + offset += windows; + continue; + } + + /* Return first chan of the window in doorbell mode */ + if (protocol == DOORBELL) + channel += MHUV2_STAT_BITS * (ch_wn - offset); + + return &chans[channel]; + } + } + + return ERR_PTR(-EIO); +} + +static irqreturn_t mhuv2_sender_interrupt(int irq, void *data) +{ + struct mhuv2 *mhu = data; + struct device *dev = mhu->mbox.dev; + struct mhuv2_mbox_chan_priv *priv; + struct mbox_chan *chan; + unsigned long flags; + int i, found = 0; + u32 stat; + + chan = get_irq_chan_comb(mhu, mhu->send->chcomb_int_st); + if (IS_ERR(chan)) { + dev_warn(dev, "Failed to find channel for the Tx interrupt\n"); + return IRQ_NONE; + } + priv = chan->con_priv; + + if (!IS_PROTOCOL_DOORBELL(priv)) { + writel_relaxed(1, &mhu->send->ch_wn[priv->ch_wn_idx + priv->windows - 1].int_clr); + + if (chan->cl) { + mbox_chan_txdone(chan, 0); + return IRQ_HANDLED; + } + + dev_warn(dev, "Tx interrupt Received on channel (%u) not currently attached to a mailbox client\n", + priv->ch_wn_idx); + return IRQ_NONE; + } + + /* Clear the interrupt first, so we don't miss any doorbell later */ + writel_relaxed(1, &mhu->send->ch_wn[priv->ch_wn_idx].int_clr); + + /* + * In Doorbell mode, make sure no new transitions happen while the + * interrupt handler is trying to find the finished doorbell tx + * operations, else we may think few of the transfers were complete + * before they actually were. + */ + spin_lock_irqsave(&mhu->doorbell_pending_lock, flags); + + /* + * In case of doorbell mode, the first channel of the window is returned + * by get_irq_chan_comb(). Find all the pending channels here. + */ + stat = readl_relaxed(&mhu->send->ch_wn[priv->ch_wn_idx].stat); + + for (i = 0; i < MHUV2_STAT_BITS; i++) { + priv = chan[i].con_priv; + + /* Find cases where pending was 1, but stat's bit is cleared */ + if (priv->pending ^ ((stat >> i) & 0x1)) { + BUG_ON(!priv->pending); + + if (!chan->cl) { + dev_warn(dev, "Tx interrupt received on doorbell (%u : %u) channel not currently attached to a mailbox client\n", + priv->ch_wn_idx, i); + continue; + } + + mbox_chan_txdone(&chan[i], 0); + priv->pending = 0; + found++; + } + } + + spin_unlock_irqrestore(&mhu->doorbell_pending_lock, flags); + + if (!found) { + /* + * We may have already processed the doorbell in the previous + * iteration if the interrupt came right after we cleared it but + * before we read the stat register. + */ + dev_dbg(dev, "Couldn't find the doorbell (%u) for the Tx interrupt interrupt\n", + priv->ch_wn_idx); + return IRQ_NONE; + } + + return IRQ_HANDLED; +} + +static struct mbox_chan *get_irq_chan_comb_rx(struct mhuv2 *mhu) +{ + struct mhuv2_mbox_chan_priv *priv; + struct mbox_chan *chan; + u32 stat; + + chan = get_irq_chan_comb(mhu, mhu->recv->chcomb_int_st); + if (IS_ERR(chan)) + return chan; + + priv = chan->con_priv; + if (!IS_PROTOCOL_DOORBELL(priv)) + return chan; + + /* + * In case of doorbell mode, the first channel of the window is returned + * by the routine. Find the exact channel here. + */ + stat = readl_relaxed(&mhu->recv->ch_wn[priv->ch_wn_idx].stat_masked); + BUG_ON(!stat); + + return chan + __builtin_ctz(stat); +} + +static struct mbox_chan *get_irq_chan_stat_rx(struct mhuv2 *mhu) +{ + struct mbox_chan *chans = mhu->mbox.chans; + struct mhuv2_mbox_chan_priv *priv; + u32 stat; + int i = 0; + + while (i < mhu->mbox.num_chans) { + priv = chans[i].con_priv; + stat = readl_relaxed(&mhu->recv->ch_wn[priv->ch_wn_idx].stat_masked); + + if (stat) { + if (IS_PROTOCOL_DOORBELL(priv)) + i += __builtin_ctz(stat); + return &chans[i]; + } + + i += IS_PROTOCOL_DOORBELL(priv) ? MHUV2_STAT_BITS : 1; + } + + return ERR_PTR(-EIO); +} + +static struct mbox_chan *get_irq_chan_rx(struct mhuv2 *mhu) +{ + if (!mhu->minor) + return get_irq_chan_stat_rx(mhu); + + return get_irq_chan_comb_rx(mhu); +} + +static irqreturn_t mhuv2_receiver_interrupt(int irq, void *arg) +{ + struct mhuv2 *mhu = arg; + struct mbox_chan *chan = get_irq_chan_rx(mhu); + struct device *dev = mhu->mbox.dev; + struct mhuv2_mbox_chan_priv *priv; + int ret = IRQ_NONE; + void *data; + + if (IS_ERR(chan)) { + dev_warn(dev, "Failed to find channel for the rx interrupt\n"); + return IRQ_NONE; + } + priv = chan->con_priv; + + /* Read and clear the data first */ + data = priv->ops->read_data(mhu, chan); + + if (!chan->cl) { + dev_warn(dev, "Received data on channel (%u) not currently attached to a mailbox client\n", + priv->ch_wn_idx); + } else if (IS_ERR(data)) { + dev_err(dev, "Failed to read data: %lu\n", PTR_ERR(data)); + } else { + mbox_chan_received_data(chan, data); + ret = IRQ_HANDLED; + } + + if (!IS_ERR(data)) + kfree(data); + + return ret; +} + +/* Sender and receiver ops */ +static bool mhuv2_sender_last_tx_done(struct mbox_chan *chan) +{ + struct mhuv2 *mhu = mhu_from_mbox(chan->mbox); + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + + return priv->ops->last_tx_done(mhu, chan); +} + +static int mhuv2_sender_send_data(struct mbox_chan *chan, void *data) +{ + struct mhuv2 *mhu = mhu_from_mbox(chan->mbox); + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + + if (!priv->ops->last_tx_done(mhu, chan)) + return -EBUSY; + + return priv->ops->send_data(mhu, chan, data); +} + +static int mhuv2_sender_startup(struct mbox_chan *chan) +{ + struct mhuv2 *mhu = mhu_from_mbox(chan->mbox); + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + + if (priv->ops->tx_startup) + priv->ops->tx_startup(mhu, chan); + return 0; +} + +static void mhuv2_sender_shutdown(struct mbox_chan *chan) +{ + struct mhuv2 *mhu = mhu_from_mbox(chan->mbox); + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + + if (priv->ops->tx_shutdown) + priv->ops->tx_shutdown(mhu, chan); +} + +static const struct mbox_chan_ops mhuv2_sender_ops = { + .send_data = mhuv2_sender_send_data, + .startup = mhuv2_sender_startup, + .shutdown = mhuv2_sender_shutdown, + .last_tx_done = mhuv2_sender_last_tx_done, +}; + +static int mhuv2_receiver_startup(struct mbox_chan *chan) +{ + struct mhuv2 *mhu = mhu_from_mbox(chan->mbox); + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + + return priv->ops->rx_startup(mhu, chan); +} + +static void mhuv2_receiver_shutdown(struct mbox_chan *chan) +{ + struct mhuv2 *mhu = mhu_from_mbox(chan->mbox); + struct mhuv2_mbox_chan_priv *priv = chan->con_priv; + + priv->ops->rx_shutdown(mhu, chan); +} + +static int mhuv2_receiver_send_data(struct mbox_chan *chan, void *data) +{ + dev_err(chan->mbox->dev, + "Trying to transmit on a receiver MHU frame\n"); + return -EIO; +} + +static bool mhuv2_receiver_last_tx_done(struct mbox_chan *chan) +{ + dev_err(chan->mbox->dev, "Trying to Tx poll on a receiver MHU frame\n"); + return true; +} + +static const struct mbox_chan_ops mhuv2_receiver_ops = { + .send_data = mhuv2_receiver_send_data, + .startup = mhuv2_receiver_startup, + .shutdown = mhuv2_receiver_shutdown, + .last_tx_done = mhuv2_receiver_last_tx_done, +}; + +static struct mbox_chan *mhuv2_mbox_of_xlate(struct mbox_controller *mbox, + const struct of_phandle_args *pa) +{ + struct mhuv2 *mhu = mhu_from_mbox(mbox); + struct mbox_chan *chans = mbox->chans; + int channel = 0, i, offset, doorbell, protocol, windows; + + if (pa->args_count != 2) + return ERR_PTR(-EINVAL); + + offset = pa->args[0]; + doorbell = pa->args[1]; + if (doorbell >= MHUV2_STAT_BITS) + goto out; + + for (i = 0; i < mhu->length; i += 2) { + protocol = mhu->protocols[i]; + windows = mhu->protocols[i + 1]; + + if (protocol == DOORBELL) { + if (offset < windows) + return &chans[channel + MHUV2_STAT_BITS * offset + doorbell]; + + channel += MHUV2_STAT_BITS * windows; + offset -= windows; + } else { + if (offset == 0) { + if (doorbell) + goto out; + + return &chans[channel]; + } + + channel++; + offset--; + } + } + +out: + dev_err(mbox->dev, "Couldn't xlate to a valid channel (%d: %d)\n", + pa->args[0], doorbell); + return ERR_PTR(-ENODEV); +} + +static int mhuv2_verify_protocol(struct mhuv2 *mhu) +{ + struct device *dev = mhu->mbox.dev; + int protocol, windows, channels = 0, total_windows = 0, i; + + for (i = 0; i < mhu->length; i += 2) { + protocol = mhu->protocols[i]; + windows = mhu->protocols[i + 1]; + + if (!windows) { + dev_err(dev, "Window size can't be zero (%d)\n", i); + return -EINVAL; + } + total_windows += windows; + + if (protocol == DOORBELL) { + channels += MHUV2_STAT_BITS * windows; + } else if (protocol == DATA_TRANSFER) { + channels++; + } else { + dev_err(dev, "Invalid protocol (%d) present in %s property at index %d\n", + protocol, MHUV2_PROTOCOL_PROP, i); + return -EINVAL; + } + } + + if (total_windows > mhu->windows) { + dev_err(dev, "Channel windows can't be more than what's implemented by the hardware ( %d: %d)\n", + total_windows, mhu->windows); + return -EINVAL; + } + + mhu->mbox.num_chans = channels; + return 0; +} + +static int mhuv2_allocate_channels(struct mhuv2 *mhu) +{ + struct mbox_controller *mbox = &mhu->mbox; + struct mhuv2_mbox_chan_priv *priv; + struct device *dev = mbox->dev; + struct mbox_chan *chans; + int protocol, windows = 0, next_window = 0, i, j, k; + + chans = devm_kcalloc(dev, mbox->num_chans, sizeof(*chans), GFP_KERNEL); + if (!chans) + return -ENOMEM; + + mbox->chans = chans; + + for (i = 0; i < mhu->length; i += 2) { + next_window += windows; + + protocol = mhu->protocols[i]; + windows = mhu->protocols[i + 1]; + + if (protocol == DATA_TRANSFER) { + priv = devm_kmalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->ch_wn_idx = next_window; + priv->ops = &mhuv2_data_transfer_ops; + priv->windows = windows; + chans++->con_priv = priv; + continue; + } + + for (j = 0; j < windows; j++) { + for (k = 0; k < MHUV2_STAT_BITS; k++) { + priv = devm_kmalloc(dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->ch_wn_idx = next_window + j; + priv->ops = &mhuv2_doorbell_ops; + priv->doorbell = k; + chans++->con_priv = priv; + } + + /* + * Permanently enable interrupt as we can't + * control it per doorbell. + */ + if (mhu->frame == SENDER_FRAME && mhu->minor) + writel_relaxed(0x1, &mhu->send->ch_wn[priv->ch_wn_idx].int_en); + } + } + + /* Make sure we have initialized all channels */ + BUG_ON(chans - mbox->chans != mbox->num_chans); + + return 0; +} + +static int mhuv2_parse_channels(struct mhuv2 *mhu) +{ + struct device *dev = mhu->mbox.dev; + const struct device_node *np = dev->of_node; + int ret, count; + u32 *protocols; + + count = of_property_count_u32_elems(np, MHUV2_PROTOCOL_PROP); + if (count <= 0 || count % 2) { + dev_err(dev, "Invalid %s property (%d)\n", MHUV2_PROTOCOL_PROP, + count); + return -EINVAL; + } + + protocols = devm_kmalloc_array(dev, count, sizeof(*protocols), GFP_KERNEL); + if (!protocols) + return -ENOMEM; + + ret = of_property_read_u32_array(np, MHUV2_PROTOCOL_PROP, protocols, count); + if (ret) { + dev_err(dev, "Failed to read %s property: %d\n", + MHUV2_PROTOCOL_PROP, ret); + return ret; + } + + mhu->protocols = protocols; + mhu->length = count; + + ret = mhuv2_verify_protocol(mhu); + if (ret) + return ret; + + return mhuv2_allocate_channels(mhu); +} + +static int mhuv2_tx_init(struct amba_device *adev, struct mhuv2 *mhu, + void __iomem *reg) +{ + struct device *dev = mhu->mbox.dev; + int ret, i; + + mhu->frame = SENDER_FRAME; + mhu->mbox.ops = &mhuv2_sender_ops; + mhu->send = reg; + + mhu->windows = readl_relaxed_bitfield(&mhu->send->mhu_cfg, struct mhu_cfg_t, num_ch); + mhu->minor = readl_relaxed_bitfield(&mhu->send->aidr, struct aidr_t, arch_minor_rev); + + spin_lock_init(&mhu->doorbell_pending_lock); + + /* + * For minor version 1 and forward, tx interrupt is provided by + * the controller. + */ + if (mhu->minor && adev->irq[0]) { + ret = devm_request_threaded_irq(dev, adev->irq[0], NULL, + mhuv2_sender_interrupt, + IRQF_ONESHOT, "mhuv2-tx", mhu); + if (ret) { + dev_err(dev, "Failed to request tx IRQ, fallback to polling mode: %d\n", + ret); + } else { + mhu->mbox.txdone_irq = true; + mhu->mbox.txdone_poll = false; + mhu->irq = adev->irq[0]; + + writel_relaxed_bitfield(1, &mhu->send->int_en, struct int_en_t, chcomb); + + /* Disable all channel interrupts */ + for (i = 0; i < mhu->windows; i++) + writel_relaxed(0x0, &mhu->send->ch_wn[i].int_en); + + goto out; + } + } + + mhu->mbox.txdone_irq = false; + mhu->mbox.txdone_poll = true; + mhu->mbox.txpoll_period = 1; + +out: + /* Wait for receiver to be ready */ + writel_relaxed(0x1, &mhu->send->access_request); + while (!readl_relaxed(&mhu->send->access_ready)) + continue; + + return 0; +} + +static int mhuv2_rx_init(struct amba_device *adev, struct mhuv2 *mhu, + void __iomem *reg) +{ + struct device *dev = mhu->mbox.dev; + int ret, i; + + mhu->frame = RECEIVER_FRAME; + mhu->mbox.ops = &mhuv2_receiver_ops; + mhu->recv = reg; + + mhu->windows = readl_relaxed_bitfield(&mhu->recv->mhu_cfg, struct mhu_cfg_t, num_ch); + mhu->minor = readl_relaxed_bitfield(&mhu->recv->aidr, struct aidr_t, arch_minor_rev); + + mhu->irq = adev->irq[0]; + if (!mhu->irq) { + dev_err(dev, "Missing receiver IRQ\n"); + return -EINVAL; + } + + ret = devm_request_threaded_irq(dev, mhu->irq, NULL, + mhuv2_receiver_interrupt, IRQF_ONESHOT, + "mhuv2-rx", mhu); + if (ret) { + dev_err(dev, "Failed to request rx IRQ\n"); + return ret; + } + + /* Mask all the channel windows */ + for (i = 0; i < mhu->windows; i++) + writel_relaxed(0xFFFFFFFF, &mhu->recv->ch_wn[i].mask_set); + + if (mhu->minor) + writel_relaxed_bitfield(1, &mhu->recv->int_en, struct int_en_t, chcomb); + + return 0; +} + +static int mhuv2_probe(struct amba_device *adev, const struct amba_id *id) +{ + struct device *dev = &adev->dev; + const struct device_node *np = dev->of_node; + struct mhuv2 *mhu; + void __iomem *reg; + int ret = -EINVAL; + + reg = devm_of_iomap(dev, dev->of_node, 0, NULL); + if (IS_ERR(reg)) + return PTR_ERR(reg); + + mhu = devm_kzalloc(dev, sizeof(*mhu), GFP_KERNEL); + if (!mhu) + return -ENOMEM; + + mhu->mbox.dev = dev; + mhu->mbox.of_xlate = mhuv2_mbox_of_xlate; + + if (of_device_is_compatible(np, "arm,mhuv2-tx")) + ret = mhuv2_tx_init(adev, mhu, reg); + else if (of_device_is_compatible(np, "arm,mhuv2-rx")) + ret = mhuv2_rx_init(adev, mhu, reg); + else + dev_err(dev, "Invalid compatible property\n"); + + if (ret) + return ret; + + /* Channel windows can't be 0 */ + BUG_ON(!mhu->windows); + + ret = mhuv2_parse_channels(mhu); + if (ret) + return ret; + + amba_set_drvdata(adev, mhu); + + ret = devm_mbox_controller_register(dev, &mhu->mbox); + if (ret) + dev_err(dev, "failed to register ARM MHUv2 driver %d\n", ret); + + return ret; +} + +static void mhuv2_remove(struct amba_device *adev) +{ + struct mhuv2 *mhu = amba_get_drvdata(adev); + + if (mhu->frame == SENDER_FRAME) + writel_relaxed(0x0, &mhu->send->access_request); +} + +static struct amba_id mhuv2_ids[] = { + { + /* 2.0 */ + .id = 0xbb0d1, + .mask = 0xfffff, + }, + { + /* 2.1 */ + .id = 0xbb076, + .mask = 0xfffff, + }, + { 0, 0 }, +}; +MODULE_DEVICE_TABLE(amba, mhuv2_ids); + +static struct amba_driver mhuv2_driver = { + .drv = { + .name = "arm-mhuv2", + }, + .id_table = mhuv2_ids, + .probe = mhuv2_probe, + .remove = mhuv2_remove, +}; +module_amba_driver(mhuv2_driver); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("ARM MHUv2 Driver"); +MODULE_AUTHOR("Viresh Kumar <viresh.kumar@linaro.org>"); +MODULE_AUTHOR("Tushar Khandelwal <tushar.khandelwal@arm.com>"); 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