// 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)) {
for (i = 0; i < priv->windows; i++)
writel_relaxed(1, &mhu->send->ch_wn[priv->ch_wn_idx + i].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 <[email protected]>");
MODULE_AUTHOR("Tushar Khandelwal <[email protected]>");
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