/*
* Copyright (c) 2015, Sony Mobile Communications AB.
* Copyright (c) 2012-2013, The Linux Foundation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 and
* only version 2 as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/regmap.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/soc/qcom/smd.h>
#include <linux/soc/qcom/smem.h>
#include <linux/wait.h>
/*
* The Qualcomm Shared Memory communication solution provides point-to-point
* channels for clients to send and receive streaming or packet based data.
*
* Each channel consists of a control item (channel info) and a ring buffer
* pair. The channel info carry information related to channel state, flow
* control and the offsets within the ring buffer.
*
* All allocated channels are listed in an allocation table, identifying the
* pair of items by name, type and remote processor.
*
* Upon creating a new channel the remote processor allocates channel info and
* ring buffer items from the smem heap and populate the allocation table. An
* interrupt is sent to the other end of the channel and a scan for new
* channels should be done. A channel never goes away, it will only change
* state.
*
* The remote processor signals it intent for bring up the communication
* channel by setting the state of its end of the channel to "opening" and
* sends out an interrupt. We detect this change and register a smd device to
* consume the channel. Upon finding a consumer we finish the handshake and the
* channel is up.
*
* Upon closing a channel, the remote processor will update the state of its
* end of the channel and signal us, we will then unregister any attached
* device and close our end of the channel.
*
* Devices attached to a channel can use the qcom_smd_send function to push
* data to the channel, this is done by copying the data into the tx ring
* buffer, updating the pointers in the channel info and signaling the remote
* processor.
*
* The remote processor does the equivalent when it transfer data and upon
* receiving the interrupt we check the channel info for new data and delivers
* this to the attached device. If the device is not ready to receive the data
* we leave it in the ring buffer for now.
*/
struct smd_channel_info;
struct smd_channel_info_pair;
struct smd_channel_info_word;
struct smd_channel_info_word_pair;
#define SMD_ALLOC_TBL_COUNT 2
#define SMD_ALLOC_TBL_SIZE 64
/*
* This lists the various smem heap items relevant for the allocation table and
* smd channel entries.
*/
static const struct {
unsigned alloc_tbl_id;
unsigned info_base_id;
unsigned fifo_base_id;
} smem_items[SMD_ALLOC_TBL_COUNT] = {
{
.alloc_tbl_id = 13,
.info_base_id = 14,
.fifo_base_id = 338
},
{
.alloc_tbl_id = 266,
.info_base_id = 138,
.fifo_base_id = 202,
},
};
/**
* struct qcom_smd_edge - representing a remote processor
* @smd: handle to qcom_smd
* @of_node: of_node handle for information related to this edge
* @edge_id: identifier of this edge
* @remote_pid: identifier of remote processor
* @irq: interrupt for signals on this edge
* @ipc_regmap: regmap handle holding the outgoing ipc register
* @ipc_offset: offset within @ipc_regmap of the register for ipc
* @ipc_bit: bit in the register at @ipc_offset of @ipc_regmap
* @channels: list of all channels detected on this edge
* @channels_lock: guard for modifications of @channels
* @allocated: array of bitmaps representing already allocated channels
* @need_rescan: flag that the @work needs to scan smem for new channels
* @smem_available: last available amount of smem triggering a channel scan
* @work: work item for edge house keeping
*/
struct qcom_smd_edge {
struct qcom_smd *smd;
struct device_node *of_node;
unsigned edge_id;
unsigned remote_pid;
int irq;
struct regmap *ipc_regmap;
int ipc_offset;
int ipc_bit;
struct list_head channels;
spinlock_t channels_lock;
DECLARE_BITMAP(allocated[SMD_ALLOC_TBL_COUNT], SMD_ALLOC_TBL_SIZE);
bool need_rescan;
unsigned smem_available;
struct work_struct work;
};
/*
* SMD channel states.
*/
enum smd_channel_state {
SMD_CHANNEL_CLOSED,
SMD_CHANNEL_OPENING,
SMD_CHANNEL_OPENED,
SMD_CHANNEL_FLUSHING,
SMD_CHANNEL_CLOSING,
SMD_CHANNEL_RESET,
SMD_CHANNEL_RESET_OPENING
};
/**
* struct qcom_smd_channel - smd channel struct
* @edge: qcom_smd_edge this channel is living on
* @qsdev: reference to a associated smd client device
* @name: name of the channel
* @state: local state of the channel
* @remote_state: remote state of the channel
* @info: byte aligned outgoing/incoming channel info
* @info_word: word aligned outgoing/incoming channel info
* @tx_lock: lock to make writes to the channel mutually exclusive
* @fblockread_event: wakeup event tied to tx fBLOCKREADINTR
* @tx_fifo: pointer to the outgoing ring buffer
* @rx_fifo: pointer to the incoming ring buffer
* @fifo_size: size of each ring buffer
* @bounce_buffer: bounce buffer for reading wrapped packets
* @cb: callback function registered for this channel
* @recv_lock: guard for rx info modifications and cb pointer
* @pkt_size: size of the currently handled packet
* @list: lite entry for @channels in qcom_smd_edge
*/
struct qcom_smd_channel {
struct qcom_smd_edge *edge;
struct qcom_smd_device *qsdev;
char *name;
enum smd_channel_state state;
enum smd_channel_state remote_state;
struct smd_channel_info_pair *info;
struct smd_channel_info_word_pair *info_word;
struct mutex tx_lock;
wait_queue_head_t fblockread_event;
void *tx_fifo;
void *rx_fifo;
int fifo_size;
void *bounce_buffer;
int (*cb)(struct qcom_smd_device *, const void *, size_t);
spinlock_t recv_lock;
int pkt_size;
struct list_head list;
};
/**
* struct qcom_smd - smd struct
* @dev: device struct
* @num_edges: number of entries in @edges
* @edges: array of edges to be handled
*/
struct qcom_smd {
struct device *dev;
unsigned num_edges;
struct qcom_smd_edge edges[0];
};
/*
* Format of the smd_info smem items, for byte aligned channels.
*/
struct smd_channel_info {
__le32 state;
u8 fDSR;
u8 fCTS;
u8 fCD;
u8 fRI;
u8 fHEAD;
u8 fTAIL;
u8 fSTATE;
u8 fBLOCKREADINTR;
__le32 tail;
__le32 head;
};
struct smd_channel_info_pair {
struct smd_channel_info tx;
struct smd_channel_info rx;
};
/*
* Format of the smd_info smem items, for word aligned channels.
*/
struct smd_channel_info_word {
__le32 state;
__le32 fDSR;
__le32 fCTS;
__le32 fCD;
__le32 fRI;
__le32 fHEAD;
__le32 fTAIL;
__le32 fSTATE;
__le32 fBLOCKREADINTR;
__le32 tail;
__le32 head;
};
struct smd_channel_info_word_pair {
struct smd_channel_info_word tx;
struct smd_channel_info_word rx;
};
#define GET_RX_CHANNEL_FLAG(channel, param) \
({ \
BUILD_BUG_ON(sizeof(channel->info->rx.param) != sizeof(u8)); \
channel->info_word ? \
le32_to_cpu(channel->info_word->rx.param) : \
channel->info->rx.param; \
})
#define GET_RX_CHANNEL_INFO(channel, param) \
({ \
BUILD_BUG_ON(sizeof(channel->info->rx.param) != sizeof(u32)); \
le32_to_cpu(channel->info_word ? \
channel->info_word->rx.param : \
channel->info->rx.param); \
})
#define SET_RX_CHANNEL_FLAG(channel, param, value) \
({ \
BUILD_BUG_ON(sizeof(channel->info->rx.param) != sizeof(u8)); \
if (channel->info_word) \
channel->info_word->rx.param = cpu_to_le32(value); \
else \
channel->info->rx.param = value; \
})
#define SET_RX_CHANNEL_INFO(channel, param, value) \
({ \
BUILD_BUG_ON(sizeof(channel->info->rx.param) != sizeof(u32)); \
if (channel->info_word) \
channel->info_word->rx.param = cpu_to_le32(value); \
else \
channel->info->rx.param = cpu_to_le32(value); \
})
#define GET_TX_CHANNEL_FLAG(channel, param) \
({ \
BUILD_BUG_ON(sizeof(channel->info->tx.param) != sizeof(u8)); \
channel->info_word ? \
le32_to_cpu(channel->info_word->tx.param) : \
channel->info->tx.param; \
})
#define GET_TX_CHANNEL_INFO(channel, param) \
({ \
BUILD_BUG_ON(sizeof(channel->info->tx.param) != sizeof(u32)); \
le32_to_cpu(channel->info_word ? \
channel->info_word->tx.param : \
channel->info->tx.param); \
})
#define SET_TX_CHANNEL_FLAG(channel, param, value) \
({ \
BUILD_BUG_ON(sizeof(channel->info->tx.param) != sizeof(u8)); \
if (channel->info_word) \
channel->info_word->tx.param = cpu_to_le32(value); \
else \
channel->info->tx.param = value; \
})
#define SET_TX_CHANNEL_INFO(channel, param, value) \
({ \
BUILD_BUG_ON(sizeof(channel->info->tx.param) != sizeof(u32)); \
if (channel->info_word) \
channel->info_word->tx.param = cpu_to_le32(value); \
else \
channel->info->tx.param = cpu_to_le32(value); \
})
/**
* struct qcom_smd_alloc_entry - channel allocation entry
* @name: channel name
* @cid: channel index
* @flags: channel flags and edge id
* @ref_count: reference count of the channel
*/
struct qcom_smd_alloc_entry {
u8 name[20];
__le32 cid;
__le32 flags;
__le32 ref_count;
} __packed;
#define SMD_CHANNEL_FLAGS_EDGE_MASK 0xff
#define SMD_CHANNEL_FLAGS_STREAM BIT(8)
#define SMD_CHANNEL_FLAGS_PACKET BIT(9)
/*
* Each smd packet contains a 20 byte header, with the first 4 being the length
* of the packet.
*/
#define SMD_PACKET_HEADER_LEN 20
/*
* Signal the remote processor associated with 'channel'.
*/
static void qcom_smd_signal_channel(struct qcom_smd_channel *channel)
{
struct qcom_smd_edge *edge = channel->edge;
regmap_write(edge->ipc_regmap, edge->ipc_offset, BIT(edge->ipc_bit));
}
/*
* Initialize the tx channel info
*/
static void qcom_smd_channel_reset(struct qcom_smd_channel *channel)
{
SET_TX_CHANNEL_INFO(channel, state, SMD_CHANNEL_CLOSED);
SET_TX_CHANNEL_FLAG(channel, fDSR, 0);
SET_TX_CHANNEL_FLAG(channel, fCTS, 0);
SET_TX_CHANNEL_FLAG(channel, fCD, 0);
SET_TX_CHANNEL_FLAG(channel, fRI, 0);
SET_TX_CHANNEL_FLAG(channel, fHEAD, 0);
SET_TX_CHANNEL_FLAG(channel, fTAIL, 0);
SET_TX_CHANNEL_FLAG(channel, fSTATE, 1);
SET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR, 1);
SET_TX_CHANNEL_INFO(channel, head, 0);
SET_TX_CHANNEL_INFO(channel, tail, 0);
qcom_smd_signal_channel(channel);
channel->state = SMD_CHANNEL_CLOSED;
channel->pkt_size = 0;
}
/*
* Calculate the amount of data available in the rx fifo
*/
static size_t qcom_smd_channel_get_rx_avail(struct qcom_smd_channel *channel)
{
unsigned head;
unsigned tail;
head = GET_RX_CHANNEL_INFO(channel, head);
tail = GET_RX_CHANNEL_INFO(channel, tail);
return (head - tail) & (channel->fifo_size - 1);
}
/*
* Set tx channel state and inform the remote processor
*/
static void qcom_smd_channel_set_state(struct qcom_smd_channel *channel,
int state)
{
struct qcom_smd_edge *edge = channel->edge;
bool is_open = state == SMD_CHANNEL_OPENED;
if (channel->state == state)
return;
dev_dbg(edge->smd->dev, "set_state(%s, %d)\n", channel->name, state);
SET_TX_CHANNEL_FLAG(channel, fDSR, is_open);
SET_TX_CHANNEL_FLAG(channel, fCTS, is_open);
SET_TX_CHANNEL_FLAG(channel, fCD, is_open);
SET_TX_CHANNEL_INFO(channel, state, state);
SET_TX_CHANNEL_FLAG(channel, fSTATE, 1);
channel->state = state;
qcom_smd_signal_channel(channel);
}
/*
* Copy count bytes of data using 32bit accesses, if that's required.
*/
static void smd_copy_to_fifo(void __iomem *dst,
const void *src,
size_t count,
bool word_aligned)
{
if (word_aligned) {
__iowrite32_copy(dst, src, count / sizeof(u32));
} else {
memcpy_toio(dst, src, count);
}
}
/*
* Copy count bytes of data using 32bit accesses, if that is required.
*/
static void smd_copy_from_fifo(void *_dst,
const void __iomem *_src,
size_t count,
bool word_aligned)
{
u32 *dst = (u32 *)_dst;
u32 *src = (u32 *)_src;
if (word_aligned) {
count /= sizeof(u32);
while (count--)
*dst++ = __raw_readl(src++);
} else {
memcpy_fromio(_dst, _src, count);
}
}
/*
* Read count bytes of data from the rx fifo into buf, but don't advance the
* tail.
*/
static size_t qcom_smd_channel_peek(struct qcom_smd_channel *channel,
void *buf, size_t count)
{
bool word_aligned;
unsigned tail;
size_t len;
word_aligned = channel->info_word;
tail = GET_RX_CHANNEL_INFO(channel, tail);
len = min_t(size_t, count, channel->fifo_size - tail);
if (len) {
smd_copy_from_fifo(buf,
channel->rx_fifo + tail,
len,
word_aligned);
}
if (len != count) {
smd_copy_from_fifo(buf + len,
channel->rx_fifo,
count - len,
word_aligned);
}
return count;
}
/*
* Advance the rx tail by count bytes.
*/
static void qcom_smd_channel_advance(struct qcom_smd_channel *channel,
size_t count)
{
unsigned tail;
tail = GET_RX_CHANNEL_INFO(channel, tail);
tail += count;
tail &= (channel->fifo_size - 1);
SET_RX_CHANNEL_INFO(channel, tail, tail);
}
/*
* Read out a single packet from the rx fifo and deliver it to the device
*/
static int qcom_smd_channel_recv_single(struct qcom_smd_channel *channel)
{
struct qcom_smd_device *qsdev = channel->qsdev;
unsigned tail;
size_t len;
void *ptr;
int ret;
if (!channel->cb)
return 0;
tail = GET_RX_CHANNEL_INFO(channel, tail);
/* Use bounce buffer if the data wraps */
if (tail + channel->pkt_size >= channel->fifo_size) {
ptr = channel->bounce_buffer;
len = qcom_smd_channel_peek(channel, ptr, channel->pkt_size);
} else {
ptr = channel->rx_fifo + tail;
len = channel->pkt_size;
}
ret = channel->cb(qsdev, ptr, len);
if (ret < 0)
return ret;
/* Only forward the tail if the client consumed the data */
qcom_smd_channel_advance(channel, len);
channel->pkt_size = 0;
return 0;
}
/*
* Per channel interrupt handling
*/
static bool qcom_smd_channel_intr(struct qcom_smd_channel *channel)
{
bool need_state_scan = false;
int remote_state;
__le32 pktlen;
int avail;
int ret;
/* Handle state changes */
remote_state = GET_RX_CHANNEL_INFO(channel, state);
if (remote_state != channel->remote_state) {
channel->remote_state = remote_state;
need_state_scan = true;
}
/* Indicate that we have seen any state change */
SET_RX_CHANNEL_FLAG(channel, fSTATE, 0);
/* Signal waiting qcom_smd_send() about the interrupt */
if (!GET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR))
wake_up_interruptible(&channel->fblockread_event);
/* Don't consume any data until we've opened the channel */
if (channel->state != SMD_CHANNEL_OPENED)
goto out;
/* Indicate that we've seen the new data */
SET_RX_CHANNEL_FLAG(channel, fHEAD, 0);
/* Consume data */
for (;;) {
avail = qcom_smd_channel_get_rx_avail(channel);
if (!channel->pkt_size && avail >= SMD_PACKET_HEADER_LEN) {
qcom_smd_channel_peek(channel, &pktlen, sizeof(pktlen));
qcom_smd_channel_advance(channel, SMD_PACKET_HEADER_LEN);
channel->pkt_size = le32_to_cpu(pktlen);
} else if (channel->pkt_size && avail >= channel->pkt_size) {
ret = qcom_smd_channel_recv_single(channel);
if (ret)
break;
} else {
break;
}
}
/* Indicate that we have seen and updated tail */
SET_RX_CHANNEL_FLAG(channel, fTAIL, 1);
/* Signal the remote that we've consumed the data (if requested) */
if (!GET_RX_CHANNEL_FLAG(channel, fBLOCKREADINTR)) {
/* Ensure ordering of channel info updates */
wmb();
qcom_smd_signal_channel(channel);
}
out:
return need_state_scan;
}
/*
* The edge interrupts are triggered by the remote processor on state changes,
* channel info updates or when new channels are created.
*/
static irqreturn_t qcom_smd_edge_intr(int irq, void *data)
{
struct qcom_smd_edge *edge = data;
struct qcom_smd_channel *channel;
unsigned available;
bool kick_worker = false;
/*
* Handle state changes or data on each of the channels on this edge
*/
spin_lock(&edge->channels_lock);
list_for_each_entry(channel, &edge->channels, list) {
spin_lock(&channel->recv_lock);
kick_worker |= qcom_smd_channel_intr(channel);
spin_unlock(&channel->recv_lock);
}
spin_unlock(&edge->channels_lock);
/*
* Creating a new channel requires allocating an smem entry, so we only
* have to scan if the amount of available space in smem have changed
* since last scan.
*/
available = qcom_smem_get_free_space(edge->remote_pid);
if (available != edge->smem_available) {
edge->smem_available = available;
edge->need_rescan = true;
kick_worker = true;
}
if (kick_worker)
schedule_work(&edge->work);
return IRQ_HANDLED;
}
/*
* Delivers any outstanding packets in the rx fifo, can be used after probe of
* the clients to deliver any packets that wasn't delivered before the client
* was setup.
*/
static void qcom_smd_channel_resume(struct qcom_smd_channel *channel)
{
unsigned long flags;
spin_lock_irqsave(&channel->recv_lock, flags);
qcom_smd_channel_intr(channel);
spin_unlock_irqrestore(&channel->recv_lock, flags);
}
/*
* Calculate how much space is available in the tx fifo.
*/
static size_t qcom_smd_get_tx_avail(struct qcom_smd_channel *channel)
{
unsigned head;
unsigned tail;
unsigned mask = channel->fifo_size - 1;
head = GET_TX_CHANNEL_INFO(channel, head);
tail = GET_TX_CHANNEL_INFO(channel, tail);
return mask - ((head - tail) & mask);
}
/*
* Write count bytes of data into channel, possibly wrapping in the ring buffer
*/
static int qcom_smd_write_fifo(struct qcom_smd_channel *channel,
const void *data,
size_t count)
{
bool word_aligned;
unsigned head;
size_t len;
word_aligned = channel->info_word;
head = GET_TX_CHANNEL_INFO(channel, head);
len = min_t(size_t, count, channel->fifo_size - head);
if (len) {
smd_copy_to_fifo(channel->tx_fifo + head,
data,
len,
word_aligned);
}
if (len != count) {
smd_copy_to_fifo(channel->tx_fifo,
data + len,
count - len,
word_aligned);
}
head += count;
head &= (channel->fifo_size - 1);
SET_TX_CHANNEL_INFO(channel, head, head);
return count;
}
/**
* qcom_smd_send - write data to smd channel
* @channel: channel handle
* @data: buffer of data to write
* @len: number of bytes to write
*
* This is a blocking write of len bytes into the channel's tx ring buffer and
* signal the remote end. It will sleep until there is enough space available
* in the tx buffer, utilizing the fBLOCKREADINTR signaling mechanism to avoid
* polling.
*/
int qcom_smd_send(struct qcom_smd_channel *channel, const void *data, int len)
{
__le32 hdr[5] = { cpu_to_le32(len), };
int tlen = sizeof(hdr) + len;
int ret;
/* Word aligned channels only accept word size aligned data */
if (channel->info_word && len % 4)
return -EINVAL;
/* Reject packets that are too big */
if (tlen >= channel->fifo_size)
return -EINVAL;
ret = mutex_lock_interruptible(&channel->tx_lock);
if (ret)
return ret;
while (qcom_smd_get_tx_avail(channel) < tlen) {
if (channel->state != SMD_CHANNEL_OPENED) {
ret = -EPIPE;
goto out;
}
SET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR, 0);
ret = wait_event_interruptible(channel->fblockread_event,
qcom_smd_get_tx_avail(channel) >= tlen ||
channel->state != SMD_CHANNEL_OPENED);
if (ret)
goto out;
SET_TX_CHANNEL_FLAG(channel, fBLOCKREADINTR, 1);
}
SET_TX_CHANNEL_FLAG(channel, fTAIL, 0);
qcom_smd_write_fifo(channel, hdr, sizeof(hdr));
qcom_smd_write_fifo(channel, data, len);
SET_TX_CHANNEL_FLAG(channel, fHEAD, 1);
/* Ensure ordering of channel info updates */
wmb();
qcom_smd_signal_channel(channel);
out:
mutex_unlock(&channel->tx_lock);
return ret;
}
EXPORT_SYMBOL(qcom_smd_send);
static struct qcom_smd_device *to_smd_device(struct device *dev)
{
return container_of(dev, struct qcom_smd_device, dev);
}
static struct qcom_smd_driver *to_smd_driver(struct device *dev)
{
struct qcom_smd_device *qsdev = to_smd_device(dev);
return container_of(qsdev->dev.driver, struct qcom_smd_driver, driver);
}
static int qcom_smd_dev_match(struct device *dev, struct device_driver *drv)
{
struct qcom_smd_device *qsdev = to_smd_device(dev);
struct qcom_smd_driver *qsdrv = container_of(drv, struct qcom_smd_driver, driver);
const struct qcom_smd_id *match = qsdrv->smd_match_table;
const char *name = qsdev->channel->name;
if (match) {
while (match->name[0]) {
if (!strcmp(match->name, name))
return 1;
match++;
}
}
return of_driver_match_device(dev, drv);
}
/*
* Probe the smd client.
*
* The remote side have indicated that it want the channel to be opened, so
* complete the state handshake and probe our client driver.
*/
static int qcom_smd_dev_probe(struct device *dev)
{
struct qcom_smd_device *qsdev = to_smd_device(dev);
struct qcom_smd_driver *qsdrv = to_smd_driver(dev);
struct qcom_smd_channel *channel = qsdev->channel;
size_t bb_size;
int ret;
/*
* Packets are maximum 4k, but reduce if the fifo is smaller
*/
bb_size = min(channel->fifo_size, SZ_4K);
channel->bounce_buffer = kmalloc(bb_size, GFP_KERNEL);
if (!channel->bounce_buffer)
return -ENOMEM;
channel->cb = qsdrv->callback;
qcom_smd_channel_set_state(channel, SMD_CHANNEL_OPENING);
qcom_smd_channel_set_state(channel, SMD_CHANNEL_OPENED);
ret = qsdrv->probe(qsdev);
if (ret)
goto err;
qcom_smd_channel_resume(channel);
return 0;
err:
dev_err(&qsdev->dev, "probe failed\n");
channel->cb = NULL;
kfree(channel->bounce_buffer);
channel->bounce_buffer = NULL;
qcom_smd_channel_set_state(channel, SMD_CHANNEL_CLOSED);
return ret;
}
/*
* Remove the smd client.
*
* The channel is going away, for some reason, so remove the smd client and
* reset the channel state.
*/
static int qcom_smd_dev_remove(struct device *dev)
{
struct qcom_smd_device *qsdev = to_smd_device(dev);
struct qcom_smd_driver *qsdrv = to_smd_driver(dev);
struct qcom_smd_channel *channel = qsdev->channel;
unsigned long flags;
qcom_smd_channel_set_state(channel, SMD_CHANNEL_CLOSING);
/*
* Make sure we don't race with the code receiving data.
*/
spin_lock_irqsave(&channel->recv_lock, flags);
channel->cb = NULL;
spin_unlock_irqrestore(&channel->recv_lock, flags);
/* Wake up any sleepers in qcom_smd_send() */
wake_up_interruptible(&channel->fblockread_event);
/*
* We expect that the client might block in remove() waiting for any
* outstanding calls to qcom_smd_send() to wake up and finish.
*/
if (qsdrv->remove)
qsdrv->remove(qsdev);
/*
* The client is now gone, cleanup and reset the channel state.
*/
channel->qsdev = NULL;
kfree(channel->bounce_buffer);
channel->bounce_buffer = NULL;
qcom_smd_channel_set_state(channel, SMD_CHANNEL_CLOSED);
qcom_smd_channel_reset(channel);
return 0;
}
static struct bus_type qcom_smd_bus = {
.name = "qcom_smd",
.match = qcom_smd_dev_match,
.probe = qcom_smd_dev_probe,
.remove = qcom_smd_dev_remove,
};
/*
* Release function for the qcom_smd_device object.
*/
static void qcom_smd_release_device(struct device *dev)
{
struct qcom_smd_device *qsdev = to_smd_device(dev);
kfree(qsdev);
}
/*
* Finds the device_node for the smd child interested in this channel.
*/
static struct device_node *qcom_smd_match_channel(struct device_node *edge_node,
const char *channel)
{
struct device_node *child;
const char *name;
const char *key;
int ret;
for_each_available_child_of_node(edge_node, child) {
key = "qcom,smd-channels";
ret = of_property_read_string(child, key, &name);
if (ret)
continue;
if (strcmp(name, channel) == 0)
return child;
}
return NULL;
}
/*
* Create a smd client device for channel that is being opened.
*/
static int qcom_smd_create_device(struct qcom_smd_channel *channel)
{
struct qcom_smd_device *qsdev;
struct qcom_smd_edge *edge = channel->edge;
struct device_node *node;
struct qcom_smd *smd = edge->smd;
int ret;
if (channel->qsdev)
return -EEXIST;
dev_dbg(smd->dev, "registering '%s'\n", channel->name);
qsdev = kzalloc(sizeof(*qsdev), GFP_KERNEL);
if (!qsdev)
return -ENOMEM;
node = qcom_smd_match_channel(edge->of_node, channel->name);
dev_set_name(&qsdev->dev, "%s.%s",
edge->of_node->name,
node ? node->name : channel->name);
qsdev->dev.parent = smd->dev;
qsdev->dev.bus = &qcom_smd_bus;
qsdev->dev.release = qcom_smd_release_device;
qsdev->dev.of_node = node;
qsdev->channel = channel;
channel->qsdev = qsdev;
ret = device_register(&qsdev->dev);
if (ret) {
dev_err(smd->dev, "device_register failed: %d\n", ret);
put_device(&qsdev->dev);
}
return ret;
}
/*
* Destroy a smd client device for a channel that's going away.
*/
static void qcom_smd_destroy_device(struct qcom_smd_channel *channel)
{
struct device *dev;
BUG_ON(!channel->qsdev);
dev = &channel->qsdev->dev;
device_unregister(dev);
of_node_put(dev->of_node);
put_device(dev);
}
/**
* qcom_smd_driver_register - register a smd driver
* @qsdrv: qcom_smd_driver struct
*/
int qcom_smd_driver_register(struct qcom_smd_driver *qsdrv)
{
qsdrv->driver.bus = &qcom_smd_bus;
return driver_register(&qsdrv->driver);
}
EXPORT_SYMBOL(qcom_smd_driver_register);
/**
* qcom_smd_driver_unregister - unregister a smd driver
* @qsdrv: qcom_smd_driver struct
*/
void qcom_smd_driver_unregister(struct qcom_smd_driver *qsdrv)
{
driver_unregister(&qsdrv->driver);
}
EXPORT_SYMBOL(qcom_smd_driver_unregister);
/*
* Allocate the qcom_smd_channel object for a newly found smd channel,
* retrieving and validating the smem items involved.
*/
static struct qcom_smd_channel *qcom_smd_create_channel(struct qcom_smd_edge *edge,
unsigned smem_info_item,
unsigned smem_fifo_item,
char *name)
{
struct qcom_smd_channel *channel;
struct qcom_smd *smd = edge->smd;
size_t fifo_size;
size_t info_size;
void *fifo_base;
void *info;
int ret;
channel = devm_kzalloc(smd->dev, sizeof(*channel), GFP_KERNEL);
if (!channel)
return ERR_PTR(-ENOMEM);
channel->edge = edge;
channel->name = devm_kstrdup(smd->dev, name, GFP_KERNEL);
if (!channel->name)
return ERR_PTR(-ENOMEM);
mutex_init(&channel->tx_lock);
spin_lock_init(&channel->recv_lock);
init_waitqueue_head(&channel->fblockread_event);
info = qcom_smem_get(edge->remote_pid, smem_info_item, &info_size);
if (IS_ERR(info)) {
ret = PTR_ERR(info);
goto free_name_and_channel;
}
/*
* Use the size of the item to figure out which channel info struct to
* use.
*/
if (info_size == 2 * sizeof(struct smd_channel_info_word)) {
channel->info_word = info;
} else if (info_size == 2 * sizeof(struct smd_channel_info)) {
channel->info = info;
} else {
dev_err(smd->dev,
"channel info of size %zu not supported\n", info_size);
ret = -EINVAL;
goto free_name_and_channel;
}
fifo_base = qcom_smem_get(edge->remote_pid, smem_fifo_item, &fifo_size);
if (IS_ERR(fifo_base)) {
ret = PTR_ERR(fifo_base);
goto free_name_and_channel;
}
/* The channel consist of a rx and tx fifo of equal size */
fifo_size /= 2;
dev_dbg(smd->dev, "new channel '%s' info-size: %zu fifo-size: %zu\n",
name, info_size, fifo_size);
channel->tx_fifo = fifo_base;
channel->rx_fifo = fifo_base + fifo_size;
channel->fifo_size = fifo_size;
qcom_smd_channel_reset(channel);
return channel;
free_name_and_channel:
devm_kfree(smd->dev, channel->name);
devm_kfree(smd->dev, channel);
return ERR_PTR(ret);
}
/*
* Scans the allocation table for any newly allocated channels, calls
* qcom_smd_create_channel() to create representations of these and add
* them to the edge's list of channels.
*/
static void qcom_discover_channels(struct qcom_smd_edge *edge)
{
struct qcom_smd_alloc_entry *alloc_tbl;
struct qcom_smd_alloc_entry *entry;
struct qcom_smd_channel *channel;
struct qcom_smd *smd = edge->smd;
unsigned long flags;
unsigned fifo_id;
unsigned info_id;
int tbl;
int i;
u32 eflags, cid;
for (tbl = 0; tbl < SMD_ALLOC_TBL_COUNT; tbl++) {
alloc_tbl = qcom_smem_get(edge->remote_pid,
smem_items[tbl].alloc_tbl_id, NULL);
if (IS_ERR(alloc_tbl))
continue;
for (i = 0; i < SMD_ALLOC_TBL_SIZE; i++) {
entry = &alloc_tbl[i];
eflags = le32_to_cpu(entry->flags);
if (test_bit(i, edge->allocated[tbl]))
continue;
if (entry->ref_count == 0)
continue;
if (!entry->name[0])
continue;
if (!(eflags & SMD_CHANNEL_FLAGS_PACKET))
continue;
if ((eflags & SMD_CHANNEL_FLAGS_EDGE_MASK) != edge->edge_id)
continue;
cid = le32_to_cpu(entry->cid);
info_id = smem_items[tbl].info_base_id + cid;
fifo_id = smem_items[tbl].fifo_base_id + cid;
channel = qcom_smd_create_channel(edge, info_id, fifo_id, entry->name);
if (IS_ERR(channel))
continue;
spin_lock_irqsave(&edge->channels_lock, flags);
list_add(&channel->list, &edge->channels);
spin_unlock_irqrestore(&edge->channels_lock, flags);
dev_dbg(smd->dev, "new channel found: '%s'\n", channel->name);
set_bit(i, edge->allocated[tbl]);
}
}
schedule_work(&edge->work);
}
/*
* This per edge worker scans smem for any new channels and register these. It
* then scans all registered channels for state changes that should be handled
* by creating or destroying smd client devices for the registered channels.
*
* LOCKING: edge->channels_lock is not needed to be held during the traversal
* of the channels list as it's done synchronously with the only writer.
*/
static void qcom_channel_state_worker(struct work_struct *work)
{
struct qcom_smd_channel *channel;
struct qcom_smd_edge *edge = container_of(work,
struct qcom_smd_edge,
work);
unsigned remote_state;
/*
* Rescan smem if we have reason to belive that there are new channels.
*/
if (edge->need_rescan) {
edge->need_rescan = false;
qcom_discover_channels(edge);
}
/*
* Register a device for any closed channel where the remote processor
* is showing interest in opening the channel.
*/
list_for_each_entry(channel, &edge->channels, list) {
if (channel->state != SMD_CHANNEL_CLOSED)
continue;
remote_state = GET_RX_CHANNEL_INFO(channel, state);
if (remote_state != SMD_CHANNEL_OPENING &&
remote_state != SMD_CHANNEL_OPENED)
continue;
qcom_smd_create_device(channel);
}
/*
* Unregister the device for any channel that is opened where the
* remote processor is closing the channel.
*/
list_for_each_entry(channel, &edge->channels, list) {
if (channel->state != SMD_CHANNEL_OPENING &&
channel->state != SMD_CHANNEL_OPENED)
continue;
remote_state = GET_RX_CHANNEL_INFO(channel, state);
if (remote_state == SMD_CHANNEL_OPENING ||
remote_state == SMD_CHANNEL_OPENED)
continue;
qcom_smd_destroy_device(channel);
}
}
/*
* Parses an of_node describing an edge.
*/
static int qcom_smd_parse_edge(struct device *dev,
struct device_node *node,
struct qcom_smd_edge *edge)
{
struct device_node *syscon_np;
const char *key;
int irq;
int ret;
INIT_LIST_HEAD(&edge->channels);
spin_lock_init(&edge->channels_lock);
INIT_WORK(&edge->work, qcom_channel_state_worker);
edge->of_node = of_node_get(node);
irq = irq_of_parse_and_map(node, 0);
if (irq < 0) {
dev_err(dev, "required smd interrupt missing\n");
return -EINVAL;
}
ret = devm_request_irq(dev, irq,
qcom_smd_edge_intr, IRQF_TRIGGER_RISING,
node->name, edge);
if (ret) {
dev_err(dev, "failed to request smd irq\n");
return ret;
}
edge->irq = irq;
key = "qcom,smd-edge";
ret = of_property_read_u32(node, key, &edge->edge_id);
if (ret) {
dev_err(dev, "edge missing %s property\n", key);
return -EINVAL;
}
edge->remote_pid = QCOM_SMEM_HOST_ANY;
key = "qcom,remote-pid";
of_property_read_u32(node, key, &edge->remote_pid);
syscon_np = of_parse_phandle(node, "qcom,ipc", 0);
if (!syscon_np) {
dev_err(dev, "no qcom,ipc node\n");
return -ENODEV;
}
edge->ipc_regmap = syscon_node_to_regmap(syscon_np);
if (IS_ERR(edge->ipc_regmap))
return PTR_ERR(edge->ipc_regmap);
key = "qcom,ipc";
ret = of_property_read_u32_index(node, key, 1, &edge->ipc_offset);
if (ret < 0) {
dev_err(dev, "no offset in %s\n", key);
return -EINVAL;
}
ret = of_property_read_u32_index(node, key, 2, &edge->ipc_bit);
if (ret < 0) {
dev_err(dev, "no bit in %s\n", key);
return -EINVAL;
}
return 0;
}
static int qcom_smd_probe(struct platform_device *pdev)
{
struct qcom_smd_edge *edge;
struct device_node *node;
struct qcom_smd *smd;
size_t array_size;
int num_edges;
int ret;
int i = 0;
void *p;
/* Wait for smem */
p = qcom_smem_get(QCOM_SMEM_HOST_ANY, smem_items[0].alloc_tbl_id, NULL);
if (PTR_ERR(p) == -EPROBE_DEFER)
return PTR_ERR(p);
num_edges = of_get_available_child_count(pdev->dev.of_node);
array_size = sizeof(*smd) + num_edges * sizeof(struct qcom_smd_edge);
smd = devm_kzalloc(&pdev->dev, array_size, GFP_KERNEL);
if (!smd)
return -ENOMEM;
smd->dev = &pdev->dev;
smd->num_edges = num_edges;
for_each_available_child_of_node(pdev->dev.of_node, node) {
edge = &smd->edges[i++];
edge->smd = smd;
ret = qcom_smd_parse_edge(&pdev->dev, node, edge);
if (ret)
continue;
edge->need_rescan = true;
schedule_work(&edge->work);
}
platform_set_drvdata(pdev, smd);
return 0;
}
/*
* Shut down all smd clients by making sure that each edge stops processing
* events and scanning for new channels, then call destroy on the devices.
*/
static int qcom_smd_remove(struct platform_device *pdev)
{
struct qcom_smd_channel *channel;
struct qcom_smd_edge *edge;
struct qcom_smd *smd = platform_get_drvdata(pdev);
int i;
for (i = 0; i < smd->num_edges; i++) {
edge = &smd->edges[i];
disable_irq(edge->irq);
cancel_work_sync(&edge->work);
list_for_each_entry(channel, &edge->channels, list) {
if (!channel->qsdev)
continue;
qcom_smd_destroy_device(channel);
}
}
return 0;
}
static const struct of_device_id qcom_smd_of_match[] = {
{ .compatible = "qcom,smd" },
{}
};
MODULE_DEVICE_TABLE(of, qcom_smd_of_match);
static struct platform_driver qcom_smd_driver = {
.probe = qcom_smd_probe,
.remove = qcom_smd_remove,
.driver = {
.name = "qcom-smd",
.of_match_table = qcom_smd_of_match,
},
};
static int __init qcom_smd_init(void)
{
int ret;
ret = bus_register(&qcom_smd_bus);
if (ret) {
pr_err("failed to register smd bus: %d\n", ret);
return ret;
}
return platform_driver_register(&qcom_smd_driver);
}
postcore_initcall(qcom_smd_init);
static void __exit qcom_smd_exit(void)
{
platform_driver_unregister(&qcom_smd_driver);
bus_unregister(&qcom_smd_bus);
}
module_exit(qcom_smd_exit);
MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@sonymobile.com>");
MODULE_DESCRIPTION("Qualcomm Shared Memory Driver");
MODULE_LICENSE("GPL v2");