diff options
Diffstat (limited to 'drivers/soc/qcom/smd.c')
| -rw-r--r-- | drivers/soc/qcom/smd.c | 1327 |
1 files changed, 1327 insertions, 0 deletions
diff --git a/drivers/soc/qcom/smd.c b/drivers/soc/qcom/smd.c new file mode 100644 index 000000000..a6155c917 --- /dev/null +++ b/drivers/soc/qcom/smd.c @@ -0,0 +1,1327 @@ +/* + * 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_word; + +#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 = 14, + .info_base_id = 266, + .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 + * @tx_info: byte aligned outgoing channel info + * @rx_info: byte aligned incoming channel info + * @tx_info_word: word aligned outgoing channel info + * @rx_info_word: word aligned 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 *tx_info; + struct smd_channel_info *rx_info; + + struct smd_channel_info_word *tx_info_word; + struct smd_channel_info_word *rx_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 { + u32 state; + u8 fDSR; + u8 fCTS; + u8 fCD; + u8 fRI; + u8 fHEAD; + u8 fTAIL; + u8 fSTATE; + u8 fBLOCKREADINTR; + u32 tail; + u32 head; +}; + +/* + * Format of the smd_info smem items, for word aligned channels. + */ +struct smd_channel_info_word { + u32 state; + u32 fDSR; + u32 fCTS; + u32 fCD; + u32 fRI; + u32 fHEAD; + u32 fTAIL; + u32 fSTATE; + u32 fBLOCKREADINTR; + u32 tail; + u32 head; +}; + +#define GET_RX_CHANNEL_INFO(channel, param) \ + (channel->rx_info_word ? \ + channel->rx_info_word->param : \ + channel->rx_info->param) + +#define SET_RX_CHANNEL_INFO(channel, param, value) \ + (channel->rx_info_word ? \ + (channel->rx_info_word->param = value) : \ + (channel->rx_info->param = value)) + +#define GET_TX_CHANNEL_INFO(channel, param) \ + (channel->tx_info_word ? \ + channel->tx_info_word->param : \ + channel->tx_info->param) + +#define SET_TX_CHANNEL_INFO(channel, param, value) \ + (channel->tx_info_word ? \ + (channel->tx_info_word->param = value) : \ + (channel->tx_info->param = 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]; + u32 cid; + u32 flags; + u32 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_INFO(channel, fDSR, 0); + SET_TX_CHANNEL_INFO(channel, fCTS, 0); + SET_TX_CHANNEL_INFO(channel, fCD, 0); + SET_TX_CHANNEL_INFO(channel, fRI, 0); + SET_TX_CHANNEL_INFO(channel, fHEAD, 0); + SET_TX_CHANNEL_INFO(channel, fTAIL, 0); + SET_TX_CHANNEL_INFO(channel, fSTATE, 1); + SET_TX_CHANNEL_INFO(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_INFO(channel, fDSR, is_open); + SET_TX_CHANNEL_INFO(channel, fCTS, is_open); + SET_TX_CHANNEL_INFO(channel, fCD, is_open); + + SET_TX_CHANNEL_INFO(channel, state, state); + SET_TX_CHANNEL_INFO(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) +{ + u32 *dst = (u32 *)_dst; + u32 *src = (u32 *)_src; + + if (word_aligned) { + count /= sizeof(u32); + while (count--) + writel_relaxed(*src++, dst++); + } 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++ = readl_relaxed(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->rx_info_word != NULL; + 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; + u32 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_INFO(channel, fSTATE, 0); + + /* Signal waiting qcom_smd_send() about the interrupt */ + if (!GET_TX_CHANNEL_INFO(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_INFO(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 = 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_INFO(channel, fTAIL, 1); + + /* Signal the remote that we've consumed the data (if requested) */ + if (!GET_RX_CHANNEL_INFO(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->tx_info_word != NULL; + 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) +{ + u32 hdr[5] = {len,}; + int tlen = sizeof(hdr) + len; + int ret; + + /* Word aligned channels only accept word size aligned data */ + if (channel->rx_info_word != NULL && len % 4) + 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_INFO(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_INFO(channel, fBLOCKREADINTR, 1); + } + + SET_TX_CHANNEL_INFO(channel, fTAIL, 0); + + qcom_smd_write_fifo(channel, hdr, sizeof(hdr)); + qcom_smd_write_fifo(channel, data, len); + + SET_TX_CHANNEL_INFO(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) +{ + 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) { + of_node_put(child); + 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; + + node = qcom_smd_match_channel(edge->of_node, channel->name); + if (!node) { + dev_dbg(smd->dev, "no match for '%s'\n", channel->name); + return -ENXIO; + } + + dev_dbg(smd->dev, "registering '%s'\n", channel->name); + + qsdev = kzalloc(sizeof(*qsdev), GFP_KERNEL); + if (!qsdev) + return -ENOMEM; + + dev_set_name(&qsdev->dev, "%s.%s", edge->of_node->name, node->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); + + ret = qcom_smem_get(edge->remote_pid, smem_info_item, (void **)&info, + &info_size); + if (ret) + 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->tx_info_word = info; + channel->rx_info_word = info + sizeof(struct smd_channel_info_word); + } else if (info_size == 2 * sizeof(struct smd_channel_info)) { + channel->tx_info = info; + channel->rx_info = info + sizeof(struct smd_channel_info); + } else { + dev_err(smd->dev, + "channel info of size %zu not supported\n", info_size); + ret = -EINVAL; + goto free_name_and_channel; + } + + ret = qcom_smem_get(edge->remote_pid, smem_fifo_item, &fifo_base, + &fifo_size); + if (ret) + 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 ret; + int tbl; + int i; + + for (tbl = 0; tbl < SMD_ALLOC_TBL_COUNT; tbl++) { + ret = qcom_smem_get(edge->remote_pid, + smem_items[tbl].alloc_tbl_id, + (void **)&alloc_tbl, + NULL); + if (ret < 0) + continue; + + for (i = 0; i < SMD_ALLOC_TBL_SIZE; i++) { + entry = &alloc_tbl[i]; + if (test_bit(i, edge->allocated[tbl])) + continue; + + if (entry->ref_count == 0) + continue; + + if (!entry->name[0]) + continue; + + if (!(entry->flags & SMD_CHANNEL_FLAGS_PACKET)) + continue; + + if ((entry->flags & SMD_CHANNEL_FLAGS_EDGE_MASK) != edge->edge_id) + continue; + + info_id = smem_items[tbl].info_base_id + entry->cid; + fifo_id = smem_items[tbl].fifo_base_id + entry->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; + + /* Wait for smem */ + ret = qcom_smem_get(QCOM_SMEM_HOST_ANY, smem_items[0].alloc_tbl_id, NULL, NULL); + if (ret == -EPROBE_DEFER) + return ret; + + 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"); |