[PATCH v3 2/5] soc: qcom: Add Shared Memory Driver
From: Bjorn Andersson
Date: Mon Jul 27 2015 - 23:21:27 EST
This adds the Qualcomm Shared Memory Driver (SMD) providing
communication channels to remote processors, ontop of SMEM.
Signed-off-by: Bjorn Andersson <bjorn.andersson@xxxxxxxxxxxxxx>
---
Changes since v2:
- Made smd copy functions work on words for the word access channels
- Corrected access of smem items from secure heap
- Moved init of smd to postcore
- Minor nits from Georgi on the SMD code
drivers/soc/qcom/Kconfig | 8 +
drivers/soc/qcom/Makefile | 1 +
drivers/soc/qcom/smd.c | 1319 ++++++++++++++++++++++++++++++++++++++++++
include/linux/soc/qcom/smd.h | 46 ++
4 files changed, 1374 insertions(+)
create mode 100644 drivers/soc/qcom/smd.c
create mode 100644 include/linux/soc/qcom/smd.h
diff --git a/drivers/soc/qcom/Kconfig b/drivers/soc/qcom/Kconfig
index 8544e1594c2c..5c1a067b6677 100644
--- a/drivers/soc/qcom/Kconfig
+++ b/drivers/soc/qcom/Kconfig
@@ -18,6 +18,14 @@ config QCOM_PM
modes. It interface with various system drivers to put the cores in
low power modes.
+config QCOM_SMD
+ tristate "Qualcomm Shared Memory Driver (SMD)"
+ depends on QCOM_SMEM
+ help
+ Say y here to enable support for the Qualcomm Shared Memory Driver
+ providing communication channels to remote processors in Qualcomm
+ platforms.
+
config QCOM_SMEM
tristate "Qualcomm Shared Memory Manager (SMEM)"
depends on ARCH_QCOM
diff --git a/drivers/soc/qcom/Makefile b/drivers/soc/qcom/Makefile
index 3a033c43c0ef..f961a8796ed2 100644
--- a/drivers/soc/qcom/Makefile
+++ b/drivers/soc/qcom/Makefile
@@ -1,3 +1,4 @@
obj-$(CONFIG_QCOM_GSBI) += qcom_gsbi.o
obj-$(CONFIG_QCOM_PM) += spm.o
+obj-$(CONFIG_QCOM_SMD) += smd.o
obj-$(CONFIG_QCOM_SMEM) += smem.o
diff --git a/drivers/soc/qcom/smd.c b/drivers/soc/qcom/smd.c
new file mode 100644
index 000000000000..327adcf117c1
--- /dev/null
+++ b/drivers/soc/qcom/smd.c
@@ -0,0 +1,1319 @@
+/*
+ * 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
+ * @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;
+
+ 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, 0);
+ 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->edge_id);
+ 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, 1);
+
+ 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, 0);
+ }
+
+ 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->edge_id, 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->edge_id, 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->edge_id,
+ 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;
+ }
+
+ 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@xxxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Qualcomm Shared Memory Driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/soc/qcom/smd.h b/include/linux/soc/qcom/smd.h
new file mode 100644
index 000000000000..d7e50aa6a4ac
--- /dev/null
+++ b/include/linux/soc/qcom/smd.h
@@ -0,0 +1,46 @@
+#ifndef __QCOM_SMD_H__
+#define __QCOM_SMD_H__
+
+#include <linux/device.h>
+#include <linux/mod_devicetable.h>
+
+struct qcom_smd;
+struct qcom_smd_channel;
+struct qcom_smd_lookup;
+
+/**
+ * struct qcom_smd_device - smd device struct
+ * @dev: the device struct
+ * @channel: handle to the smd channel for this device
+ */
+struct qcom_smd_device {
+ struct device dev;
+ struct qcom_smd_channel *channel;
+};
+
+/**
+ * struct qcom_smd_driver - smd driver struct
+ * @driver: underlying device driver
+ * @probe: invoked when the smd channel is found
+ * @remove: invoked when the smd channel is closed
+ * @callback: invoked when an inbound message is received on the channel,
+ * should return 0 on success or -EBUSY if the data cannot be
+ * consumed at this time
+ */
+struct qcom_smd_driver {
+ struct device_driver driver;
+ int (*probe)(struct qcom_smd_device *dev);
+ void (*remove)(struct qcom_smd_device *dev);
+ int (*callback)(struct qcom_smd_device *, const void *, size_t);
+};
+
+int qcom_smd_driver_register(struct qcom_smd_driver *drv);
+void qcom_smd_driver_unregister(struct qcom_smd_driver *drv);
+
+#define module_qcom_smd_driver(__smd_driver) \
+ module_driver(__smd_driver, qcom_smd_driver_register, \
+ qcom_smd_driver_unregister)
+
+int qcom_smd_send(struct qcom_smd_channel *channel, const void *data, int len);
+
+#endif
--
1.8.2.2
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