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Subject[PATCH v2 2/2] rpmsg: Introduce Qualcomm RPM glink driver
Date
This introduces a basic driver for communicating over "native glink"
with the RPM found in Qualcomm platforms.

Tested-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
---

Changes since v1:
- Depend on HAS_IOMEM, for UM build failure
- Wrap read/write indices on >= size, to keep the values valid when message
aligns with end of fifo.

drivers/rpmsg/Kconfig | 9 +
drivers/rpmsg/Makefile | 1 +
drivers/rpmsg/qcom_glink_rpm.c | 1249 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 1259 insertions(+)
create mode 100644 drivers/rpmsg/qcom_glink_rpm.c

diff --git a/drivers/rpmsg/Kconfig b/drivers/rpmsg/Kconfig
index f12ac0b28263..ac126b8b7736 100644
--- a/drivers/rpmsg/Kconfig
+++ b/drivers/rpmsg/Kconfig
@@ -13,6 +13,15 @@ config RPMSG_CHAR
in /dev. They make it possible for user-space programs to send and
receive rpmsg packets.

+config RPMSG_QCOM_GLINK_RPM
+ tristate "Qualcomm RPM Glink driver"
+ select RPMSG
+ depends on HAS_IOMEM
+ help
+ Say y here to enable support for the GLINK RPM communication driver,
+ which serves as a channel for communication with the RPM in GLINK
+ enabled systems.
+
config RPMSG_QCOM_SMD
tristate "Qualcomm Shared Memory Driver (SMD)"
depends on QCOM_SMEM
diff --git a/drivers/rpmsg/Makefile b/drivers/rpmsg/Makefile
index fae9a6d548fb..28cc19088cc0 100644
--- a/drivers/rpmsg/Makefile
+++ b/drivers/rpmsg/Makefile
@@ -1,4 +1,5 @@
obj-$(CONFIG_RPMSG) += rpmsg_core.o
obj-$(CONFIG_RPMSG_CHAR) += rpmsg_char.o
+obj-$(CONFIG_RPMSG_QCOM_GLINK_RPM) += qcom_glink_rpm.o
obj-$(CONFIG_RPMSG_QCOM_SMD) += qcom_smd.o
obj-$(CONFIG_RPMSG_VIRTIO) += virtio_rpmsg_bus.o
diff --git a/drivers/rpmsg/qcom_glink_rpm.c b/drivers/rpmsg/qcom_glink_rpm.c
new file mode 100644
index 000000000000..a99e6c671323
--- /dev/null
+++ b/drivers/rpmsg/qcom_glink_rpm.c
@@ -0,0 +1,1249 @@
+/*
+ * Copyright (c) 2016-2017, Linaro Ltd
+ *
+ * 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/idr.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/list.h>
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_address.h>
+#include <linux/platform_device.h>
+#include <linux/regmap.h>
+#include <linux/rpmsg.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+#include "rpmsg_internal.h"
+
+#define RPM_TOC_SIZE 256
+#define RPM_TOC_MAGIC 0x67727430 /* grt0 */
+#define RPM_TOC_MAX_ENTRIES ((RPM_TOC_SIZE - sizeof(struct rpm_toc)) / \
+ sizeof(struct rpm_toc_entry))
+
+#define RPM_TX_FIFO_ID 0x61703272 /* ap2r */
+#define RPM_RX_FIFO_ID 0x72326170 /* r2ap */
+
+#define GLINK_NAME_SIZE 32
+
+#define RPM_GLINK_CID_MIN 1
+#define RPM_GLINK_CID_MAX 65536
+
+struct rpm_toc_entry {
+ __le32 id;
+ __le32 offset;
+ __le32 size;
+} __packed;
+
+struct rpm_toc {
+ __le32 magic;
+ __le32 count;
+
+ struct rpm_toc_entry entries[];
+} __packed;
+
+struct glink_msg {
+ __le16 cmd;
+ __le16 param1;
+ __le32 param2;
+ u8 data[];
+} __packed;
+
+struct glink_rpm_pipe {
+ void __iomem *tail;
+ void __iomem *head;
+
+ void __iomem *fifo;
+
+ size_t length;
+};
+
+/**
+ * struct glink_defer_cmd - deferred incoming control message
+ * @node: list node
+ * @msg: message header
+ * data: payload of the message
+ *
+ * Copy of a received control message, to be added to @rx_queue and processed
+ * by @rx_work of @glink_rpm.
+ */
+struct glink_defer_cmd {
+ struct list_head node;
+
+ struct glink_msg msg;
+ u8 data[];
+};
+
+/**
+ * struct glink_rpm - driver context, relates to one remote subsystem
+ * @dev: reference to the associated struct device
+ * @ipc_regmap: regmap for signaling remote
+ * @ipc_offset: offset in @ipc_regmap for signaling remote
+ * @ipc_bit: bit in @ipc_offset for signaling remote
+ * @rx_pipe: pipe object for receive FIFO
+ * @tx_pipe: pipe object for transmit FIFO
+ * @irq: IRQ for signaling incoming events
+ * @rx_work: worker for handling received control messages
+ * @rx_lock: protects the @rx_queue
+ * @rx_queue: queue of received control messages to be processed in @rx_work
+ * @tx_lock: synchronizes operations on the tx fifo
+ * @idr_lock: synchronizes @lcids and @rcids modifications
+ * @lcids: idr of all channels with a known local channel id
+ * @rcids: idr of all channels with a known remote channel id
+ */
+struct glink_rpm {
+ struct device *dev;
+
+ struct regmap *ipc_regmap;
+ unsigned int ipc_offset;
+ unsigned int ipc_bit;
+
+ struct glink_rpm_pipe rx_pipe;
+ struct glink_rpm_pipe tx_pipe;
+
+ int irq;
+
+ struct work_struct rx_work;
+ spinlock_t rx_lock;
+ struct list_head rx_queue;
+
+ struct mutex tx_lock;
+
+ struct mutex idr_lock;
+ struct idr lcids;
+ struct idr rcids;
+};
+
+enum {
+ GLINK_STATE_CLOSED,
+ GLINK_STATE_OPENING,
+ GLINK_STATE_OPEN,
+ GLINK_STATE_CLOSING,
+};
+
+/**
+ * struct glink_channel - internal representation of a channel
+ * @rpdev: rpdev reference, only used for primary endpoints
+ * @ept: rpmsg endpoint this channel is associated with
+ * @glink: glink_rpm context handle
+ * @refcount: refcount for the channel object
+ * @recv_lock: guard for @ept.cb
+ * @name: unique channel name/identifier
+ * @lcid: channel id, in local space
+ * @rcid: channel id, in remote space
+ * @buf: receive buffer, for gathering fragments
+ * @buf_offset: write offset in @buf
+ * @buf_size: size of current @buf
+ * @open_ack: completed once remote has acked the open-request
+ * @open_req: completed once open-request has been received
+ */
+struct glink_channel {
+ struct rpmsg_endpoint ept;
+
+ struct rpmsg_device *rpdev;
+ struct glink_rpm *glink;
+
+ struct kref refcount;
+
+ spinlock_t recv_lock;
+
+ char *name;
+ unsigned int lcid;
+ unsigned int rcid;
+
+ void *buf;
+ int buf_offset;
+ int buf_size;
+
+ struct completion open_ack;
+ struct completion open_req;
+};
+
+#define to_glink_channel(_ept) container_of(_ept, struct glink_channel, ept)
+
+static const struct rpmsg_endpoint_ops glink_endpoint_ops;
+
+#define RPM_CMD_VERSION 0
+#define RPM_CMD_VERSION_ACK 1
+#define RPM_CMD_OPEN 2
+#define RPM_CMD_CLOSE 3
+#define RPM_CMD_OPEN_ACK 4
+#define RPM_CMD_TX_DATA 9
+#define RPM_CMD_CLOSE_ACK 11
+#define RPM_CMD_TX_DATA_CONT 12
+#define RPM_CMD_READ_NOTIF 13
+
+#define GLINK_FEATURE_INTENTLESS BIT(1)
+
+static struct glink_channel *glink_rpm_alloc_channel(struct glink_rpm *glink,
+ const char *name)
+{
+ struct glink_channel *channel;
+
+ channel = kzalloc(sizeof(*channel), GFP_KERNEL);
+ if (!channel)
+ return ERR_PTR(-ENOMEM);
+
+ /* Setup glink internal glink_channel data */
+ spin_lock_init(&channel->recv_lock);
+ channel->glink = glink;
+ channel->name = kstrdup(name, GFP_KERNEL);
+
+ init_completion(&channel->open_req);
+ init_completion(&channel->open_ack);
+
+ kref_init(&channel->refcount);
+
+ return channel;
+}
+
+static void glink_rpm_channel_release(struct kref *ref)
+{
+ struct glink_channel *channel = container_of(ref, struct glink_channel,
+ refcount);
+
+ kfree(channel->name);
+ kfree(channel);
+}
+
+static size_t glink_rpm_rx_avail(struct glink_rpm *glink)
+{
+ struct glink_rpm_pipe *pipe = &glink->rx_pipe;
+ unsigned int head;
+ unsigned int tail;
+
+ head = readl(pipe->head);
+ tail = readl(pipe->tail);
+
+ if (head < tail)
+ return pipe->length - tail + head;
+ else
+ return head - tail;
+}
+
+static void glink_rpm_rx_peak(struct glink_rpm *glink,
+ void *data, size_t count)
+{
+ struct glink_rpm_pipe *pipe = &glink->rx_pipe;
+ unsigned int tail;
+ size_t len;
+
+ tail = readl(pipe->tail);
+
+ len = min_t(size_t, count, pipe->length - tail);
+ if (len) {
+ __ioread32_copy(data, pipe->fifo + tail,
+ len / sizeof(u32));
+ }
+
+ if (len != count) {
+ __ioread32_copy(data + len, pipe->fifo,
+ (count - len) / sizeof(u32));
+ }
+}
+
+static void glink_rpm_rx_advance(struct glink_rpm *glink,
+ size_t count)
+{
+ struct glink_rpm_pipe *pipe = &glink->rx_pipe;
+ unsigned int tail;
+
+ tail = readl(pipe->tail);
+
+ tail += count;
+ if (tail >= pipe->length)
+ tail -= pipe->length;
+
+ writel(tail, pipe->tail);
+}
+
+static size_t glink_rpm_tx_avail(struct glink_rpm *glink)
+{
+ struct glink_rpm_pipe *pipe = &glink->tx_pipe;
+ unsigned int head;
+ unsigned int tail;
+
+ head = readl(pipe->head);
+ tail = readl(pipe->tail);
+
+ if (tail <= head)
+ return pipe->length - head + tail;
+ else
+ return tail - head;
+}
+
+static unsigned int glink_rpm_tx_write(struct glink_rpm *glink,
+ unsigned int head,
+ const void *data, size_t count)
+{
+ struct glink_rpm_pipe *pipe = &glink->tx_pipe;
+ size_t len;
+
+ len = min_t(size_t, count, pipe->length - head);
+ if (len) {
+ __iowrite32_copy(pipe->fifo + head, data,
+ len / sizeof(u32));
+ }
+
+ if (len != count) {
+ __iowrite32_copy(pipe->fifo, data + len,
+ (count - len) / sizeof(u32));
+ }
+
+ head += count;
+ if (head >= pipe->length)
+ head -= pipe->length;
+
+ return head;
+}
+
+static void glink_rpm_kick(struct glink_rpm *glink)
+{
+ /* Ensure ordering with any previous writes */
+ wmb();
+
+ regmap_write(glink->ipc_regmap, glink->ipc_offset, BIT(glink->ipc_bit));
+}
+
+static int glink_rpm_tx(struct glink_rpm *glink,
+ const void *hdr, size_t hlen,
+ const void *data, size_t dlen, bool wait)
+{
+ struct glink_rpm_pipe *pipe = &glink->tx_pipe;
+ unsigned int head;
+ unsigned int tlen = hlen + dlen;
+ int ret;
+
+ /* Reject packets that are too big */
+ if (tlen >= glink->tx_pipe.length)
+ return -EINVAL;
+
+ if (WARN(tlen % 8, "Unaligned TX request"))
+ return -EINVAL;
+
+ ret = mutex_lock_interruptible(&glink->tx_lock);
+ if (ret)
+ return ret;
+
+ while (glink_rpm_tx_avail(glink) < tlen) {
+ if (!wait) {
+ ret = -ENOMEM;
+ goto out;
+ }
+
+ msleep(10);
+ }
+
+ head = readl(pipe->head);
+ head = glink_rpm_tx_write(glink, head, hdr, hlen);
+ head = glink_rpm_tx_write(glink, head, data, dlen);
+ writel(head, pipe->head);
+
+ glink_rpm_kick(glink);
+
+out:
+ mutex_unlock(&glink->tx_lock);
+
+ return ret;
+}
+
+static int glink_rpm_send_version(struct glink_rpm *glink)
+{
+ struct glink_msg msg;
+
+ msg.cmd = cpu_to_le16(RPM_CMD_VERSION);
+ msg.param1 = cpu_to_le16(1);
+ msg.param2 = cpu_to_le32(GLINK_FEATURE_INTENTLESS);
+
+ return glink_rpm_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+static void glink_rpm_send_version_ack(struct glink_rpm *glink)
+{
+ struct glink_msg msg;
+
+ msg.cmd = cpu_to_le16(RPM_CMD_VERSION_ACK);
+ msg.param1 = cpu_to_le16(1);
+ msg.param2 = cpu_to_le32(0);
+
+ glink_rpm_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+static void glink_rpm_send_open_ack(struct glink_rpm *glink,
+ struct glink_channel *channel)
+{
+ struct glink_msg msg;
+
+ msg.cmd = cpu_to_le16(RPM_CMD_OPEN_ACK);
+ msg.param1 = cpu_to_le16(channel->rcid);
+ msg.param2 = cpu_to_le32(0);
+
+ glink_rpm_tx(glink, &msg, sizeof(msg), NULL, 0, true);
+}
+
+/**
+ * glink_rpm_send_open_req() - send a RPM_CMD_OPEN request to the remote
+ * @glink:
+ * @channel:
+ *
+ * Allocates a local channel id and sends a RPM_CMD_OPEN message to the remote.
+ * Will return with refcount held, regardless of outcome.
+ *
+ * Returns 0 on success, negative errno otherwise.
+ */
+static int glink_rpm_send_open_req(struct glink_rpm *glink,
+ struct glink_channel *channel)
+{
+ struct {
+ struct glink_msg msg;
+ u8 name[GLINK_NAME_SIZE];
+ } __packed req;
+ int name_len = strlen(channel->name) + 1;
+ int req_len = ALIGN(sizeof(req.msg) + name_len, 8);
+ int ret;
+
+ kref_get(&channel->refcount);
+
+ mutex_lock(&glink->idr_lock);
+ ret = idr_alloc_cyclic(&glink->lcids, channel,
+ RPM_GLINK_CID_MIN, RPM_GLINK_CID_MAX, GFP_KERNEL);
+ mutex_unlock(&glink->idr_lock);
+ if (ret < 0)
+ return ret;
+
+ channel->lcid = ret;
+
+ req.msg.cmd = cpu_to_le16(RPM_CMD_OPEN);
+ req.msg.param1 = cpu_to_le16(channel->lcid);
+ req.msg.param2 = cpu_to_le32(name_len);
+ strcpy(req.name, channel->name);
+
+ ret = glink_rpm_tx(glink, &req, req_len, NULL, 0, true);
+ if (ret)
+ goto remove_idr;
+
+ return 0;
+
+remove_idr:
+ mutex_lock(&glink->idr_lock);
+ idr_remove(&glink->lcids, channel->lcid);
+ channel->lcid = 0;
+ mutex_unlock(&glink->idr_lock);
+
+ return ret;
+}
+
+static void glink_rpm_send_close_req(struct glink_rpm *glink,
+ struct glink_channel *channel)
+{
+ struct glink_msg req;
+
+ req.cmd = cpu_to_le16(RPM_CMD_CLOSE);
+ req.param1 = cpu_to_le16(channel->lcid);
+ req.param2 = 0;
+
+ glink_rpm_tx(glink, &req, sizeof(req), NULL, 0, true);
+}
+
+static void glink_rpm_send_close_ack(struct glink_rpm *glink, unsigned int rcid)
+{
+ struct glink_msg req;
+
+ req.cmd = cpu_to_le16(RPM_CMD_CLOSE_ACK);
+ req.param1 = cpu_to_le16(rcid);
+ req.param2 = 0;
+
+ glink_rpm_tx(glink, &req, sizeof(req), NULL, 0, true);
+}
+
+static int glink_rpm_rx_defer(struct glink_rpm *glink, size_t extra)
+{
+ struct glink_defer_cmd *dcmd;
+
+ extra = ALIGN(extra, 8);
+
+ if (glink_rpm_rx_avail(glink) < sizeof(struct glink_msg) + extra) {
+ dev_dbg(glink->dev, "Insufficient data in rx fifo");
+ return -ENXIO;
+ }
+
+ dcmd = kzalloc(sizeof(*dcmd) + extra, GFP_ATOMIC);
+ if (!dcmd)
+ return -ENOMEM;
+
+ INIT_LIST_HEAD(&dcmd->node);
+
+ glink_rpm_rx_peak(glink, &dcmd->msg, sizeof(dcmd->msg) + extra);
+
+ spin_lock(&glink->rx_lock);
+ list_add_tail(&dcmd->node, &glink->rx_queue);
+ spin_unlock(&glink->rx_lock);
+
+ schedule_work(&glink->rx_work);
+ glink_rpm_rx_advance(glink, sizeof(dcmd->msg) + extra);
+
+ return 0;
+}
+
+static int glink_rpm_rx_data(struct glink_rpm *glink, size_t avail)
+{
+ struct glink_channel *channel;
+ struct {
+ struct glink_msg msg;
+ __le32 chunk_size;
+ __le32 left_size;
+ } __packed hdr;
+ unsigned int chunk_size;
+ unsigned int left_size;
+ unsigned int rcid;
+
+ if (avail < sizeof(hdr)) {
+ dev_dbg(glink->dev, "Not enough data in fifo\n");
+ return -EAGAIN;
+ }
+
+ glink_rpm_rx_peak(glink, &hdr, sizeof(hdr));
+ chunk_size = le32_to_cpu(hdr.chunk_size);
+ left_size = le32_to_cpu(hdr.left_size);
+
+ if (avail < sizeof(hdr) + chunk_size) {
+ dev_dbg(glink->dev, "Payload not yet in fifo\n");
+ return -EAGAIN;
+ }
+
+ if (WARN(chunk_size % 4, "Incoming data must be word aligned\n"))
+ return -EINVAL;
+
+ rcid = le16_to_cpu(hdr.msg.param1);
+ channel = idr_find(&glink->rcids, rcid);
+ if (!channel) {
+ dev_dbg(glink->dev, "Data on non-existing channel\n");
+
+ /* Drop the message */
+ glink_rpm_rx_advance(glink, ALIGN(sizeof(hdr) + chunk_size, 8));
+ return 0;
+ }
+
+ /* Might have an ongoing, fragmented, message to append */
+ if (!channel->buf) {
+ channel->buf = kmalloc(chunk_size + left_size, GFP_ATOMIC);
+ if (!channel->buf)
+ return -ENOMEM;
+
+ channel->buf_size = chunk_size + left_size;
+ channel->buf_offset = 0;
+ }
+
+ glink_rpm_rx_advance(glink, sizeof(hdr));
+
+ if (channel->buf_size - channel->buf_offset < chunk_size) {
+ dev_err(glink->dev, "Insufficient space in input buffer\n");
+
+ /* The packet header lied, drop payload */
+ glink_rpm_rx_advance(glink, chunk_size);
+ return -ENOMEM;
+ }
+
+ glink_rpm_rx_peak(glink, channel->buf + channel->buf_offset, chunk_size);
+ channel->buf_offset += chunk_size;
+
+ /* Handle message when no fragments remain to be received */
+ if (!left_size) {
+ spin_lock(&channel->recv_lock);
+ if (channel->ept.cb) {
+ channel->ept.cb(channel->ept.rpdev,
+ channel->buf,
+ channel->buf_offset,
+ channel->ept.priv,
+ RPMSG_ADDR_ANY);
+ }
+ spin_unlock(&channel->recv_lock);
+
+ kfree(channel->buf);
+ channel->buf = NULL;
+ channel->buf_size = 0;
+ }
+
+ /* Each message starts at 8 byte aligned address */
+ glink_rpm_rx_advance(glink, ALIGN(chunk_size, 8));
+
+ return 0;
+}
+
+static int glink_rpm_rx_open_ack(struct glink_rpm *glink, unsigned int lcid)
+{
+ struct glink_channel *channel;
+
+ channel = idr_find(&glink->lcids, lcid);
+ if (!channel) {
+ dev_err(glink->dev, "Invalid open ack packet\n");
+ return -EINVAL;
+ }
+
+ complete(&channel->open_ack);
+
+ return 0;
+}
+
+static irqreturn_t glink_rpm_intr(int irq, void *data)
+{
+ struct glink_rpm *glink = data;
+ struct glink_msg msg;
+ unsigned int param1;
+ unsigned int param2;
+ unsigned int avail;
+ unsigned int cmd;
+ int ret;
+
+ for (;;) {
+ avail = glink_rpm_rx_avail(glink);
+ if (avail < sizeof(msg))
+ break;
+
+ glink_rpm_rx_peak(glink, &msg, sizeof(msg));
+
+ cmd = le16_to_cpu(msg.cmd);
+ param1 = le16_to_cpu(msg.param1);
+ param2 = le32_to_cpu(msg.param2);
+
+ switch (cmd) {
+ case RPM_CMD_VERSION:
+ case RPM_CMD_VERSION_ACK:
+ case RPM_CMD_CLOSE:
+ case RPM_CMD_CLOSE_ACK:
+ ret = glink_rpm_rx_defer(glink, 0);
+ break;
+ case RPM_CMD_OPEN_ACK:
+ ret = glink_rpm_rx_open_ack(glink, param1);
+ glink_rpm_rx_advance(glink, ALIGN(sizeof(msg), 8));
+ break;
+ case RPM_CMD_OPEN:
+ ret = glink_rpm_rx_defer(glink, param2);
+ break;
+ case RPM_CMD_TX_DATA:
+ case RPM_CMD_TX_DATA_CONT:
+ ret = glink_rpm_rx_data(glink, avail);
+ break;
+ case RPM_CMD_READ_NOTIF:
+ glink_rpm_rx_advance(glink, ALIGN(sizeof(msg), 8));
+ glink_rpm_kick(glink);
+
+ ret = 0;
+ break;
+ default:
+ dev_err(glink->dev, "unhandled rx cmd: %d\n", cmd);
+ ret = -EINVAL;
+ break;
+ }
+
+ if (ret)
+ break;
+ }
+
+ return IRQ_HANDLED;
+}
+
+/* Locally initiated rpmsg_create_ept */
+static struct glink_channel *glink_rpm_create_local(struct glink_rpm *glink,
+ const char *name)
+{
+ struct glink_channel *channel;
+ int ret;
+
+ channel = glink_rpm_alloc_channel(glink, name);
+ if (IS_ERR(channel))
+ return ERR_CAST(channel);
+
+ ret = glink_rpm_send_open_req(glink, channel);
+ if (ret)
+ goto release_channel;
+
+ ret = wait_for_completion_timeout(&channel->open_ack, 5 * HZ);
+ if (!ret)
+ goto err_timeout;
+
+ ret = wait_for_completion_timeout(&channel->open_req, 5 * HZ);
+ if (!ret)
+ goto err_timeout;
+
+ glink_rpm_send_open_ack(glink, channel);
+
+ return channel;
+
+err_timeout:
+ /* glink_rpm_send_open_req() did register the channel in lcids*/
+ mutex_lock(&glink->idr_lock);
+ idr_remove(&glink->lcids, channel->lcid);
+ mutex_unlock(&glink->idr_lock);
+
+release_channel:
+ /* Release glink_rpm_send_open_req() reference */
+ kref_put(&channel->refcount, glink_rpm_channel_release);
+ /* Release glink_rpm_alloc_channel() reference */
+ kref_put(&channel->refcount, glink_rpm_channel_release);
+
+ return ERR_PTR(-ETIMEDOUT);
+}
+
+/* Remote initiated rpmsg_create_ept */
+static int glink_rpm_create_remote(struct glink_rpm *glink,
+ struct glink_channel *channel)
+{
+ int ret;
+
+ glink_rpm_send_open_ack(glink, channel);
+
+ ret = glink_rpm_send_open_req(glink, channel);
+ if (ret)
+ goto close_link;
+
+ ret = wait_for_completion_timeout(&channel->open_ack, 5 * HZ);
+ if (!ret) {
+ ret = -ETIMEDOUT;
+ goto close_link;
+ }
+
+ return 0;
+
+close_link:
+ /*
+ * Send a close request to "undo" our open-ack. The close-ack will
+ * release the last reference.
+ */
+ glink_rpm_send_close_req(glink, channel);
+
+ /* Release glink_rpm_send_open_req() reference */
+ kref_put(&channel->refcount, glink_rpm_channel_release);
+
+ return ret;
+}
+
+static struct rpmsg_endpoint *glink_rpm_create_ept(struct rpmsg_device *rpdev,
+ rpmsg_rx_cb_t cb, void *priv,
+ struct rpmsg_channel_info chinfo)
+{
+ struct glink_channel *parent = to_glink_channel(rpdev->ept);
+ struct glink_channel *channel;
+ struct glink_rpm *glink = parent->glink;
+ struct rpmsg_endpoint *ept;
+ const char *name = chinfo.name;
+ int cid;
+ int ret;
+
+ idr_for_each_entry(&glink->rcids, channel, cid) {
+ if (!strcmp(channel->name, name))
+ break;
+ }
+
+ if (!channel) {
+ channel = glink_rpm_create_local(glink, name);
+ if (IS_ERR(channel))
+ return NULL;
+ } else {
+ ret = glink_rpm_create_remote(glink, channel);
+ if (ret)
+ return NULL;
+ }
+
+ ept = &channel->ept;
+ ept->rpdev = rpdev;
+ ept->cb = cb;
+ ept->priv = priv;
+ ept->ops = &glink_endpoint_ops;
+
+ return ept;
+}
+
+static void glink_rpm_destroy_ept(struct rpmsg_endpoint *ept)
+{
+ struct glink_channel *channel = to_glink_channel(ept);
+ struct glink_rpm *glink = channel->glink;
+ unsigned long flags;
+
+ spin_lock_irqsave(&channel->recv_lock, flags);
+ channel->ept.cb = NULL;
+ spin_unlock_irqrestore(&channel->recv_lock, flags);
+
+ /* Decouple the potential rpdev from the channel */
+ channel->rpdev = NULL;
+
+ glink_rpm_send_close_req(glink, channel);
+}
+
+static int __glink_rpm_send(struct glink_channel *channel,
+ void *data, int len, bool wait)
+{
+ struct glink_rpm *glink = channel->glink;
+ struct {
+ struct glink_msg msg;
+ __le32 chunk_size;
+ __le32 left_size;
+ } __packed req;
+
+ if (WARN(len % 8, "RPM GLINK expects 8 byte aligned messages\n"))
+ return -EINVAL;
+
+ req.msg.cmd = cpu_to_le16(RPM_CMD_TX_DATA);
+ req.msg.param1 = cpu_to_le16(channel->lcid);
+ req.msg.param2 = cpu_to_le32(channel->rcid);
+ req.chunk_size = cpu_to_le32(len);
+ req.left_size = cpu_to_le32(0);
+
+ return glink_rpm_tx(glink, &req, sizeof(req), data, len, wait);
+}
+
+static int glink_rpm_send(struct rpmsg_endpoint *ept, void *data, int len)
+{
+ struct glink_channel *channel = to_glink_channel(ept);
+
+ return __glink_rpm_send(channel, data, len, true);
+}
+
+static int glink_rpm_trysend(struct rpmsg_endpoint *ept, void *data, int len)
+{
+ struct glink_channel *channel = to_glink_channel(ept);
+
+ return __glink_rpm_send(channel, data, len, false);
+}
+
+/*
+ * Finds the device_node for the glink child interested in this channel.
+ */
+static struct device_node *glink_rpm_match_channel(struct device_node *node,
+ const char *channel)
+{
+ struct device_node *child;
+ const char *name;
+ const char *key;
+ int ret;
+
+ for_each_available_child_of_node(node, child) {
+ key = "qcom,glink-channels";
+ ret = of_property_read_string(child, key, &name);
+ if (ret)
+ continue;
+
+ if (strcmp(name, channel) == 0)
+ return child;
+ }
+
+ return NULL;
+}
+
+static const struct rpmsg_device_ops glink_device_ops = {
+ .create_ept = glink_rpm_create_ept,
+};
+
+static const struct rpmsg_endpoint_ops glink_endpoint_ops = {
+ .destroy_ept = glink_rpm_destroy_ept,
+ .send = glink_rpm_send,
+ .trysend = glink_rpm_trysend,
+};
+
+static void glink_rpm_rpdev_release(struct device *dev)
+{
+ struct rpmsg_device *rpdev = to_rpmsg_device(dev);
+ struct glink_channel *channel = to_glink_channel(rpdev->ept);
+
+ channel->rpdev = NULL;
+ kfree(rpdev);
+}
+
+static int glink_rpm_rx_open(struct glink_rpm *glink, unsigned int rcid,
+ char *name)
+{
+ struct glink_channel *channel;
+ struct rpmsg_device *rpdev;
+ bool create_device = false;
+ int lcid;
+ int ret;
+
+ idr_for_each_entry(&glink->lcids, channel, lcid) {
+ if (!strcmp(channel->name, name))
+ break;
+ }
+
+ if (!channel) {
+ channel = glink_rpm_alloc_channel(glink, name);
+ if (IS_ERR(channel))
+ return PTR_ERR(channel);
+
+ /* The opening dance was initiated by the remote */
+ create_device = true;
+ }
+
+ mutex_lock(&glink->idr_lock);
+ ret = idr_alloc(&glink->rcids, channel, rcid, rcid + 1, GFP_KERNEL);
+ if (ret < 0) {
+ dev_err(glink->dev, "Unable to insert channel into rcid list\n");
+ mutex_unlock(&glink->idr_lock);
+ goto free_channel;
+ }
+ channel->rcid = ret;
+ mutex_unlock(&glink->idr_lock);
+
+ complete(&channel->open_req);
+
+ if (create_device) {
+ rpdev = kzalloc(sizeof(*rpdev), GFP_KERNEL);
+ if (!rpdev) {
+ ret = -ENOMEM;
+ goto rcid_remove;
+ }
+
+ rpdev->ept = &channel->ept;
+ strncpy(rpdev->id.name, name, RPMSG_NAME_SIZE);
+ rpdev->src = RPMSG_ADDR_ANY;
+ rpdev->dst = RPMSG_ADDR_ANY;
+ rpdev->ops = &glink_device_ops;
+
+ rpdev->dev.of_node = glink_rpm_match_channel(glink->dev->of_node, name);
+ rpdev->dev.parent = glink->dev;
+ rpdev->dev.release = glink_rpm_rpdev_release;
+
+ ret = rpmsg_register_device(rpdev);
+ if (ret)
+ goto free_rpdev;
+
+ channel->rpdev = rpdev;
+ }
+
+ return 0;
+
+free_rpdev:
+ kfree(rpdev);
+rcid_remove:
+ mutex_lock(&glink->idr_lock);
+ idr_remove(&glink->rcids, channel->rcid);
+ channel->rcid = 0;
+ mutex_unlock(&glink->idr_lock);
+free_channel:
+ /* Release the reference, iff we took it */
+ if (create_device)
+ kref_put(&channel->refcount, glink_rpm_channel_release);
+
+ return ret;
+}
+
+static void glink_rpm_rx_close(struct glink_rpm *glink, unsigned int rcid)
+{
+ struct rpmsg_channel_info chinfo;
+ struct glink_channel *channel;
+
+ channel = idr_find(&glink->rcids, rcid);
+ if (WARN(!channel, "close request on unknown channel\n"))
+ return;
+
+ if (channel->rpdev) {
+ strncpy(chinfo.name, channel->name, sizeof(chinfo.name));
+ chinfo.src = RPMSG_ADDR_ANY;
+ chinfo.dst = RPMSG_ADDR_ANY;
+
+ rpmsg_unregister_device(glink->dev, &chinfo);
+ }
+
+ glink_rpm_send_close_ack(glink, channel->rcid);
+
+ mutex_lock(&glink->idr_lock);
+ idr_remove(&glink->rcids, channel->rcid);
+ channel->rcid = 0;
+ mutex_unlock(&glink->idr_lock);
+
+ kref_put(&channel->refcount, glink_rpm_channel_release);
+}
+
+static void glink_rpm_rx_close_ack(struct glink_rpm *glink, unsigned int lcid)
+{
+ struct glink_channel *channel;
+
+ channel = idr_find(&glink->lcids, lcid);
+ if (WARN(!channel, "close ack on unknown channel\n"))
+ return;
+
+ mutex_lock(&glink->idr_lock);
+ idr_remove(&glink->lcids, channel->lcid);
+ channel->lcid = 0;
+ mutex_unlock(&glink->idr_lock);
+
+ kref_put(&channel->refcount, glink_rpm_channel_release);
+}
+
+static void glink_rpm_work(struct work_struct *work)
+{
+ struct glink_rpm *glink = container_of(work, struct glink_rpm, rx_work);
+ struct glink_defer_cmd *dcmd;
+ struct glink_msg *msg;
+ unsigned long flags;
+ unsigned int param1;
+ unsigned int param2;
+ unsigned int cmd;
+
+ for (;;) {
+ spin_lock_irqsave(&glink->rx_lock, flags);
+ if (list_empty(&glink->rx_queue)) {
+ spin_unlock_irqrestore(&glink->rx_lock, flags);
+ break;
+ }
+ dcmd = list_first_entry(&glink->rx_queue, struct glink_defer_cmd, node);
+ list_del(&dcmd->node);
+ spin_unlock_irqrestore(&glink->rx_lock, flags);
+
+ msg = &dcmd->msg;
+ cmd = le16_to_cpu(msg->cmd);
+ param1 = le16_to_cpu(msg->param1);
+ param2 = le32_to_cpu(msg->param2);
+
+ switch (cmd) {
+ case RPM_CMD_VERSION:
+ glink_rpm_send_version_ack(glink);
+ break;
+ case RPM_CMD_VERSION_ACK:
+ break;
+ case RPM_CMD_OPEN:
+ glink_rpm_rx_open(glink, param1, msg->data);
+ break;
+ case RPM_CMD_CLOSE:
+ glink_rpm_rx_close(glink, param1);
+ break;
+ case RPM_CMD_CLOSE_ACK:
+ glink_rpm_rx_close_ack(glink, param1);
+ break;
+ default:
+ WARN(1, "Unknown defer object %d\n", cmd);
+ break;
+ }
+
+ kfree(dcmd);
+ }
+}
+
+static int glink_rpm_parse_toc(struct device *dev,
+ void __iomem *msg_ram,
+ size_t msg_ram_size,
+ struct glink_rpm_pipe *rx,
+ struct glink_rpm_pipe *tx)
+{
+ struct rpm_toc *toc;
+ int num_entries;
+ unsigned int id;
+ size_t offset;
+ size_t size;
+ void *buf;
+ int i;
+
+ buf = kzalloc(RPM_TOC_SIZE, GFP_KERNEL);
+ if (!buf)
+ return -ENOMEM;
+
+ __ioread32_copy(buf, msg_ram + msg_ram_size - RPM_TOC_SIZE,
+ RPM_TOC_SIZE / sizeof(u32));
+
+ toc = buf;
+
+ if (le32_to_cpu(toc->magic) != RPM_TOC_MAGIC) {
+ dev_err(dev, "RPM TOC has invalid magic\n");
+ goto err_inval;
+ }
+
+ num_entries = le32_to_cpu(toc->count);
+ if (num_entries > RPM_TOC_MAX_ENTRIES) {
+ dev_err(dev, "Invalid number of toc entries\n");
+ goto err_inval;
+ }
+
+ for (i = 0; i < num_entries; i++) {
+ id = le32_to_cpu(toc->entries[i].id);
+ offset = le32_to_cpu(toc->entries[i].offset);
+ size = le32_to_cpu(toc->entries[i].size);
+
+ if (offset > msg_ram_size || offset + size > msg_ram_size) {
+ dev_err(dev, "TOC entry with invalid size\n");
+ continue;
+ }
+
+ switch (id) {
+ case RPM_RX_FIFO_ID:
+ rx->length = size;
+
+ rx->tail = msg_ram + offset;
+ rx->head = msg_ram + offset + sizeof(u32);
+ rx->fifo = msg_ram + offset + 2 * sizeof(u32);
+ break;
+ case RPM_TX_FIFO_ID:
+ tx->length = size;
+
+ tx->tail = msg_ram + offset;
+ tx->head = msg_ram + offset + sizeof(u32);
+ tx->fifo = msg_ram + offset + 2 * sizeof(u32);
+ break;
+ }
+ }
+
+ if (!rx->fifo || !tx->fifo) {
+ dev_err(dev, "Unable to find rx and tx descriptors\n");
+ goto err_inval;
+ }
+
+ kfree(buf);
+ return 0;
+
+err_inval:
+ kfree(buf);
+ return -EINVAL;
+}
+
+static int glink_rpm_probe(struct platform_device *pdev)
+{
+ struct of_phandle_args args;
+ struct glink_rpm *glink;
+ struct device_node *np;
+ void __iomem *msg_ram;
+ size_t msg_ram_size;
+ struct device *dev = &pdev->dev;
+ struct resource r;
+ int irq;
+ int ret;
+
+ glink = devm_kzalloc(dev, sizeof(*glink), GFP_KERNEL);
+ if (!glink)
+ return -ENOMEM;
+
+ glink->dev = dev;
+
+ mutex_init(&glink->tx_lock);
+ spin_lock_init(&glink->rx_lock);
+ INIT_LIST_HEAD(&glink->rx_queue);
+ INIT_WORK(&glink->rx_work, glink_rpm_work);
+
+ mutex_init(&glink->idr_lock);
+ idr_init(&glink->lcids);
+ idr_init(&glink->rcids);
+
+ ret = of_parse_phandle_with_fixed_args(dev->of_node,
+ "qcom,ipc", 2, 0,
+ &args);
+ if (ret < 0) {
+ dev_err(dev, "Failed to parse qcom,ipc\n");
+ return ret;
+ }
+
+ glink->ipc_offset = args.args[0];
+ glink->ipc_bit = args.args[1];
+
+ glink->ipc_regmap = syscon_node_to_regmap(args.np);
+ of_node_put(args.np);
+ if (IS_ERR(glink->ipc_regmap))
+ return PTR_ERR(glink->ipc_regmap);
+
+ np = of_parse_phandle(dev->of_node, "qcom,rpm-msg-ram", 0);
+ ret = of_address_to_resource(np, 0, &r);
+ of_node_put(np);
+ if (ret)
+ return ret;
+
+ msg_ram = devm_ioremap(dev, r.start, resource_size(&r));
+ msg_ram_size = resource_size(&r);
+ if (!msg_ram)
+ return -ENOMEM;
+
+ ret = glink_rpm_parse_toc(dev, msg_ram, msg_ram_size,
+ &glink->rx_pipe, &glink->tx_pipe);
+ if (ret)
+ return ret;
+
+ writel(0, glink->tx_pipe.head);
+ writel(0, glink->rx_pipe.tail);
+
+ irq = platform_get_irq(pdev, 0);
+ ret = devm_request_irq(dev, irq,
+ glink_rpm_intr,
+ IRQF_NO_SUSPEND | IRQF_SHARED,
+ "glink-rpm", glink);
+ if (ret) {
+ dev_err(dev, "Failed to request IRQ\n");
+ return ret;
+ }
+
+ glink->irq = irq;
+
+ ret = glink_rpm_send_version(glink);
+ if (ret)
+ return ret;
+
+ platform_set_drvdata(pdev, glink);
+
+ return 0;
+}
+
+static int glink_rpm_remove_device(struct device *dev, void *data)
+{
+ device_unregister(dev);
+
+ return 0;
+}
+
+static int glink_rpm_remove(struct platform_device *pdev)
+{
+ struct glink_rpm *glink = platform_get_drvdata(pdev);
+ struct glink_channel *channel;
+ int cid;
+ int ret;
+
+ disable_irq(glink->irq);
+ cancel_work_sync(&glink->rx_work);
+
+ ret = device_for_each_child(glink->dev, NULL, glink_rpm_remove_device);
+ if (ret)
+ dev_warn(glink->dev, "Can't remove GLINK devices: %d\n", ret);
+
+ /* Release any defunct local channels, waiting for close-ack */
+ idr_for_each_entry(&glink->lcids, channel, cid)
+ kref_put(&channel->refcount, glink_rpm_channel_release);
+
+ idr_destroy(&glink->lcids);
+ idr_destroy(&glink->rcids);
+
+ return 0;
+}
+
+static const struct of_device_id glink_rpm_of_match[] = {
+ { .compatible = "qcom,glink-rpm" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, glink_rpm_of_match);
+
+static struct platform_driver glink_rpm_driver = {
+ .probe = glink_rpm_probe,
+ .remove = glink_rpm_remove,
+ .driver = {
+ .name = "qcom_glink_rpm",
+ .of_match_table = glink_rpm_of_match,
+ },
+};
+
+static int __init glink_rpm_init(void)
+{
+ return platform_driver_register(&glink_rpm_driver);
+}
+subsys_initcall(glink_rpm_init);
+
+static void __exit glink_rpm_exit(void)
+{
+ platform_driver_unregister(&glink_rpm_driver);
+}
+module_exit(glink_rpm_exit);
+
+MODULE_AUTHOR("Bjorn Andersson <bjorn.andersson@linaro.org>");
+MODULE_DESCRIPTION("Qualcomm GLINK RPM driver");
+MODULE_LICENSE("GPL v2");
--
2.12.0
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