From: "Edward A. James" <[email protected]> Add a miscdevice for the occ to allow userspace access through standard file operations.
Signed-off-by: Edward A. James <[email protected]> --- drivers/fsi/fsi-occ.c | 264 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 264 insertions(+) diff --git a/drivers/fsi/fsi-occ.c b/drivers/fsi/fsi-occ.c index 99dbfa3..1aeb67d 100644 --- a/drivers/fsi/fsi-occ.c +++ b/drivers/fsi/fsi-occ.c @@ -16,6 +16,7 @@ #include <linux/idr.h> #include <linux/kernel.h> #include <linux/list.h> +#include <linux/miscdevice.h> #include <linux/module.h> #include <linux/mutex.h> #include <linux/of.h> @@ -40,6 +41,7 @@ struct occ { struct device *sbefifo; char name[32]; int idx; + struct miscdevice mdev; struct list_head xfrs; spinlock_t list_lock; /* lock access to the xfrs list */ struct mutex occ_lock; /* lock access to the hardware */ @@ -113,6 +115,29 @@ struct occ_client { static DEFINE_IDA(occ_ida); +static int occ_enqueue_xfr(struct occ_xfr *xfr) +{ + int empty; + unsigned long flags; + struct occ_client *client = to_client(xfr); + struct occ *occ = client->occ; + + if (occ->cancel) + return -ENODEV; + + spin_lock_irqsave(&occ->list_lock, flags); + + empty = list_empty(&occ->xfrs); + list_add_tail(&xfr->link, &occ->xfrs); + + spin_unlock_irqrestore(&occ->list_lock, flags); + + if (empty) + queue_work(occ_wq, &occ->work); + + return 0; +} + static void occ_get_client(struct occ_client *client) { kref_get(&client->kref); @@ -131,6 +156,230 @@ static void occ_put_client(struct occ_client *client) kref_put(&client->kref, occ_client_release); } +static int occ_open(struct inode *inode, struct file *file) +{ + struct miscdevice *mdev = file->private_data; + struct occ *occ = to_occ(mdev); + struct occ_client *client = kzalloc(sizeof(*client), GFP_KERNEL); + + if (!client) + return -ENOMEM; + + client->occ = occ; + kref_init(&client->kref); + spin_lock_init(&client->lock); + init_waitqueue_head(&client->wait); + + if (file->f_flags & O_NONBLOCK) + set_bit(CLIENT_NONBLOCKING, &client->flags); + + file->private_data = client; + + return 0; +} + +static inline bool occ_read_ready(struct occ_xfr *xfr, struct occ *occ) +{ + return test_bit(XFR_COMPLETE, &xfr->flags) || + test_bit(XFR_CANCELED, &xfr->flags) || occ->cancel; +} + +static ssize_t occ_read(struct file *file, char __user *buf, size_t len, + loff_t *offset) +{ + int rc; + unsigned long flags; + size_t bytes; + struct occ_xfr *xfr; + struct occ *occ; + struct occ_client *client = file->private_data; + + if (!client) + return -ENODEV; + + if (len > OCC_SRAM_BYTES) + return -EINVAL; + + occ_get_client(client); + xfr = &client->xfr; + occ = client->occ; + + spin_lock_irqsave(&client->lock, flags); + + if (!test_bit(CLIENT_XFR_PENDING, &client->flags)) { + /* we just finished reading all data, return 0 */ + if (client->read_offset) { + rc = 0; + client->read_offset = 0; + } else { + rc = -ENOMSG; + } + + goto done; + } + + if (!test_bit(XFR_COMPLETE, &xfr->flags)) { + if (test_bit(CLIENT_NONBLOCKING, &client->flags)) { + rc = -EAGAIN; + goto done; + } + + spin_unlock_irqrestore(&client->lock, flags); + + rc = wait_event_interruptible(client->wait, + occ_read_ready(xfr, occ)); + + spin_lock_irqsave(&client->lock, flags); + + if (!test_bit(XFR_COMPLETE, &xfr->flags)) { + if (occ->cancel || test_bit(XFR_CANCELED, &xfr->flags)) + rc = -ENODEV; + else + rc = -EINTR; + + goto done; + } + } + + if (xfr->rc) { + rc = xfr->rc; + goto done; + } + + bytes = min(len, xfr->resp_data_length - client->read_offset); + if (copy_to_user(buf, &xfr->buf[client->read_offset], bytes)) { + rc = -EFAULT; + goto done; + } + + client->read_offset += bytes; + + /* xfr done */ + if (client->read_offset == xfr->resp_data_length) + clear_bit(CLIENT_XFR_PENDING, &client->flags); + + rc = bytes; + +done: + spin_unlock_irqrestore(&client->lock, flags); + occ_put_client(client); + return rc; +} + +static ssize_t occ_write(struct file *file, const char __user *buf, + size_t len, loff_t *offset) +{ + int rc; + unsigned long flags; + unsigned int i; + u16 data_length, checksum = 0; + struct occ_xfr *xfr; + struct occ_client *client = file->private_data; + + if (!client) + return -ENODEV; + + if (len > (OCC_CMD_DATA_BYTES + 3) || len < 3) + return -EINVAL; + + occ_get_client(client); + xfr = &client->xfr; + + spin_lock_irqsave(&client->lock, flags); + + if (test_bit(CLIENT_XFR_PENDING, &client->flags)) { + rc = -EBUSY; + goto done; + } + + memset(xfr, 0, sizeof(*xfr)); /* clear out the transfer */ + xfr->buf[0] = 1; /* occ sequence number */ + + /* + * Assume user data follows the occ command format. + * byte 0: command type + * bytes 1-2: data length (msb first) + * bytes 3-n: data + */ + if (copy_from_user(&xfr->buf[1], buf, len)) { + rc = -EFAULT; + goto done; + } + + data_length = (xfr->buf[2] << 8) + xfr->buf[3]; + if (data_length > OCC_CMD_DATA_BYTES) { + rc = -EINVAL; + goto done; + } + + for (i = 0; i < data_length + 4; ++i) + checksum += xfr->buf[i]; + + xfr->buf[data_length + 4] = checksum >> 8; + xfr->buf[data_length + 5] = checksum & 0xFF; + + xfr->cmd_data_length = data_length + 6; + client->read_offset = 0; + + rc = occ_enqueue_xfr(xfr); + if (rc) + goto done; + + set_bit(CLIENT_XFR_PENDING, &client->flags); + rc = len; + +done: + spin_unlock_irqrestore(&client->lock, flags); + occ_put_client(client); + return rc; +} + +static int occ_release(struct inode *inode, struct file *file) +{ + unsigned long flags; + struct occ *occ; + struct occ_xfr *xfr; + struct occ_client *client = file->private_data; + + if (!client) + return -ENODEV; + + xfr = &client->xfr; + occ = client->occ; + + spin_lock_irqsave(&client->lock, flags); + + set_bit(XFR_CANCELED, &xfr->flags); + if (!test_bit(CLIENT_XFR_PENDING, &client->flags)) + goto done; + + spin_lock(&occ->list_lock); + + if (!test_bit(XFR_IN_PROGRESS, &xfr->flags)) { + /* already deleted from list if complete */ + if (!test_bit(XFR_COMPLETE, &xfr->flags)) + list_del(&xfr->link); + } + + spin_unlock(&occ->list_lock); + + wake_up_all(&client->wait); + +done: + spin_unlock_irqrestore(&client->lock, flags); + + occ_put_client(client); + return 0; +} + +static const struct file_operations occ_fops = { + .owner = THIS_MODULE, + .open = occ_open, + .read = occ_read, + .write = occ_write, + .release = occ_release, +}; + static int occ_write_sbefifo(struct sbefifo_client *client, const char *buf, ssize_t len) { @@ -450,6 +699,19 @@ static int occ_probe(struct platform_device *pdev) occ->idx = ida_simple_get(&occ_ida, 1, INT_MAX, GFP_KERNEL); } + snprintf(occ->name, sizeof(occ->name), "occ%d", occ->idx); + occ->mdev.fops = &occ_fops; + occ->mdev.minor = MISC_DYNAMIC_MINOR; + occ->mdev.name = occ->name; + occ->mdev.parent = dev; + + rc = misc_register(&occ->mdev); + if (rc) { + dev_err(dev, "failed to register miscdevice: %d\n", rc); + ida_simple_remove(&occ_ida, occ->idx); + return rc; + } + platform_set_drvdata(pdev, occ); return 0; @@ -471,6 +733,8 @@ static int occ_remove(struct platform_device *pdev) } spin_unlock_irqrestore(&occ->list_lock, flags); + misc_deregister(&occ->mdev); + cancel_work_sync(&occ->work); ida_simple_remove(&occ_ida, occ->idx); -- 1.8.3.1
