diff options
Diffstat (limited to 'drivers/mfd/dln2.c')
| -rw-r--r-- | drivers/mfd/dln2.c | 781 |
1 files changed, 781 insertions, 0 deletions
diff --git a/drivers/mfd/dln2.c b/drivers/mfd/dln2.c new file mode 100644 index 000000000000..6d49685d4ee4 --- /dev/null +++ b/drivers/mfd/dln2.c @@ -0,0 +1,781 @@ +/* + * Driver for the Diolan DLN-2 USB adapter + * + * Copyright (c) 2014 Intel Corporation + * + * Derived from: + * i2c-diolan-u2c.c + * Copyright (c) 2010-2011 Ericsson AB + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation, version 2. + */ + +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/types.h> +#include <linux/slab.h> +#include <linux/usb.h> +#include <linux/i2c.h> +#include <linux/mutex.h> +#include <linux/platform_device.h> +#include <linux/mfd/core.h> +#include <linux/mfd/dln2.h> +#include <linux/rculist.h> + +struct dln2_header { + __le16 size; + __le16 id; + __le16 echo; + __le16 handle; +}; + +struct dln2_response { + struct dln2_header hdr; + __le16 result; +}; + +#define DLN2_GENERIC_MODULE_ID 0x00 +#define DLN2_GENERIC_CMD(cmd) DLN2_CMD(cmd, DLN2_GENERIC_MODULE_ID) +#define CMD_GET_DEVICE_VER DLN2_GENERIC_CMD(0x30) +#define CMD_GET_DEVICE_SN DLN2_GENERIC_CMD(0x31) + +#define DLN2_HW_ID 0x200 +#define DLN2_USB_TIMEOUT 200 /* in ms */ +#define DLN2_MAX_RX_SLOTS 16 +#define DLN2_MAX_URBS 16 +#define DLN2_RX_BUF_SIZE 512 + +enum dln2_handle { + DLN2_HANDLE_EVENT = 0, /* don't change, hardware defined */ + DLN2_HANDLE_CTRL, + DLN2_HANDLE_GPIO, + DLN2_HANDLE_I2C, + DLN2_HANDLE_SPI, + DLN2_HANDLES +}; + +/* + * Receive context used between the receive demultiplexer and the transfer + * routine. While sending a request the transfer routine will look for a free + * receive context and use it to wait for a response and to receive the URB and + * thus the response data. + */ +struct dln2_rx_context { + /* completion used to wait for a response */ + struct completion done; + + /* if non-NULL the URB contains the response */ + struct urb *urb; + + /* if true then this context is used to wait for a response */ + bool in_use; +}; + +/* + * Receive contexts for a particular DLN2 module (i2c, gpio, etc.). We use the + * handle header field to identify the module in dln2_dev.mod_rx_slots and then + * the echo header field to index the slots field and find the receive context + * for a particular request. + */ +struct dln2_mod_rx_slots { + /* RX slots bitmap */ + DECLARE_BITMAP(bmap, DLN2_MAX_RX_SLOTS); + + /* used to wait for a free RX slot */ + wait_queue_head_t wq; + + /* used to wait for an RX operation to complete */ + struct dln2_rx_context slots[DLN2_MAX_RX_SLOTS]; + + /* avoid races between alloc/free_rx_slot and dln2_rx_transfer */ + spinlock_t lock; +}; + +struct dln2_dev { + struct usb_device *usb_dev; + struct usb_interface *interface; + u8 ep_in; + u8 ep_out; + + struct urb *rx_urb[DLN2_MAX_URBS]; + void *rx_buf[DLN2_MAX_URBS]; + + struct dln2_mod_rx_slots mod_rx_slots[DLN2_HANDLES]; + + struct list_head event_cb_list; + spinlock_t event_cb_lock; + + bool disconnect; + int active_transfers; + wait_queue_head_t disconnect_wq; + spinlock_t disconnect_lock; +}; + +struct dln2_event_cb_entry { + struct list_head list; + u16 id; + struct platform_device *pdev; + dln2_event_cb_t callback; +}; + +int dln2_register_event_cb(struct platform_device *pdev, u16 id, + dln2_event_cb_t event_cb) +{ + struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent); + struct dln2_event_cb_entry *i, *entry; + unsigned long flags; + int ret = 0; + + entry = kzalloc(sizeof(*entry), GFP_KERNEL); + if (!entry) + return -ENOMEM; + + entry->id = id; + entry->callback = event_cb; + entry->pdev = pdev; + + spin_lock_irqsave(&dln2->event_cb_lock, flags); + + list_for_each_entry(i, &dln2->event_cb_list, list) { + if (i->id == id) { + ret = -EBUSY; + break; + } + } + + if (!ret) + list_add_rcu(&entry->list, &dln2->event_cb_list); + + spin_unlock_irqrestore(&dln2->event_cb_lock, flags); + + if (ret) + kfree(entry); + + return ret; +} +EXPORT_SYMBOL(dln2_register_event_cb); + +void dln2_unregister_event_cb(struct platform_device *pdev, u16 id) +{ + struct dln2_dev *dln2 = dev_get_drvdata(pdev->dev.parent); + struct dln2_event_cb_entry *i; + unsigned long flags; + bool found = false; + + spin_lock_irqsave(&dln2->event_cb_lock, flags); + + list_for_each_entry(i, &dln2->event_cb_list, list) { + if (i->id == id) { + list_del_rcu(&i->list); + found = true; + break; + } + } + + spin_unlock_irqrestore(&dln2->event_cb_lock, flags); + + if (found) { + synchronize_rcu(); + kfree(i); + } +} +EXPORT_SYMBOL(dln2_unregister_event_cb); + +/* + * Returns true if a valid transfer slot is found. In this case the URB must not + * be resubmitted immediately in dln2_rx as we need the data when dln2_transfer + * is woke up. It will be resubmitted there. + */ +static bool dln2_transfer_complete(struct dln2_dev *dln2, struct urb *urb, + u16 handle, u16 rx_slot) +{ + struct device *dev = &dln2->interface->dev; + struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle]; + struct dln2_rx_context *rxc; + bool valid_slot = false; + + if (rx_slot >= DLN2_MAX_RX_SLOTS) + goto out; + + rxc = &rxs->slots[rx_slot]; + + /* + * No need to disable interrupts as this lock is not taken in interrupt + * context elsewhere in this driver. This function (or its callers) are + * also not exported to other modules. + */ + spin_lock(&rxs->lock); + if (rxc->in_use && !rxc->urb) { + rxc->urb = urb; + complete(&rxc->done); + valid_slot = true; + } + spin_unlock(&rxs->lock); + +out: + if (!valid_slot) + dev_warn(dev, "bad/late response %d/%d\n", handle, rx_slot); + + return valid_slot; +} + +static void dln2_run_event_callbacks(struct dln2_dev *dln2, u16 id, u16 echo, + void *data, int len) +{ + struct dln2_event_cb_entry *i; + + rcu_read_lock(); + + list_for_each_entry_rcu(i, &dln2->event_cb_list, list) { + if (i->id == id) { + i->callback(i->pdev, echo, data, len); + break; + } + } + + rcu_read_unlock(); +} + +static void dln2_rx(struct urb *urb) +{ + struct dln2_dev *dln2 = urb->context; + struct dln2_header *hdr = urb->transfer_buffer; + struct device *dev = &dln2->interface->dev; + u16 id, echo, handle, size; + u8 *data; + int len; + int err; + + switch (urb->status) { + case 0: + /* success */ + break; + case -ECONNRESET: + case -ENOENT: + case -ESHUTDOWN: + case -EPIPE: + /* this urb is terminated, clean up */ + dev_dbg(dev, "urb shutting down with status %d\n", urb->status); + return; + default: + dev_dbg(dev, "nonzero urb status received %d\n", urb->status); + goto out; + } + + if (urb->actual_length < sizeof(struct dln2_header)) { + dev_err(dev, "short response: %d\n", urb->actual_length); + goto out; + } + + handle = le16_to_cpu(hdr->handle); + id = le16_to_cpu(hdr->id); + echo = le16_to_cpu(hdr->echo); + size = le16_to_cpu(hdr->size); + + if (size != urb->actual_length) { + dev_err(dev, "size mismatch: handle %x cmd %x echo %x size %d actual %d\n", + handle, id, echo, size, urb->actual_length); + goto out; + } + + if (handle >= DLN2_HANDLES) { + dev_warn(dev, "invalid handle %d\n", handle); + goto out; + } + + data = urb->transfer_buffer + sizeof(struct dln2_header); + len = urb->actual_length - sizeof(struct dln2_header); + + if (handle == DLN2_HANDLE_EVENT) { + dln2_run_event_callbacks(dln2, id, echo, data, len); + } else { + /* URB will be re-submitted in _dln2_transfer (free_rx_slot) */ + if (dln2_transfer_complete(dln2, urb, handle, echo)) + return; + } + +out: + err = usb_submit_urb(urb, GFP_ATOMIC); + if (err < 0) + dev_err(dev, "failed to resubmit RX URB: %d\n", err); +} + +static void *dln2_prep_buf(u16 handle, u16 cmd, u16 echo, const void *obuf, + int *obuf_len, gfp_t gfp) +{ + int len; + void *buf; + struct dln2_header *hdr; + + len = *obuf_len + sizeof(*hdr); + buf = kmalloc(len, gfp); + if (!buf) + return NULL; + + hdr = (struct dln2_header *)buf; + hdr->id = cpu_to_le16(cmd); + hdr->size = cpu_to_le16(len); + hdr->echo = cpu_to_le16(echo); + hdr->handle = cpu_to_le16(handle); + + memcpy(buf + sizeof(*hdr), obuf, *obuf_len); + + *obuf_len = len; + + return buf; +} + +static int dln2_send_wait(struct dln2_dev *dln2, u16 handle, u16 cmd, u16 echo, + const void *obuf, int obuf_len) +{ + int ret = 0; + int len = obuf_len; + void *buf; + int actual; + + buf = dln2_prep_buf(handle, cmd, echo, obuf, &len, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + ret = usb_bulk_msg(dln2->usb_dev, + usb_sndbulkpipe(dln2->usb_dev, dln2->ep_out), + buf, len, &actual, DLN2_USB_TIMEOUT); + + kfree(buf); + + return ret; +} + +static bool find_free_slot(struct dln2_dev *dln2, u16 handle, int *slot) +{ + struct dln2_mod_rx_slots *rxs; + unsigned long flags; + + if (dln2->disconnect) { + *slot = -ENODEV; + return true; + } + + rxs = &dln2->mod_rx_slots[handle]; + + spin_lock_irqsave(&rxs->lock, flags); + + *slot = find_first_zero_bit(rxs->bmap, DLN2_MAX_RX_SLOTS); + + if (*slot < DLN2_MAX_RX_SLOTS) { + struct dln2_rx_context *rxc = &rxs->slots[*slot]; + + set_bit(*slot, rxs->bmap); + rxc->in_use = true; + } + + spin_unlock_irqrestore(&rxs->lock, flags); + + return *slot < DLN2_MAX_RX_SLOTS; +} + +static int alloc_rx_slot(struct dln2_dev *dln2, u16 handle) +{ + int ret; + int slot; + + /* + * No need to timeout here, the wait is bounded by the timeout in + * _dln2_transfer. + */ + ret = wait_event_interruptible(dln2->mod_rx_slots[handle].wq, + find_free_slot(dln2, handle, &slot)); + if (ret < 0) + return ret; + + return slot; +} + +static void free_rx_slot(struct dln2_dev *dln2, u16 handle, int slot) +{ + struct dln2_mod_rx_slots *rxs; + struct urb *urb = NULL; + unsigned long flags; + struct dln2_rx_context *rxc; + + rxs = &dln2->mod_rx_slots[handle]; + + spin_lock_irqsave(&rxs->lock, flags); + + clear_bit(slot, rxs->bmap); + + rxc = &rxs->slots[slot]; + rxc->in_use = false; + urb = rxc->urb; + rxc->urb = NULL; + reinit_completion(&rxc->done); + + spin_unlock_irqrestore(&rxs->lock, flags); + + if (urb) { + int err; + struct device *dev = &dln2->interface->dev; + + err = usb_submit_urb(urb, GFP_KERNEL); + if (err < 0) + dev_err(dev, "failed to resubmit RX URB: %d\n", err); + } + + wake_up_interruptible(&rxs->wq); +} + +static int _dln2_transfer(struct dln2_dev *dln2, u16 handle, u16 cmd, + const void *obuf, unsigned obuf_len, + void *ibuf, unsigned *ibuf_len) +{ + int ret = 0; + int rx_slot; + struct dln2_response *rsp; + struct dln2_rx_context *rxc; + struct device *dev = &dln2->interface->dev; + const unsigned long timeout = DLN2_USB_TIMEOUT * HZ / 1000; + struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[handle]; + int size; + + spin_lock(&dln2->disconnect_lock); + if (!dln2->disconnect) + dln2->active_transfers++; + else + ret = -ENODEV; + spin_unlock(&dln2->disconnect_lock); + + if (ret) + return ret; + + rx_slot = alloc_rx_slot(dln2, handle); + if (rx_slot < 0) { + ret = rx_slot; + goto out_decr; + } + + ret = dln2_send_wait(dln2, handle, cmd, rx_slot, obuf, obuf_len); + if (ret < 0) { + dev_err(dev, "USB write failed: %d\n", ret); + goto out_free_rx_slot; + } + + rxc = &rxs->slots[rx_slot]; + + ret = wait_for_completion_interruptible_timeout(&rxc->done, timeout); + if (ret <= 0) { + if (!ret) + ret = -ETIMEDOUT; + goto out_free_rx_slot; + } else { + ret = 0; + } + + if (dln2->disconnect) { + ret = -ENODEV; + goto out_free_rx_slot; + } + + /* if we got here we know that the response header has been checked */ + rsp = rxc->urb->transfer_buffer; + size = le16_to_cpu(rsp->hdr.size); + + if (size < sizeof(*rsp)) { + ret = -EPROTO; + goto out_free_rx_slot; + } + + if (le16_to_cpu(rsp->result) > 0x80) { + dev_dbg(dev, "%d received response with error %d\n", + handle, le16_to_cpu(rsp->result)); + ret = -EREMOTEIO; + goto out_free_rx_slot; + } + + if (!ibuf) + goto out_free_rx_slot; + + if (*ibuf_len > size - sizeof(*rsp)) + *ibuf_len = size - sizeof(*rsp); + + memcpy(ibuf, rsp + 1, *ibuf_len); + +out_free_rx_slot: + free_rx_slot(dln2, handle, rx_slot); +out_decr: + spin_lock(&dln2->disconnect_lock); + dln2->active_transfers--; + spin_unlock(&dln2->disconnect_lock); + if (dln2->disconnect) + wake_up(&dln2->disconnect_wq); + + return ret; +} + +int dln2_transfer(struct platform_device *pdev, u16 cmd, + const void *obuf, unsigned obuf_len, + void *ibuf, unsigned *ibuf_len) +{ + struct dln2_platform_data *dln2_pdata; + struct dln2_dev *dln2; + u16 handle; + + dln2 = dev_get_drvdata(pdev->dev.parent); + dln2_pdata = dev_get_platdata(&pdev->dev); + handle = dln2_pdata->handle; + + return _dln2_transfer(dln2, handle, cmd, obuf, obuf_len, ibuf, + ibuf_len); +} +EXPORT_SYMBOL(dln2_transfer); + +static int dln2_check_hw(struct dln2_dev *dln2) +{ + int ret; + __le32 hw_type; + int len = sizeof(hw_type); + + ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_VER, + NULL, 0, &hw_type, &len); + if (ret < 0) + return ret; + if (len < sizeof(hw_type)) + return -EREMOTEIO; + + if (le32_to_cpu(hw_type) != DLN2_HW_ID) { + dev_err(&dln2->interface->dev, "Device ID 0x%x not supported\n", + le32_to_cpu(hw_type)); + return -ENODEV; + } + + return 0; +} + +static int dln2_print_serialno(struct dln2_dev *dln2) +{ + int ret; + __le32 serial_no; + int len = sizeof(serial_no); + struct device *dev = &dln2->interface->dev; + + ret = _dln2_transfer(dln2, DLN2_HANDLE_CTRL, CMD_GET_DEVICE_SN, NULL, 0, + &serial_no, &len); + if (ret < 0) + return ret; + if (len < sizeof(serial_no)) + return -EREMOTEIO; + + dev_info(dev, "Diolan DLN2 serial %u\n", le32_to_cpu(serial_no)); + + return 0; +} + +static int dln2_hw_init(struct dln2_dev *dln2) +{ + int ret; + + ret = dln2_check_hw(dln2); + if (ret < 0) + return ret; + + return dln2_print_serialno(dln2); +} + +static void dln2_free_rx_urbs(struct dln2_dev *dln2) +{ + int i; + + for (i = 0; i < DLN2_MAX_URBS; i++) { + usb_kill_urb(dln2->rx_urb[i]); + usb_free_urb(dln2->rx_urb[i]); + kfree(dln2->rx_buf[i]); + } +} + +static void dln2_free(struct dln2_dev *dln2) +{ + dln2_free_rx_urbs(dln2); + usb_put_dev(dln2->usb_dev); + kfree(dln2); +} + +static int dln2_setup_rx_urbs(struct dln2_dev *dln2, + struct usb_host_interface *hostif) +{ + int i; + int ret; + const int rx_max_size = DLN2_RX_BUF_SIZE; + struct device *dev = &dln2->interface->dev; + + for (i = 0; i < DLN2_MAX_URBS; i++) { + dln2->rx_buf[i] = kmalloc(rx_max_size, GFP_KERNEL); + if (!dln2->rx_buf[i]) + return -ENOMEM; + + dln2->rx_urb[i] = usb_alloc_urb(0, GFP_KERNEL); + if (!dln2->rx_urb[i]) + return -ENOMEM; + + usb_fill_bulk_urb(dln2->rx_urb[i], dln2->usb_dev, + usb_rcvbulkpipe(dln2->usb_dev, dln2->ep_in), + dln2->rx_buf[i], rx_max_size, dln2_rx, dln2); + + ret = usb_submit_urb(dln2->rx_urb[i], GFP_KERNEL); + if (ret < 0) { + dev_err(dev, "failed to submit RX URB: %d\n", ret); + return ret; + } + } + + return 0; +} + +static struct dln2_platform_data dln2_pdata_gpio = { + .handle = DLN2_HANDLE_GPIO, +}; + +/* Only one I2C port seems to be supported on current hardware */ +static struct dln2_platform_data dln2_pdata_i2c = { + .handle = DLN2_HANDLE_I2C, + .port = 0, +}; + +/* Only one SPI port supported */ +static struct dln2_platform_data dln2_pdata_spi = { + .handle = DLN2_HANDLE_SPI, + .port = 0, +}; + +static const struct mfd_cell dln2_devs[] = { + { + .name = "dln2-gpio", + .platform_data = &dln2_pdata_gpio, + .pdata_size = sizeof(struct dln2_platform_data), + }, + { + .name = "dln2-i2c", + .platform_data = &dln2_pdata_i2c, + .pdata_size = sizeof(struct dln2_platform_data), + }, + { + .name = "dln2-spi", + .platform_data = &dln2_pdata_spi, + .pdata_size = sizeof(struct dln2_platform_data), + }, +}; + +static void dln2_disconnect(struct usb_interface *interface) +{ + struct dln2_dev *dln2 = usb_get_intfdata(interface); + int i, j; + + /* don't allow starting new transfers */ + spin_lock(&dln2->disconnect_lock); + dln2->disconnect = true; + spin_unlock(&dln2->disconnect_lock); + + /* cancel in progress transfers */ + for (i = 0; i < DLN2_HANDLES; i++) { + struct dln2_mod_rx_slots *rxs = &dln2->mod_rx_slots[i]; + unsigned long flags; + + spin_lock_irqsave(&rxs->lock, flags); + + /* cancel all response waiters */ + for (j = 0; j < DLN2_MAX_RX_SLOTS; j++) { + struct dln2_rx_context *rxc = &rxs->slots[j]; + + if (rxc->in_use) + complete(&rxc->done); + } + + spin_unlock_irqrestore(&rxs->lock, flags); + } + + /* wait for transfers to end */ + wait_event(dln2->disconnect_wq, !dln2->active_transfers); + + mfd_remove_devices(&interface->dev); + + dln2_free(dln2); +} + +static int dln2_probe(struct usb_interface *interface, + const struct usb_device_id *usb_id) +{ + struct usb_host_interface *hostif = interface->cur_altsetting; + struct device *dev = &interface->dev; + struct dln2_dev *dln2; + int ret; + int i, j; + + if (hostif->desc.bInterfaceNumber != 0 || + hostif->desc.bNumEndpoints < 2) + return -ENODEV; + + dln2 = kzalloc(sizeof(*dln2), GFP_KERNEL); + if (!dln2) + return -ENOMEM; + + dln2->ep_out = hostif->endpoint[0].desc.bEndpointAddress; + dln2->ep_in = hostif->endpoint[1].desc.bEndpointAddress; + dln2->usb_dev = usb_get_dev(interface_to_usbdev(interface)); + dln2->interface = interface; + usb_set_intfdata(interface, dln2); + init_waitqueue_head(&dln2->disconnect_wq); + + for (i = 0; i < DLN2_HANDLES; i++) { + init_waitqueue_head(&dln2->mod_rx_slots[i].wq); + spin_lock_init(&dln2->mod_rx_slots[i].lock); + for (j = 0; j < DLN2_MAX_RX_SLOTS; j++) + init_completion(&dln2->mod_rx_slots[i].slots[j].done); + } + + spin_lock_init(&dln2->event_cb_lock); + spin_lock_init(&dln2->disconnect_lock); + INIT_LIST_HEAD(&dln2->event_cb_list); + + ret = dln2_setup_rx_urbs(dln2, hostif); + if (ret) + goto out_cleanup; + + ret = dln2_hw_init(dln2); + if (ret < 0) { + dev_err(dev, "failed to initialize hardware\n"); + goto out_cleanup; + } + + ret = mfd_add_hotplug_devices(dev, dln2_devs, ARRAY_SIZE(dln2_devs)); + if (ret != 0) { + dev_err(dev, "failed to add mfd devices to core\n"); + goto out_cleanup; + } + + return 0; + +out_cleanup: + dln2_free(dln2); + + return ret; +} + +static const struct usb_device_id dln2_table[] = { + { USB_DEVICE(0xa257, 0x2013) }, + { } +}; + +MODULE_DEVICE_TABLE(usb, dln2_table); + +static struct usb_driver dln2_driver = { + .name = "dln2", + .probe = dln2_probe, + .disconnect = dln2_disconnect, + .id_table = dln2_table, +}; + +module_usb_driver(dln2_driver); + +MODULE_AUTHOR("Octavian Purdila <octavian.purdila@intel.com>"); +MODULE_DESCRIPTION("Core driver for the Diolan DLN2 interface adapter"); +MODULE_LICENSE("GPL v2"); |