linux/drivers/mfd/dln2.c
Octavian Purdila 3daa122d6b mfd: dln2: Add suspend/resume functionality
Without suspend/resume functionality in the USB driver the USB core
will disconnect and reconnect the DLN2 port and because the GPIO
framework does not yet support removal of an in-use controller a
suspend/resume operation will result in a crash.

This patch provides suspend and resume functions for the DLN2 driver
so that the above scenario is avoided, if the host controller does not
drop VBUS during suspend, since in this case the device state is
preserved.

We chose not implemented reset_resume so that if the host controller
does drop VBUS the resume path will go through above the
disconnect/reconnect process since it is probably better to fix the
GPIO framework disconnect issue then to save and restore the device
state for every driver.

Signed-off-by: Octavian Purdila <octavian.purdila@intel.com>
Reviewed-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
2015-01-22 15:56:01 +00:00

833 lines
18 KiB
C

/*
* 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_free_urb(dln2->rx_urb[i]);
kfree(dln2->rx_buf[i]);
}
}
static void dln2_stop_rx_urbs(struct dln2_dev *dln2)
{
int i;
for (i = 0; i < DLN2_MAX_URBS; i++)
usb_kill_urb(dln2->rx_urb[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;
const int rx_max_size = DLN2_RX_BUF_SIZE;
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);
}
return 0;
}
static int dln2_start_rx_urbs(struct dln2_dev *dln2, gfp_t gfp)
{
struct device *dev = &dln2->interface->dev;
int ret;
int i;
for (i = 0; i < DLN2_MAX_URBS; i++) {
ret = usb_submit_urb(dln2->rx_urb[i], gfp);
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_stop(struct dln2_dev *dln2)
{
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);
dln2_stop_rx_urbs(dln2);
}
static void dln2_disconnect(struct usb_interface *interface)
{
struct dln2_dev *dln2 = usb_get_intfdata(interface);
dln2_stop(dln2);
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_free;
ret = dln2_start_rx_urbs(dln2, GFP_KERNEL);
if (ret)
goto out_stop_rx;
ret = dln2_hw_init(dln2);
if (ret < 0) {
dev_err(dev, "failed to initialize hardware\n");
goto out_stop_rx;
}
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_stop_rx;
}
return 0;
out_stop_rx:
dln2_stop_rx_urbs(dln2);
out_free:
dln2_free(dln2);
return ret;
}
static int dln2_suspend(struct usb_interface *iface, pm_message_t message)
{
struct dln2_dev *dln2 = usb_get_intfdata(iface);
dln2_stop(dln2);
return 0;
}
static int dln2_resume(struct usb_interface *iface)
{
struct dln2_dev *dln2 = usb_get_intfdata(iface);
dln2->disconnect = false;
return dln2_start_rx_urbs(dln2, GFP_NOIO);
}
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,
.suspend = dln2_suspend,
.resume = dln2_resume,
};
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");