[PATCH 2/2] i2c: i801: add support of Host Notify

Benjamin Tissoires
2015-06-23T18:58:19Z

The i801 chip can handle the Host Notify feature since ICH 3 as mentioned
in http://www.intel.com/content/dam/doc/datasheet/82801ca-io-controller-hub-3-datasheet.pdf

Implement .toggle_smbus_host_notify() and rely on .alert() to notify
the actual client that it has a notification.

With a T440s and a Synaptics touchpad that implements Host Notify, the
payload data is always 0x0000, so I am not sure if the device actually
sends the payload or if there is a problem regarding the implementation.

Part of this code is inspired by i2c-smbus.c.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>
---
drivers/i2c/busses/i2c-i801.c | 223 +++++++++++++++++++++++++++++++++---------
drivers/i2c/i2c-core.c | 34 +++++++
drivers/i2c/i2c-smbus.c | 17 +---
include/linux/i2c.h | 3 +
4 files changed, 217 insertions(+), 60 deletions(-)

diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c
index 5ecbb3f..22a3218 100644
--- a/drivers/i2c/busses/i2c-i801.c
+++ b/drivers/i2c/busses/i2c-i801.c
@@ -20,46 +20,46 @@
/*
* Supports the following Intel I/O Controller Hubs (ICH):
*
- * I/O Block I2C
- * region SMBus Block proc. block
- * Chip name PCI ID size PEC buffer call read
- * ---------------------------------------------------------------------------
- * 82801AA (ICH) 0x2413 16 no no no no
- * 82801AB (ICH0) 0x2423 16 no no no no
- * 82801BA (ICH2) 0x2443 16 no no no no
- * 82801CA (ICH3) 0x2483 32 soft no no no
- * 82801DB (ICH4) 0x24c3 32 hard yes no no
- * 82801E (ICH5) 0x24d3 32 hard yes yes yes
- * 6300ESB 0x25a4 32 hard yes yes yes
- * 82801F (ICH6) 0x266a 32 hard yes yes yes
- * 6310ESB/6320ESB 0x269b 32 hard yes yes yes
- * 82801G (ICH7) 0x27da 32 hard yes yes yes
- * 82801H (ICH8) 0x283e 32 hard yes yes yes
- * 82801I (ICH9) 0x2930 32 hard yes yes yes
- * EP80579 (Tolapai) 0x5032 32 hard yes yes yes
- * ICH10 0x3a30 32 hard yes yes yes
- * ICH10 0x3a60 32 hard yes yes yes
- * 5/3400 Series (PCH) 0x3b30 32 hard yes yes yes
- * 6 Series (PCH) 0x1c22 32 hard yes yes yes
- * Patsburg (PCH) 0x1d22 32 hard yes yes yes
- * Patsburg (PCH) IDF 0x1d70 32 hard yes yes yes
- * Patsburg (PCH) IDF 0x1d71 32 hard yes yes yes
- * Patsburg (PCH) IDF 0x1d72 32 hard yes yes yes
- * DH89xxCC (PCH) 0x2330 32 hard yes yes yes
- * Panther Point (PCH) 0x1e22 32 hard yes yes yes
- * Lynx Point (PCH) 0x8c22 32 hard yes yes yes
- * Lynx Point-LP (PCH) 0x9c22 32 hard yes yes yes
- * Avoton (SOC) 0x1f3c 32 hard yes yes yes
- * Wellsburg (PCH) 0x8d22 32 hard yes yes yes
- * Wellsburg (PCH) MS 0x8d7d 32 hard yes yes yes
- * Wellsburg (PCH) MS 0x8d7e 32 hard yes yes yes
- * Wellsburg (PCH) MS 0x8d7f 32 hard yes yes yes
- * Coleto Creek (PCH) 0x23b0 32 hard yes yes yes
- * Wildcat Point (PCH) 0x8ca2 32 hard yes yes yes
- * Wildcat Point-LP (PCH) 0x9ca2 32 hard yes yes yes
- * BayTrail (SOC) 0x0f12 32 hard yes yes yes
- * Sunrise Point-H (PCH) 0xa123 32 hard yes yes yes
- * Sunrise Point-LP (PCH) 0x9d23 32 hard yes yes yes
+ * I/O SMBus Block I2C
+ * region Slave Host SMBus Block proc. block
+ * Chip name PCI ID size mode notify PEC buffer call read
+ * ------------------------------------------------------------------------------------------
+ * 82801AA (ICH) 0x2413 16 no no no no no no
+ * 82801AB (ICH0) 0x2423 16 no no no no no no
+ * 82801BA (ICH2) 0x2443 16 yes no no no no no
+ * 82801CA (ICH3) 0x2483 32 yes yes soft no no no
+ * 82801DB (ICH4) 0x24c3 32 yes yes hard yes no no
+ * 82801E (ICH5) 0x24d3 32 yes yes hard yes yes yes
+ * 6300ESB 0x25a4 32 yes yes hard yes yes yes
+ * 82801F (ICH6) 0x266a 32 yes yes hard yes yes yes
+ * 6310ESB/6320ESB 0x269b 32 yes yes hard yes yes yes
+ * 82801G (ICH7) 0x27da 32 yes yes hard yes yes yes
+ * 82801H (ICH8) 0x283e 32 yes yes hard yes yes yes
+ * 82801I (ICH9) 0x2930 32 yes yes hard yes yes yes
+ * EP80579 (Tolapai) 0x5032 32 yes yes hard yes yes yes
+ * ICH10 0x3a30 32 yes yes hard yes yes yes
+ * ICH10 0x3a60 32 yes yes hard yes yes yes
+ * 5/3400 Series (PCH) 0x3b30 32 yes yes hard yes yes yes
+ * 6 Series (PCH) 0x1c22 32 yes yes hard yes yes yes
+ * Patsburg (PCH) 0x1d22 32 yes yes hard yes yes yes
+ * Patsburg (PCH) IDF 0x1d70 32 yes yes hard yes yes yes
+ * Patsburg (PCH) IDF 0x1d71 32 yes yes hard yes yes yes
+ * Patsburg (PCH) IDF 0x1d72 32 yes yes hard yes yes yes
+ * DH89xxCC (PCH) 0x2330 32 yes yes hard yes yes yes
+ * Panther Point (PCH) 0x1e22 32 yes yes hard yes yes yes
+ * Lynx Point (PCH) 0x8c22 32 yes yes hard yes yes yes
+ * Lynx Point-LP (PCH) 0x9c22 32 yes yes hard yes yes yes
+ * Avoton (SOC) 0x1f3c 32 yes yes hard yes yes yes
+ * Wellsburg (PCH) 0x8d22 32 yes yes hard yes yes yes
+ * Wellsburg (PCH) MS 0x8d7d 32 yes yes hard yes yes yes
+ * Wellsburg (PCH) MS 0x8d7e 32 yes yes hard yes yes yes
+ * Wellsburg (PCH) MS 0x8d7f 32 yes yes hard yes yes yes
+ * Coleto Creek (PCH) 0x23b0 32 yes yes hard yes yes yes
+ * Wildcat Point (PCH) 0x8ca2 32 yes yes hard yes yes yes
+ * Wildcat Point-LP (PCH) 0x9ca2 32 yes yes hard yes yes yes
+ * BayTrail (SOC) 0x0f12 32 yes yes hard yes yes yes
+ * Sunrise Point-H (PCH) 0xa123 32 yes yes hard yes yes yes
+ * Sunrise Point-LP (PCH) 0x9d23 32 yes yes hard yes yes yes
*
* Features supported by this driver:
* Software PEC no
@@ -68,6 +68,7 @@
* Block process call transaction no
* I2C block read transaction yes (doesn't use the block buffer)
* Slave mode no
+ * SMBus Host Notify yes
* Interrupt processing yes
*
* See the file Documentation/i2c/busses/i2c-i801 for details.
@@ -84,6 +85,7 @@
#include <linux/i2c.h>
#include <linux/acpi.h>
#include <linux/io.h>
+#include <linux/kfifo.h>
#include <linux/dmi.h>
#include <linux/slab.h>
#include <linux/wait.h>
@@ -107,6 +109,10 @@
#define SMBPEC(p) (8 + (p)->smba) /* ICH3 and later */
#define SMBAUXSTS(p) (12 + (p)->smba) /* ICH4 and later */
#define SMBAUXCTL(p) (13 + (p)->smba) /* ICH4 and later */
+#define SMBSLVSTS(p) (16 + (p)->smba) /* ICH3 and later */
+#define SMBSLVCMD(p) (17 + (p)->smba) /* ICH3 and later */
+#define SMBNTFDADD(p) (20 + (p)->smba) /* ICH3 and later */
+#define SMBNTFDDAT(p) (22 + (p)->smba) /* ICH3 and later */

/* PCI Address Constants */
#define SMBBAR 4
@@ -158,6 +164,12 @@
#define SMBHSTSTS_INTR 0x02
#define SMBHSTSTS_HOST_BUSY 0x01

+/* Host Notify Status registers bits */
+#define SMBSLVSTS_HST_NTFY_STS 1
+
+/* Host Notify Command registers bits */
+#define SMBSLVCMD_HST_NTFY_INTREN 0x01
+
#define STATUS_ERROR_FLAGS (SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \
SMBHSTSTS_DEV_ERR)

@@ -221,6 +233,17 @@ struct i801_priv {
const struct i801_mux_config *mux_drvdata;
struct platform_device *mux_pdev;
#endif
+
+ bool host_notify_requested;
+ struct work_struct host_notify;
+ struct kfifo host_notify_fifo;
+};
+
+#define SMBHSTNTFY_SIZE 8
+
+struct smbus_host_notify_data {
+ u8 addr;
+ u16 payload;
};

#define FEATURE_SMBUS_PEC (1 << 0)
@@ -228,6 +251,7 @@ struct i801_priv {
#define FEATURE_BLOCK_PROC (1 << 2)
#define FEATURE_I2C_BLOCK_READ (1 << 3)
#define FEATURE_IRQ (1 << 4)
+#define FEATURE_HOST_NOTIFY (1 << 5)
/* Not really a feature, but it's convenient to handle it as such */
#define FEATURE_IDF (1 << 15)

@@ -237,6 +261,7 @@ static const char *i801_feature_names[] = {
"Block process call",
"I2C block read",
"Interrupt",
+ "SMBus Host Notify",
};

static unsigned int disable_features;
@@ -245,7 +270,8 @@ MODULE_PARM_DESC(disable_features, "Disable selected driver features:\n"
"\t\t 0x01 disable SMBus PEC\n"
"\t\t 0x02 disable the block buffer\n"
"\t\t 0x08 disable the I2C block read functionality\n"
- "\t\t 0x10 don't use interrupts ");
+ "\t\t 0x10 don't use interrupts\n"
+ "\t\t 0x20 disable SMBus Host Notify ");

/* Make sure the SMBus host is ready to start transmitting.
Return 0 if it is, -EBUSY if it is not. */
@@ -479,8 +505,67 @@ static void i801_isr_byte_done(struct i801_priv *priv)
outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv));
}

+/* If this is the alerting device, notify its driver */
+static int i801_do_host_notify(struct device *dev, void *datap)
+{
+ struct i2c_client *client = i2c_verify_client(dev);
+ struct smbus_host_notify_data *data = datap;
+
+ if (!client || client->addr != data->addr)
+ return 0;
+ if (client->flags & I2C_CLIENT_TEN)
+ return 0;
+
+ if (i2c_alert(client, data->payload))
+ return 0;
+
+ /* Stop iterating after we find the device */
+ return -EBUSY;
+}
+
/*
- * There are two kinds of interrupts:
+ * The alert IRQ handler needs to hand work off to a task which can issue
+ * SMBus calls, because those sleeping calls can't be made in IRQ context.
+ */
+static void i801_host_notify(struct work_struct *work)
+{
+ struct i801_priv *priv;
+ struct smbus_host_notify_data data;
+ int count;
+
+ priv = container_of(work, struct i801_priv, host_notify);
+
+ count = kfifo_out(&priv->host_notify_fifo, &data,
+ sizeof(struct smbus_host_notify_data));
+
+ if (count != sizeof(struct smbus_host_notify_data)) {
+ dev_err(&priv->pci_dev->dev,
+ "Host Notification triggered without data\n");
+ return;
+ }
+
+ device_for_each_child(&priv->adapter.dev, &data, i801_do_host_notify);
+}
+
+static irqreturn_t i801_host_notify_isr(struct i801_priv *priv)
+{
+ struct smbus_host_notify_data data;
+
+ data.addr = inb_p(SMBNTFDADD(priv)) >> 1;
+ data.payload = inb_p(SMBNTFDDAT(priv)) |
+ (inb_p(SMBNTFDDAT(priv) + 1) << 8);
+
+ kfifo_in(&priv->host_notify_fifo, &data,
+ sizeof(struct smbus_host_notify_data));
+ schedule_work(&priv->host_notify);
+
+ /* clear Host Notify bit and return */
+ outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
+ return IRQ_HANDLED;
+}
+
+/*
+ * There are three kinds of interrupts:
*
* 1) i801 signals transaction completion with one of these interrupts:
* INTR - Success
@@ -492,6 +577,8 @@ static void i801_isr_byte_done(struct i801_priv *priv)
*
* 2) For byte-by-byte (I2C read/write) transactions, one BYTE_DONE interrupt
* occurs for each byte of a byte-by-byte to prepare the next byte.
+ *
+ * 3) Host Notify interrupts
*/
static irqreturn_t i801_isr(int irq, void *dev_id)
{
@@ -504,6 +591,12 @@ static irqreturn_t i801_isr(int irq, void *dev_id)
if (!(pcists & SMBPCISTS_INTS))
return IRQ_NONE;

+ if (priv->host_notify_requested) {
+ status = inb_p(SMBSLVSTS(priv));
+ if (status & SMBSLVSTS_HST_NTFY_STS)
+ return i801_host_notify_isr(priv);
+ }
+
status = inb_p(SMBHSTSTS(priv));
if (status & SMBHSTSTS_BYTE_DONE)
i801_isr_byte_done(priv);
@@ -801,12 +894,35 @@ static u32 i801_func(struct i2c_adapter *adapter)
I2C_FUNC_SMBUS_BLOCK_DATA | I2C_FUNC_SMBUS_WRITE_I2C_BLOCK |
((priv->features & FEATURE_SMBUS_PEC) ? I2C_FUNC_SMBUS_PEC : 0) |
((priv->features & FEATURE_I2C_BLOCK_READ) ?
- I2C_FUNC_SMBUS_READ_I2C_BLOCK : 0);
+ I2C_FUNC_SMBUS_READ_I2C_BLOCK : 0) |
+ ((priv->features & FEATURE_HOST_NOTIFY) ?
+ I2C_FUNC_SMBUS_HOST_NOTIFY : 0);
+}
+
+static int i801_toggle_host_ntfy(struct i2c_adapter *adapter, bool state)
+{
+ struct i801_priv *priv = i2c_get_adapdata(adapter);
+
+ if (!(priv->features & FEATURE_HOST_NOTIFY))
+ return -EOPNOTSUPP;
+
+ if (state) {
+ outb_p(SMBSLVCMD_HST_NTFY_INTREN, SMBSLVCMD(priv));
+ /* clear Host Notify bit to allow a new notification */
+ outb_p(SMBSLVSTS_HST_NTFY_STS, SMBSLVSTS(priv));
+ } else {
+ outb_p(0, SMBSLVCMD(priv));
+ }
+
+ priv->host_notify_requested = state;
+
+ return 0;
}

static const struct i2c_algorithm smbus_algorithm = {
- .smbus_xfer = i801_access,
- .functionality = i801_func,
+ .smbus_xfer = i801_access,
+ .functionality = i801_func,
+ .toggle_smbus_host_notify = i801_toggle_host_ntfy,
};

static const struct pci_device_id i801_ids[] = {
@@ -1166,6 +1282,7 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
priv->features |= FEATURE_BLOCK_BUFFER;
/* fall through */
case PCI_DEVICE_ID_INTEL_82801CA_3:
+ priv->features |= FEATURE_HOST_NOTIFY;
case PCI_DEVICE_ID_INTEL_82801BA_2:
case PCI_DEVICE_ID_INTEL_82801AB_3:
case PCI_DEVICE_ID_INTEL_82801AA_3:
@@ -1250,6 +1367,15 @@ static int i801_probe(struct pci_dev *dev, const struct pci_device_id *id)
}
}

+ INIT_WORK(&priv->host_notify, i801_host_notify);
+ if (kfifo_alloc(&priv->host_notify_fifo,
+ SMBHSTNTFY_SIZE * sizeof(struct smbus_host_notify_data),
+ GFP_KERNEL)) {
+ dev_err(&dev->dev,
+ "%s:failed allocating host_notify_fifo\n", __func__);
+ return -ENOMEM;
+ }
+
if (priv->features & FEATURE_IRQ) {
init_waitqueue_head(&priv->waitq);

@@ -1292,6 +1418,9 @@ static void i801_remove(struct pci_dev *dev)
{
struct i801_priv *priv = pci_get_drvdata(dev);

+ cancel_work_sync(&priv->host_notify);
+ kfifo_free(&priv->host_notify_fifo);
+
i801_del_mux(priv);
i2c_del_adapter(&priv->adapter);
pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg);
@@ -1315,8 +1444,12 @@ static int i801_suspend(struct pci_dev *dev, pm_message_t mesg)

static int i801_resume(struct pci_dev *dev)
{
+ struct i801_priv *priv = pci_get_drvdata(dev);
+
pci_set_power_state(dev, PCI_D0);
pci_restore_state(dev);
+ if (priv->host_notify_requested)
+ i801_toggle_host_ntfy(&priv->adapter, true);
return 0;
}
#else
diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index eaaf5b0..87904ec 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -2145,6 +2145,40 @@ int i2c_master_send(const struct i2c_client *client, const char *buf, int count)
EXPORT_SYMBOL(i2c_master_send);

/**
+ * i2c_alert - call an alert for the given i2c_client.
+ * @client: Handle to slave device
+ * @data: Payload data that will be sent to the slave
+ *
+ * Returns negative errno, or 0.
+ */
+int i2c_alert(struct i2c_client *client, unsigned int data)
+{
+ struct i2c_driver *driver;
+
+ if (!client)
+ return -EINVAL;
+
+ /*
+ * Drivers should either disable alerts, or provide at least
+ * a minimal handler. Lock so the driver won't change.
+ */
+ device_lock(&client->adapter->dev);
+ if (client->dev.driver) {
+ driver = to_i2c_driver(client->dev.driver);
+ if (driver->alert)
+ driver->alert(client, data);
+ else
+ dev_warn(&client->dev, "no driver alert()!\n");
+ } else
+ dev_dbg(&client->dev, "alert with no driver\n");
+ device_unlock(&client->adapter->dev);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(i2c_alert);
+
+
+/**
* i2c_master_recv - issue a single I2C message in master receive mode
* @client: Handle to slave device
* @buf: Where to store data read from slave
diff --git a/drivers/i2c/i2c-smbus.c b/drivers/i2c/i2c-smbus.c
index 9ebf9cb..26439a8 100644
--- a/drivers/i2c/i2c-smbus.c
+++ b/drivers/i2c/i2c-smbus.c
@@ -41,27 +41,14 @@ static int smbus_do_alert(struct device *dev, void *addrp)
{
struct i2c_client *client = i2c_verify_client(dev);
struct alert_data *data = addrp;
- struct i2c_driver *driver;

if (!client || client->addr != data->addr)
return 0;
if (client->flags & I2C_CLIENT_TEN)
return 0;

- /*
- * Drivers should either disable alerts, or provide at least
- * a minimal handler. Lock so the driver won't change.
- */
- device_lock(dev);
- if (client->dev.driver) {
- driver = to_i2c_driver(client->dev.driver);
- if (driver->alert)
- driver->alert(client, data->flag);
- else
- dev_warn(&client->dev, "no driver alert()!\n");
- } else
- dev_dbg(&client->dev, "alert with no driver\n");
- device_unlock(dev);
+ if (i2c_alert(client, data->flag))
+ return 0;

/* Stop iterating after we find the device */
return -EBUSY;
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index 7ffc970..fbca48a 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -72,6 +72,9 @@ extern int i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
extern int __i2c_transfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
int num);

+/* call an alert. */
+extern int i2c_alert(struct i2c_client *client, unsigned int data);
+
/* This is the very generalized SMBus access routine. You probably do not
want to use this, though; one of the functions below may be much easier,
and probably just as fast.
--
2.4.3