diff options
Diffstat (limited to 'drivers/i2c/busses/i2c-i801.c')
| -rw-r--r-- | drivers/i2c/busses/i2c-i801.c | 343 |
1 files changed, 255 insertions, 88 deletions
diff --git a/drivers/i2c/busses/i2c-i801.c b/drivers/i2c/busses/i2c-i801.c index ae2945a5e007..898dcf9c7ade 100644 --- a/drivers/i2c/busses/i2c-i801.c +++ b/drivers/i2c/busses/i2c-i801.c @@ -60,10 +60,12 @@ Block process call transaction no I2C block read transaction yes (doesn't use the block buffer) Slave mode no + Interrupt processing yes See the file Documentation/i2c/busses/i2c-i801 for details. */ +#include <linux/interrupt.h> #include <linux/module.h> #include <linux/pci.h> #include <linux/kernel.h> @@ -76,6 +78,7 @@ #include <linux/io.h> #include <linux/dmi.h> #include <linux/slab.h> +#include <linux/wait.h> /* I801 SMBus address offsets */ #define SMBHSTSTS(p) (0 + (p)->smba) @@ -91,8 +94,12 @@ /* PCI Address Constants */ #define SMBBAR 4 +#define SMBPCISTS 0x006 #define SMBHSTCFG 0x040 +/* Host status bits for SMBPCISTS */ +#define SMBPCISTS_INTS 0x08 + /* Host configuration bits for SMBHSTCFG */ #define SMBHSTCFG_HST_EN 1 #define SMBHSTCFG_SMB_SMI_EN 2 @@ -102,12 +109,8 @@ #define SMBAUXCTL_CRC 1 #define SMBAUXCTL_E32B 2 -/* kill bit for SMBHSTCNT */ -#define SMBHSTCNT_KILL 2 - /* Other settings */ #define MAX_RETRIES 400 -#define ENABLE_INT9 0 /* set to 0x01 to enable - untested */ /* I801 command constants */ #define I801_QUICK 0x00 @@ -117,10 +120,13 @@ #define I801_PROC_CALL 0x10 /* unimplemented */ #define I801_BLOCK_DATA 0x14 #define I801_I2C_BLOCK_DATA 0x18 /* ICH5 and later */ -#define I801_BLOCK_LAST 0x34 -#define I801_I2C_BLOCK_LAST 0x38 /* ICH5 and later */ -#define I801_START 0x40 -#define I801_PEC_EN 0x80 /* ICH3 and later */ + +/* I801 Host Control register bits */ +#define SMBHSTCNT_INTREN 0x01 +#define SMBHSTCNT_KILL 0x02 +#define SMBHSTCNT_LAST_BYTE 0x20 +#define SMBHSTCNT_START 0x40 +#define SMBHSTCNT_PEC_EN 0x80 /* ICH3 and later */ /* I801 Hosts Status register bits */ #define SMBHSTSTS_BYTE_DONE 0x80 @@ -132,9 +138,11 @@ #define SMBHSTSTS_INTR 0x02 #define SMBHSTSTS_HOST_BUSY 0x01 -#define STATUS_FLAGS (SMBHSTSTS_BYTE_DONE | SMBHSTSTS_FAILED | \ - SMBHSTSTS_BUS_ERR | SMBHSTSTS_DEV_ERR | \ - SMBHSTSTS_INTR) +#define STATUS_ERROR_FLAGS (SMBHSTSTS_FAILED | SMBHSTSTS_BUS_ERR | \ + SMBHSTSTS_DEV_ERR) + +#define STATUS_FLAGS (SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR | \ + STATUS_ERROR_FLAGS) /* Older devices have their ID defined in <linux/pci_ids.h> */ #define PCI_DEVICE_ID_INTEL_COUGARPOINT_SMBUS 0x1c22 @@ -154,6 +162,17 @@ struct i801_priv { unsigned char original_hstcfg; struct pci_dev *pci_dev; unsigned int features; + + /* isr processing */ + wait_queue_head_t waitq; + u8 status; + + /* Command state used by isr for byte-by-byte block transactions */ + u8 cmd; + bool is_read; + int count; + int len; + u8 *data; }; static struct pci_driver i801_driver; @@ -162,6 +181,7 @@ static struct pci_driver i801_driver; #define FEATURE_BLOCK_BUFFER (1 << 1) #define FEATURE_BLOCK_PROC (1 << 2) #define FEATURE_I2C_BLOCK_READ (1 << 3) +#define FEATURE_IRQ (1 << 4) /* Not really a feature, but it's convenient to handle it as such */ #define FEATURE_IDF (1 << 15) @@ -170,6 +190,7 @@ static const char *i801_feature_names[] = { "Block buffer", "Block process call", "I2C block read", + "Interrupt", }; static unsigned int disable_features; @@ -205,13 +226,22 @@ static int i801_check_pre(struct i801_priv *priv) return 0; } -/* Convert the status register to an error code, and clear it. */ -static int i801_check_post(struct i801_priv *priv, int status, int timeout) +/* + * Convert the status register to an error code, and clear it. + * Note that status only contains the bits we want to clear, not the + * actual register value. + */ +static int i801_check_post(struct i801_priv *priv, int status) { int result = 0; - /* If the SMBus is still busy, we give up */ - if (timeout) { + /* + * If the SMBus is still busy, we give up + * Note: This timeout condition only happens when using polling + * transactions. For interrupt operation, NAK/timeout is indicated by + * DEV_ERR. + */ + if (unlikely(status < 0)) { dev_err(&priv->pci_dev->dev, "Transaction timeout\n"); /* try to stop the current command */ dev_dbg(&priv->pci_dev->dev, "Terminating the current operation\n"); @@ -244,64 +274,76 @@ static int i801_check_post(struct i801_priv *priv, int status, int timeout) dev_dbg(&priv->pci_dev->dev, "Lost arbitration\n"); } - if (result) { - /* Clear error flags */ - outb_p(status & STATUS_FLAGS, SMBHSTSTS(priv)); - status = inb_p(SMBHSTSTS(priv)) & STATUS_FLAGS; - if (status) { - dev_warn(&priv->pci_dev->dev, "Failed clearing status " - "flags at end of transaction (%02x)\n", - status); - } - } + /* Clear status flags except BYTE_DONE, to be cleared by caller */ + outb_p(status, SMBHSTSTS(priv)); return result; } -static int i801_transaction(struct i801_priv *priv, int xact) +/* Wait for BUSY being cleared and either INTR or an error flag being set */ +static int i801_wait_intr(struct i801_priv *priv) { - int status; - int result; int timeout = 0; - - result = i801_check_pre(priv); - if (result < 0) - return result; - - /* the current contents of SMBHSTCNT can be overwritten, since PEC, - * INTREN, SMBSCMD are passed in xact */ - outb_p(xact | I801_START, SMBHSTCNT(priv)); + int status; /* We will always wait for a fraction of a second! */ do { usleep_range(250, 500); status = inb_p(SMBHSTSTS(priv)); - } while ((status & SMBHSTSTS_HOST_BUSY) && (timeout++ < MAX_RETRIES)); + } while (((status & SMBHSTSTS_HOST_BUSY) || + !(status & (STATUS_ERROR_FLAGS | SMBHSTSTS_INTR))) && + (timeout++ < MAX_RETRIES)); - result = i801_check_post(priv, status, timeout > MAX_RETRIES); - if (result < 0) - return result; - - outb_p(SMBHSTSTS_INTR, SMBHSTSTS(priv)); - return 0; + if (timeout > MAX_RETRIES) { + dev_dbg(&priv->pci_dev->dev, "INTR Timeout!\n"); + return -ETIMEDOUT; + } + return status & (STATUS_ERROR_FLAGS | SMBHSTSTS_INTR); } -/* wait for INTR bit as advised by Intel */ -static void i801_wait_hwpec(struct i801_priv *priv) +/* Wait for either BYTE_DONE or an error flag being set */ +static int i801_wait_byte_done(struct i801_priv *priv) { int timeout = 0; int status; + /* We will always wait for a fraction of a second! */ do { usleep_range(250, 500); status = inb_p(SMBHSTSTS(priv)); - } while ((!(status & SMBHSTSTS_INTR)) - && (timeout++ < MAX_RETRIES)); + } while (!(status & (STATUS_ERROR_FLAGS | SMBHSTSTS_BYTE_DONE)) && + (timeout++ < MAX_RETRIES)); - if (timeout > MAX_RETRIES) - dev_dbg(&priv->pci_dev->dev, "PEC Timeout!\n"); + if (timeout > MAX_RETRIES) { + dev_dbg(&priv->pci_dev->dev, "BYTE_DONE Timeout!\n"); + return -ETIMEDOUT; + } + return status & STATUS_ERROR_FLAGS; +} - outb_p(status, SMBHSTSTS(priv)); +static int i801_transaction(struct i801_priv *priv, int xact) +{ + int status; + int result; + + result = i801_check_pre(priv); + if (result < 0) + return result; + + if (priv->features & FEATURE_IRQ) { + outb_p(xact | SMBHSTCNT_INTREN | SMBHSTCNT_START, + SMBHSTCNT(priv)); + wait_event(priv->waitq, (status = priv->status)); + priv->status = 0; + return i801_check_post(priv, status); + } + + /* the current contents of SMBHSTCNT can be overwritten, since PEC, + * SMBSCMD are passed in xact */ + outb_p(xact | SMBHSTCNT_START, SMBHSTCNT(priv)); + + status = i801_wait_intr(priv); + return i801_check_post(priv, status); } static int i801_block_transaction_by_block(struct i801_priv *priv, @@ -321,8 +363,8 @@ static int i801_block_transaction_by_block(struct i801_priv *priv, outb_p(data->block[i+1], SMBBLKDAT(priv)); } - status = i801_transaction(priv, I801_BLOCK_DATA | ENABLE_INT9 | - I801_PEC_EN * hwpec); + status = i801_transaction(priv, I801_BLOCK_DATA | + (hwpec ? SMBHSTCNT_PEC_EN : 0)); if (status) return status; @@ -338,6 +380,98 @@ static int i801_block_transaction_by_block(struct i801_priv *priv, return 0; } +static void i801_isr_byte_done(struct i801_priv *priv) +{ + if (priv->is_read) { + /* For SMBus block reads, length is received with first byte */ + if (((priv->cmd & 0x1c) == I801_BLOCK_DATA) && + (priv->count == 0)) { + priv->len = inb_p(SMBHSTDAT0(priv)); + if (priv->len < 1 || priv->len > I2C_SMBUS_BLOCK_MAX) { + dev_err(&priv->pci_dev->dev, + "Illegal SMBus block read size %d\n", + priv->len); + /* FIXME: Recover */ + priv->len = I2C_SMBUS_BLOCK_MAX; + } else { + dev_dbg(&priv->pci_dev->dev, + "SMBus block read size is %d\n", + priv->len); + } + priv->data[-1] = priv->len; + } + + /* Read next byte */ + if (priv->count < priv->len) + priv->data[priv->count++] = inb(SMBBLKDAT(priv)); + else + dev_dbg(&priv->pci_dev->dev, + "Discarding extra byte on block read\n"); + + /* Set LAST_BYTE for last byte of read transaction */ + if (priv->count == priv->len - 1) + outb_p(priv->cmd | SMBHSTCNT_LAST_BYTE, + SMBHSTCNT(priv)); + } else if (priv->count < priv->len - 1) { + /* Write next byte, except for IRQ after last byte */ + outb_p(priv->data[++priv->count], SMBBLKDAT(priv)); + } + + /* Clear BYTE_DONE to continue with next byte */ + outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv)); +} + +/* + * There are two kinds of interrupts: + * + * 1) i801 signals transaction completion with one of these interrupts: + * INTR - Success + * DEV_ERR - Invalid command, NAK or communication timeout + * BUS_ERR - SMI# transaction collision + * FAILED - transaction was canceled due to a KILL request + * When any of these occur, update ->status and wake up the waitq. + * ->status must be cleared before kicking off the next transaction. + * + * 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. + */ +static irqreturn_t i801_isr(int irq, void *dev_id) +{ + struct i801_priv *priv = dev_id; + u16 pcists; + u8 status; + + /* Confirm this is our interrupt */ + pci_read_config_word(priv->pci_dev, SMBPCISTS, &pcists); + if (!(pcists & SMBPCISTS_INTS)) + return IRQ_NONE; + + status = inb_p(SMBHSTSTS(priv)); + if (status != 0x42) + dev_dbg(&priv->pci_dev->dev, "irq: status = %02x\n", status); + + if (status & SMBHSTSTS_BYTE_DONE) + i801_isr_byte_done(priv); + + /* + * Clear irq sources and report transaction result. + * ->status must be cleared before the next transaction is started. + */ + status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS; + if (status) { + outb_p(status, SMBHSTSTS(priv)); + priv->status |= status; + wake_up(&priv->waitq); + } + + return IRQ_HANDLED; +} + +/* + * For "byte-by-byte" block transactions: + * I2C write uses cmd=I801_BLOCK_DATA, I2C_EN=1 + * I2C read uses cmd=I801_I2C_BLOCK_DATA + */ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, union i2c_smbus_data *data, char read_write, int command, @@ -347,7 +481,6 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, int smbcmd; int status; int result; - int timeout; result = i801_check_pre(priv); if (result < 0) @@ -360,36 +493,39 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, outb_p(data->block[1], SMBBLKDAT(priv)); } + if (command == I2C_SMBUS_I2C_BLOCK_DATA && + read_write == I2C_SMBUS_READ) + smbcmd = I801_I2C_BLOCK_DATA; + else + smbcmd = I801_BLOCK_DATA; + + if (priv->features & FEATURE_IRQ) { + priv->is_read = (read_write == I2C_SMBUS_READ); + if (len == 1 && priv->is_read) + smbcmd |= SMBHSTCNT_LAST_BYTE; + priv->cmd = smbcmd | SMBHSTCNT_INTREN; + priv->len = len; + priv->count = 0; + priv->data = &data->block[1]; + + outb_p(priv->cmd | SMBHSTCNT_START, SMBHSTCNT(priv)); + wait_event(priv->waitq, (status = priv->status)); + priv->status = 0; + return i801_check_post(priv, status); + } + for (i = 1; i <= len; i++) { - if (i == len && read_write == I2C_SMBUS_READ) { - if (command == I2C_SMBUS_I2C_BLOCK_DATA) - smbcmd = I801_I2C_BLOCK_LAST; - else - smbcmd = I801_BLOCK_LAST; - } else { - if (command == I2C_SMBUS_I2C_BLOCK_DATA - && read_write == I2C_SMBUS_READ) - smbcmd = I801_I2C_BLOCK_DATA; - else - smbcmd = I801_BLOCK_DATA; - } - outb_p(smbcmd | ENABLE_INT9, SMBHSTCNT(priv)); + if (i == len && read_write == I2C_SMBUS_READ) + smbcmd |= SMBHSTCNT_LAST_BYTE; + outb_p(smbcmd, SMBHSTCNT(priv)); if (i == 1) - outb_p(inb(SMBHSTCNT(priv)) | I801_START, + outb_p(inb(SMBHSTCNT(priv)) | SMBHSTCNT_START, SMBHSTCNT(priv)); - /* We will always wait for a fraction of a second! */ - timeout = 0; - do { - usleep_range(250, 500); - status = inb_p(SMBHSTSTS(priv)); - } while ((!(status & SMBHSTSTS_BYTE_DONE)) - && (timeout++ < MAX_RETRIES)); - - result = i801_check_post(priv, status, timeout > MAX_RETRIES); - if (result < 0) - return result; + status = i801_wait_byte_done(priv); + if (status) + goto exit; if (i == 1 && read_write == I2C_SMBUS_READ && command != I2C_SMBUS_I2C_BLOCK_DATA) { @@ -416,10 +552,12 @@ static int i801_block_transaction_byte_by_byte(struct i801_priv *priv, outb_p(data->block[i+1], SMBBLKDAT(priv)); /* signals SMBBLKDAT ready */ - outb_p(SMBHSTSTS_BYTE_DONE | SMBHSTSTS_INTR, SMBHSTSTS(priv)); + outb_p(SMBHSTSTS_BYTE_DONE, SMBHSTSTS(priv)); } - return 0; + status = i801_wait_intr(priv); +exit: + return i801_check_post(priv, status); } static int i801_set_block_buffer_mode(struct i801_priv *priv) @@ -474,9 +612,6 @@ static int i801_block_transaction(struct i801_priv *priv, read_write, command, hwpec); - if (result == 0 && hwpec) - i801_wait_hwpec(priv); - if (command == I2C_SMBUS_I2C_BLOCK_DATA && read_write == I2C_SMBUS_WRITE) { /* restore saved configuration register value */ @@ -564,7 +699,7 @@ static s32 i801_access(struct i2c_adapter *adap, u16 addr, ret = i801_block_transaction(priv, data, read_write, size, hwpec); else - ret = i801_transaction(priv, xact | ENABLE_INT9); + ret = i801_transaction(priv, xact); /* Some BIOSes don't like it when PEC is enabled at reboot or resume time, so we forcibly disable it after every transaction. Turn off @@ -799,6 +934,16 @@ static int __devinit i801_probe(struct pci_dev *dev, break; } + /* IRQ processing tested on CougarPoint PCH, ICH5, ICH7-M and ICH10 */ + if (dev->device == PCI_DEVICE_ID_INTEL_COUGARPOINT_SMBUS || + dev->device == PCI_DEVICE_ID_INTEL_82801EB_3 || + dev->device == PCI_DEVICE_ID_INTEL_ICH7_17 || + dev->device == PCI_DEVICE_ID_INTEL_ICH8_5 || + dev->device == PCI_DEVICE_ID_INTEL_ICH9_6 || + dev->device == PCI_DEVICE_ID_INTEL_ICH10_4 || + dev->device == PCI_DEVICE_ID_INTEL_ICH10_5) + priv->features |= FEATURE_IRQ; + /* Disable features on user request */ for (i = 0; i < ARRAY_SIZE(i801_feature_names); i++) { if (priv->features & disable_features & (1 << i)) @@ -846,16 +991,30 @@ static int __devinit i801_probe(struct pci_dev *dev, } pci_write_config_byte(priv->pci_dev, SMBHSTCFG, temp); - if (temp & SMBHSTCFG_SMB_SMI_EN) + if (temp & SMBHSTCFG_SMB_SMI_EN) { dev_dbg(&dev->dev, "SMBus using interrupt SMI#\n"); - else - dev_dbg(&dev->dev, "SMBus using PCI Interrupt\n"); + /* Disable SMBus interrupt feature if SMBus using SMI# */ + priv->features &= ~FEATURE_IRQ; + } /* Clear special mode bits */ if (priv->features & (FEATURE_SMBUS_PEC | FEATURE_BLOCK_BUFFER)) outb_p(inb_p(SMBAUXCTL(priv)) & ~(SMBAUXCTL_CRC | SMBAUXCTL_E32B), SMBAUXCTL(priv)); + if (priv->features & FEATURE_IRQ) { + init_waitqueue_head(&priv->waitq); + + err = request_irq(dev->irq, i801_isr, IRQF_SHARED, + i801_driver.name, priv); + if (err) { + dev_err(&dev->dev, "Failed to allocate irq %d: %d\n", + dev->irq, err); + goto exit_release; + } + dev_info(&dev->dev, "SMBus using PCI Interrupt\n"); + } + /* set up the sysfs linkage to our parent device */ priv->adapter.dev.parent = &dev->dev; @@ -867,14 +1026,18 @@ static int __devinit i801_probe(struct pci_dev *dev, err = i2c_add_adapter(&priv->adapter); if (err) { dev_err(&dev->dev, "Failed to add SMBus adapter\n"); - goto exit_release; + goto exit_free_irq; } i801_probe_optional_slaves(priv); pci_set_drvdata(dev, priv); + return 0; +exit_free_irq: + if (priv->features & FEATURE_IRQ) + free_irq(dev->irq, priv); exit_release: pci_release_region(dev, SMBBAR); exit: @@ -888,7 +1051,11 @@ static void __devexit i801_remove(struct pci_dev *dev) i2c_del_adapter(&priv->adapter); pci_write_config_byte(dev, SMBHSTCFG, priv->original_hstcfg); + + if (priv->features & FEATURE_IRQ) + free_irq(dev->irq, priv); pci_release_region(dev, SMBBAR); + pci_set_drvdata(dev, NULL); kfree(priv); /* |