Commit c467d919 authored by Heiner Kallweit's avatar Heiner Kallweit Committed by Wolfram Sang
Browse files

i2c: i801: improve interrupt handler 



Not sure if it can happen, but better play safe: If SMBHSTSTS_BYTE_DONE
and an error flag is set, then don't trust the result and skip calling
i801_isr_byte_done(). In addition clear status bit SMBHSTSTS_BYTE_DONE
in the main interrupt handler, this allows to simplify the code a
little.

Signed-off-by: default avatarHeiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: default avatarJean Delvare <jdelvare@suse.de>
Signed-off-by: default avatarWolfram Sang <wsa@kernel.org>
parent fce55da3

drivers/i2c/busses/i2c-i801.c

+8 −17
Original line number Diff line number Diff line
@@ -558,9 +558,6 @@ static void i801_isr_byte_done(struct i801_priv *priv) 
		/* 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));

}



static irqreturn_t i801_host_notify_isr(struct i801_priv *priv)
@@ -590,7 +587,6 @@ static irqreturn_t i801_host_notify_isr(struct i801_priv *priv) 
 *      BUS_ERR - SMI# transaction collision

 *      FAILED - transaction was canceled due to a KILL request

 *    When any of these occur, update ->status and signal completion.

 *    ->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.
@@ -615,23 +611,18 @@ static irqreturn_t i801_isr(int irq, void *dev_id) 
	}



	status = inb_p(SMBHSTSTS(priv));

	if (status & SMBHSTSTS_BYTE_DONE)

	if ((status & (SMBHSTSTS_BYTE_DONE | STATUS_ERROR_FLAGS)) == SMBHSTSTS_BYTE_DONE)

		i801_isr_byte_done(priv);



	/*

	 * Clear remaining IRQ sources: Completion of last command, errors

	 * and the SMB_ALERT signal. SMB_ALERT status is set after signal

	 * assertion independently of the interrupt generation being blocked

	 * or not so clear it always when the status is set.

	 * Clear IRQ sources: SMB_ALERT status is set after signal assertion

	 * independently of the interrupt generation being blocked or not

	 * so clear it always when the status is set.

	 */

	status &= SMBHSTSTS_INTR | STATUS_ERROR_FLAGS | SMBHSTSTS_SMBALERT_STS;

	if (status)

	status &= STATUS_FLAGS | SMBHSTSTS_SMBALERT_STS;

	outb_p(status, SMBHSTSTS(priv));

	status &= ~SMBHSTSTS_SMBALERT_STS; /* SMB_ALERT not reported */

	/*

	 * Report transaction result.

	 * ->status must be cleared before the next transaction is started.

	 */



	status &= STATUS_ERROR_FLAGS | SMBHSTSTS_INTR;

	if (status) {

		priv->status = status;

		complete(&priv->done);