Fixed i2c-mpc driver for multi-master i2c busses.
Subsystems (2)
PATCH 1/1 Fixed i2c-mpc driver for multi-master i2c busses.
Fixed i2c-mpc driver for multi-master i2c busses.
Simply retry on arbitration lost until xfer is successfull, a non-arbitration-lost error is triggered or the 1s timeout is hit.
Tested with a freescale MPC8349E host cpu.
Signed-off-by Clifford Wolf <[email protected]>
drivers/i2c/busses/i2c-mpc.c +14 -8
@@ -133,16 +133,16 @@if (result <0 )return result; +if (x &CSR_MAL ) { +pr_debug ("I2C: MAL\n" ); +return -EAGAIN ; + } +if (!(x &CSR_MCF )) {pr_debug ("I2C: unfinished\n" );return -EIO ; } -if (x &CSR_MAL ) { -pr_debug ("I2C: MAL\n" ); -return -EIO ; - } -if (writing && (x &CSR_RXAK )) {pr_debug ("I2C: No RXAK\n" );/* generate stop */
@@ -256,11 +256,11 @@static int mpc_xfer (struct i2c_adapter *adap,struct i2c_msg *msgs,int num) {struct i2c_msg *pmsg; -int i; -int ret =0 ; +int i, ret;unsigned long orig_jiffies = jiffies;struct mpc_i2c *i2c =i2c_get_adapdata (adap); +restart:mpc_i2c_start (i2c);/* Allow bus up to 1s to become not busy */
@@ -280,7 +280,7 @@schedule (); } -for (i =0 ; ret >=0 && i < num; i++) { +for (i =0 , ret =0 ; ret >=0 && i < num; i++) { pmsg = &msgs[i]; pr_debug("Doing %s %d bytes to 0x%02x - %d of %d messages\n", pmsg->flags & I2C_M_RD ? "read" : "write",
@@ -291,7 +291,13 @@else ret =mpc_write (i2c, pmsg->addr, pmsg->buf, pmsg->len, i); +if (ret == -EAGAIN ) { +pr_debug ("Lost i2c arbitration -> retry.\n" ); +mpc_i2c_stop (i2c); + goto restart; + } } +mpc_i2c_stop (i2c);return (ret <0 ) ? ret : num; }
(cc [email protected])
Quoted 9 lines · On Mon, 22 Dec 2008 14:55:42 +0100 Clifford Wolf <[email protected]> wrote:
Fixed i2c-mpc driver for multi-master i2c busses.
Simply retry on arbitration lost until xfer is successfull, a non-arbitration-lost error is triggered or the 1s timeout is hit.
Tested with a freescale MPC8349E host cpu.
Signed-off-by Clifford Wolf <[email protected]>
From: Clifford Wolf <[email protected]>
Simply retry on arbitration lost until xfer is successfull, a non-arbitration-lost error is triggered or the 1s timeout is hit.
Tested with a freescale MPC8349E host cpu.
Signed-off-by Clifford Wolf <[email protected]>
Signed-off-by Andrew Morton <[email protected]>
---
drivers/i2c/busses/i2c-mpc.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-)
drivers/i2c/busses/i2c-mpc.c renamed from drivers/i2c/busses/i2c-mpc.c~fixed-i2c-mpc-driver-for-multi-master-i2c-busses +14 -8
@@ -134,13 +134,13 @@ static int i2c_wait(struct mpc_i2c *i2c,if (result <0 )return result; -if (!(x &CSR_MCF )) { -pr_debug ("I2C: unfinished\n" ); -return -EIO ; - } -if (x &CSR_MAL ) {pr_debug ("I2C: MAL\n" ); +return -EAGAIN ; + } + +if (!(x &CSR_MCF )) { +pr_debug ("I2C: unfinished\n" );return -EIO ; }
@@ -257,11 +257,11 @@ static int mpc_read(struct mpc_i2c *i2c,static int mpc_xfer (struct i2c_adapter *adap,struct i2c_msg *msgs,int num) {struct i2c_msg *pmsg; -int i; -int ret =0 ; +int i, ret;unsigned long orig_jiffies = jiffies;struct mpc_i2c *i2c =i2c_get_adapdata (adap); +restart:mpc_i2c_start (i2c);/* Allow bus up to 1s to become not busy */
@@ -281,7 +281,7 @@ static int mpc_xfer(struct i2c_adapter *schedule (); } -for (i =0 ; ret >=0 && i < num; i++) { +for (i =0 , ret =0 ; ret >=0 && i < num; i++) { pmsg = &msgs[i]; pr_debug("Doing %s %d bytes to 0x%02x - %d of %d messages\n", pmsg->flags & I2C_M_RD ? "read" : "write",
@@ -292,7 +292,13 @@ static int mpc_xfer(struct i2c_adapter *else ret =mpc_write (i2c, pmsg->addr, pmsg->buf, pmsg->len, i); +if (ret == -EAGAIN ) { +pr_debug ("Lost i2c arbitration -> retry.\n" ); +mpc_i2c_stop (i2c); + goto restart; + } } +mpc_i2c_stop (i2c);return (ret <0 ) ? ret : num; }
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