From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Date: Thu, 12 Nov 2015 14:31:51 +0000 Subject: [PATCH v2 06/10] i2c: rcar: init new messages in irq Message-Id: <1447338715-9955-7-git-send-email-wsa@the-dreams.de> List-Id: References: <1447338715-9955-1-git-send-email-wsa@the-dreams.de> In-Reply-To: <1447338715-9955-1-git-send-email-wsa@the-dreams.de> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-i2c@vger.kernel.org Cc: linux-sh@vger.kernel.org, Magnus Damm , Simon Horman , Laurent Pinchart , Geert Uytterhoeven , Wolfram Sang , Yoshihiro Shimoda , Kuninori Morimoto From: Wolfram Sang Setting up new messages was done in process context while handling a message was in interrupt context. Because of the HW design, this IP core is sensitive to timing, so the context switches were too expensive. Move this setup to interrupt context as well. In my test setup, this fixed the occasional 'data byte sent twice' issue which a number of people have seen. It also fixes to send REP_START after a read message which was wrongly send as a STOP + START sequence before. Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-rcar.c | 74 +++++++++++++++++++++---------------------- 1 file changed, 37 insertions(+), 37 deletions(-) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 4bd3099865b485..316de40fa4dc69 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -267,6 +267,13 @@ static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv) rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND); } +static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv) +{ + priv->msg++; + priv->msgs_left--; + rcar_i2c_prepare_msg(priv); +} + /* * interrupt functions */ @@ -309,21 +316,17 @@ static int rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr) * [ICRXTX] -> [SHIFT] -> [I2C bus] */ - if (priv->flags & ID_LAST_MSG) + if (priv->flags & ID_LAST_MSG) { /* * If current msg is the _LAST_ msg, * prepare stop condition here. * ID_DONE will be set on STOP irq. */ rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP); - else - /* - * If current msg is _NOT_ last msg, - * it doesn't call stop phase. - * thus, there is no STOP irq. - * return ID_DONE here. - */ - return ID_DONE; + } else { + rcar_i2c_next_msg(priv); + return 0; + } } rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_SEND); @@ -367,7 +370,10 @@ static int rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr) else rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA); - rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV); + if (priv->pos = msg->len && !(priv->flags & ID_LAST_MSG)) + rcar_i2c_next_msg(priv); + else + rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV); return 0; } @@ -462,6 +468,7 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr) /* Stop */ if (msr & MST) { + priv->msgs_left--; /* The last message also made it */ rcar_i2c_flags_set(priv, ID_DONE); goto out; } @@ -501,35 +508,28 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap, /* This HW can't send STOP after address phase */ if (msgs[i].len = 0) { ret = -EOPNOTSUPP; - break; - } - - /* init each data */ - priv->msg = &msgs[i]; - priv->msgs_left = num - i; - - rcar_i2c_prepare_msg(priv); - - time_left = wait_event_timeout(priv->wait, - rcar_i2c_flags_has(priv, ID_DONE), - adap->timeout); - if (!time_left) { - rcar_i2c_init(priv); - ret = -ETIMEDOUT; - break; - } - - if (rcar_i2c_flags_has(priv, ID_NACK)) { - ret = -ENXIO; - break; - } - - if (rcar_i2c_flags_has(priv, ID_ARBLOST)) { - ret = -EAGAIN; - break; + goto out; } + } - ret = i + 1; /* The number of transfer */ + /* init data */ + priv->msg = msgs; + priv->msgs_left = num; + + rcar_i2c_prepare_msg(priv); + + time_left = wait_event_timeout(priv->wait, + rcar_i2c_flags_has(priv, ID_DONE), + num * adap->timeout); + if (!time_left) { + rcar_i2c_init(priv); + ret = -ETIMEDOUT; + } else if (rcar_i2c_flags_has(priv, ID_NACK)) { + ret = -ENXIO; + } else if (rcar_i2c_flags_has(priv, ID_ARBLOST)) { + ret = -EAGAIN; + } else { + ret = num - priv->msgs_left; /* The number of transfer */ } out: pm_runtime_put(dev); -- 2.1.4 From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: [PATCH v2 06/10] i2c: rcar: init new messages in irq Date: Thu, 12 Nov 2015 15:31:51 +0100 Message-ID: <1447338715-9955-7-git-send-email-wsa@the-dreams.de> References: <1447338715-9955-1-git-send-email-wsa@the-dreams.de> Return-path: In-Reply-To: <1447338715-9955-1-git-send-email-wsa@the-dreams.de> Sender: linux-sh-owner@vger.kernel.org To: linux-i2c@vger.kernel.org Cc: linux-sh@vger.kernel.org, Magnus Damm , Simon Horman , Laurent Pinchart , Geert Uytterhoeven , Wolfram Sang , Yoshihiro Shimoda , Kuninori Morimoto List-Id: linux-i2c@vger.kernel.org From: Wolfram Sang Setting up new messages was done in process context while handling a message was in interrupt context. Because of the HW design, this IP core is sensitive to timing, so the context switches were too expensive. Move this setup to interrupt context as well. In my test setup, this fixed the occasional 'data byte sent twice' issue which a number of people have seen. It also fixes to send REP_START after a read message which was wrongly send as a STOP + START sequence before. Signed-off-by: Wolfram Sang --- drivers/i2c/busses/i2c-rcar.c | 74 +++++++++++++++++++++---------------------- 1 file changed, 37 insertions(+), 37 deletions(-) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 4bd3099865b485..316de40fa4dc69 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -267,6 +267,13 @@ static void rcar_i2c_prepare_msg(struct rcar_i2c_priv *priv) rcar_i2c_write(priv, ICMIER, read ? RCAR_IRQ_RECV : RCAR_IRQ_SEND); } +static void rcar_i2c_next_msg(struct rcar_i2c_priv *priv) +{ + priv->msg++; + priv->msgs_left--; + rcar_i2c_prepare_msg(priv); +} + /* * interrupt functions */ @@ -309,21 +316,17 @@ static int rcar_i2c_irq_send(struct rcar_i2c_priv *priv, u32 msr) * [ICRXTX] -> [SHIFT] -> [I2C bus] */ - if (priv->flags & ID_LAST_MSG) + if (priv->flags & ID_LAST_MSG) { /* * If current msg is the _LAST_ msg, * prepare stop condition here. * ID_DONE will be set on STOP irq. */ rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_STOP); - else - /* - * If current msg is _NOT_ last msg, - * it doesn't call stop phase. - * thus, there is no STOP irq. - * return ID_DONE here. - */ - return ID_DONE; + } else { + rcar_i2c_next_msg(priv); + return 0; + } } rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_SEND); @@ -367,7 +370,10 @@ static int rcar_i2c_irq_recv(struct rcar_i2c_priv *priv, u32 msr) else rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA); - rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV); + if (priv->pos == msg->len && !(priv->flags & ID_LAST_MSG)) + rcar_i2c_next_msg(priv); + else + rcar_i2c_write(priv, ICMSR, RCAR_IRQ_ACK_RECV); return 0; } @@ -462,6 +468,7 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr) /* Stop */ if (msr & MST) { + priv->msgs_left--; /* The last message also made it */ rcar_i2c_flags_set(priv, ID_DONE); goto out; } @@ -501,35 +508,28 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap, /* This HW can't send STOP after address phase */ if (msgs[i].len == 0) { ret = -EOPNOTSUPP; - break; - } - - /* init each data */ - priv->msg = &msgs[i]; - priv->msgs_left = num - i; - - rcar_i2c_prepare_msg(priv); - - time_left = wait_event_timeout(priv->wait, - rcar_i2c_flags_has(priv, ID_DONE), - adap->timeout); - if (!time_left) { - rcar_i2c_init(priv); - ret = -ETIMEDOUT; - break; - } - - if (rcar_i2c_flags_has(priv, ID_NACK)) { - ret = -ENXIO; - break; - } - - if (rcar_i2c_flags_has(priv, ID_ARBLOST)) { - ret = -EAGAIN; - break; + goto out; } + } - ret = i + 1; /* The number of transfer */ + /* init data */ + priv->msg = msgs; + priv->msgs_left = num; + + rcar_i2c_prepare_msg(priv); + + time_left = wait_event_timeout(priv->wait, + rcar_i2c_flags_has(priv, ID_DONE), + num * adap->timeout); + if (!time_left) { + rcar_i2c_init(priv); + ret = -ETIMEDOUT; + } else if (rcar_i2c_flags_has(priv, ID_NACK)) { + ret = -ENXIO; + } else if (rcar_i2c_flags_has(priv, ID_ARBLOST)) { + ret = -EAGAIN; + } else { + ret = num - priv->msgs_left; /* The number of transfer */ } out: pm_runtime_put(dev); -- 2.1.4