All of lore.kernel.org
 help / color / mirror / Atom feed
From: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
To: robh+dt@kernel.org, mark.rutland@arm.com, peter@korsgaard.com,
	andrew@lunn.ch, palmer@sifive.com, paul.walmsley@sifive.com,
	sagar.kadam@sifive.com, linux-i2c@vger.kernel.org,
	devicetree@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v4 3/3] i2c-ocores: sifive: add polling mode workaround for FU540-C000 SoC
Date: Mon, 20 May 2019 17:50:17 +0530	[thread overview]
Message-ID: <1558354817-12034-4-git-send-email-sagar.kadam@sifive.com> (raw)
In-Reply-To: <1558354817-12034-1-git-send-email-sagar.kadam@sifive.com>

The i2c-ocore driver already has a polling mode interface.But it needs
a workaround for FU540 Chipset on HiFive unleashed board (RevA00).
There is an erratum in FU540 chip that prevents interrupt driven i2c
transfers from working, and also the I2C controller's interrupt bit
cannot be cleared if set, due to this the existing i2c polling mode
interface added in mainline earlier doesn't work, and CPU stall's
infinitely, when-ever i2c transfer is initiated.

Ref:previous polling mode support in mainline

	commit 69c8c0c0efa8 ("i2c: ocores: add polling interface")

The workaround / fix under OCORES_FLAG_BROKEN_IRQ is particularly for
FU540-COOO SoC.

Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
---
 drivers/i2c/busses/i2c-ocores.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index aee1d86..e0d7f24 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -27,6 +27,7 @@
 #include <linux/jiffies.h>
 
 #define OCORES_FLAG_POLL BIT(0)
+#define OCORES_FLAG_BROKEN_IRQ BIT(1) /* Broken IRQ for FU540-C000 SoC */
 
 /*
  * 'process_lock' exists because ocores_process() and ocores_process_timeout()
@@ -239,9 +240,13 @@ static irqreturn_t ocores_isr(int irq, void *dev_id)
 	struct ocores_i2c *i2c = dev_id;
 	u8 stat = oc_getreg(i2c, OCI2C_STATUS);
 
-	if (!(stat & OCI2C_STAT_IF))
+	if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) {
+		if (stat & OCI2C_STAT_IF)
+			if (!(stat & OCI2C_STAT_BUSY))
+				return IRQ_NONE;
+	} else if (!(stat & OCI2C_STAT_IF)) {
 		return IRQ_NONE;
-
+	}
 	ocores_process(i2c, stat);
 
 	return IRQ_HANDLED;
@@ -356,6 +361,11 @@ static void ocores_process_polling(struct ocores_i2c *i2c)
 		ret = ocores_isr(-1, i2c);
 		if (ret == IRQ_NONE)
 			break; /* all messages have been transferred */
+		else {
+			if (i2c->flags & OCORES_FLAG_BROKEN_IRQ)
+				if (i2c->state == STATE_DONE)
+					break;
+		}
 	}
 }
 
@@ -406,7 +416,7 @@ static int ocores_xfer(struct i2c_adapter *adap,
 {
 	struct ocores_i2c *i2c = i2c_get_adapdata(adap);
 
-	if (i2c->flags & OCORES_FLAG_POLL)
+	if ((i2c->flags & (OCORES_FLAG_POLL | OCORES_FLAG_BROKEN_IRQ)))
 		return ocores_xfer_polling(adap, msgs, num);
 	return ocores_xfer_core(i2c, msgs, num, false);
 }
@@ -601,6 +611,7 @@ static int ocores_i2c_probe(struct platform_device *pdev)
 {
 	struct ocores_i2c *i2c;
 	struct ocores_i2c_platform_data *pdata;
+	const struct of_device_id *match;
 	struct resource *res;
 	int irq;
 	int ret;
@@ -682,13 +693,23 @@ static int ocores_i2c_probe(struct platform_device *pdev)
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq == -ENXIO) {
-		i2c->flags |= OCORES_FLAG_POLL;
+		/*
+		 * Set a OCORES_FLAG_BROKEN_IRQ to enable workaround for
+		 * FU540-C000 SoC in polling mode interface of i2c-ocore driver.
+		 * Else enable default polling mode interface for SIFIVE/OCORE
+		 * device types.
+		 */
+		match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
+		if (match && (long)match->data == TYPE_SIFIVE_REV0)
+			i2c->flags |= OCORES_FLAG_BROKEN_IRQ;
+		else
+			i2c->flags |= OCORES_FLAG_POLL;
 	} else {
 		if (irq < 0)
 			return irq;
 	}
 
-	if (!(i2c->flags & OCORES_FLAG_POLL)) {
+	if (!(i2c->flags & (OCORES_FLAG_POLL | OCORES_FLAG_BROKEN_IRQ))) {
 		ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0,
 				       pdev->name, i2c);
 		if (ret) {
-- 
1.9.1


WARNING: multiple messages have this Message-ID (diff)
From: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
To: robh+dt@kernel.org, mark.rutland@arm.com, peter@korsgaard.com,
	andrew@lunn.ch, palmer@sifive.com, paul.walmsley@sifive.com,
	sagar.kadam@sifive.com, linux-i2c@vger.kernel.org,
	devicetree@vger.kernel.org, linux-riscv@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH v4 3/3] i2c-ocores: sifive: add polling mode workaround for FU540-C000 SoC
Date: Mon, 20 May 2019 17:50:17 +0530	[thread overview]
Message-ID: <1558354817-12034-4-git-send-email-sagar.kadam@sifive.com> (raw)
In-Reply-To: <1558354817-12034-1-git-send-email-sagar.kadam@sifive.com>

The i2c-ocore driver already has a polling mode interface.But it needs
a workaround for FU540 Chipset on HiFive unleashed board (RevA00).
There is an erratum in FU540 chip that prevents interrupt driven i2c
transfers from working, and also the I2C controller's interrupt bit
cannot be cleared if set, due to this the existing i2c polling mode
interface added in mainline earlier doesn't work, and CPU stall's
infinitely, when-ever i2c transfer is initiated.

Ref:previous polling mode support in mainline

	commit 69c8c0c0efa8 ("i2c: ocores: add polling interface")

The workaround / fix under OCORES_FLAG_BROKEN_IRQ is particularly for
FU540-COOO SoC.

Signed-off-by: Sagar Shrikant Kadam <sagar.kadam@sifive.com>
---
 drivers/i2c/busses/i2c-ocores.c | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

diff --git a/drivers/i2c/busses/i2c-ocores.c b/drivers/i2c/busses/i2c-ocores.c
index aee1d86..e0d7f24 100644
--- a/drivers/i2c/busses/i2c-ocores.c
+++ b/drivers/i2c/busses/i2c-ocores.c
@@ -27,6 +27,7 @@
 #include <linux/jiffies.h>
 
 #define OCORES_FLAG_POLL BIT(0)
+#define OCORES_FLAG_BROKEN_IRQ BIT(1) /* Broken IRQ for FU540-C000 SoC */
 
 /*
  * 'process_lock' exists because ocores_process() and ocores_process_timeout()
@@ -239,9 +240,13 @@ static irqreturn_t ocores_isr(int irq, void *dev_id)
 	struct ocores_i2c *i2c = dev_id;
 	u8 stat = oc_getreg(i2c, OCI2C_STATUS);
 
-	if (!(stat & OCI2C_STAT_IF))
+	if (i2c->flags & OCORES_FLAG_BROKEN_IRQ) {
+		if (stat & OCI2C_STAT_IF)
+			if (!(stat & OCI2C_STAT_BUSY))
+				return IRQ_NONE;
+	} else if (!(stat & OCI2C_STAT_IF)) {
 		return IRQ_NONE;
-
+	}
 	ocores_process(i2c, stat);
 
 	return IRQ_HANDLED;
@@ -356,6 +361,11 @@ static void ocores_process_polling(struct ocores_i2c *i2c)
 		ret = ocores_isr(-1, i2c);
 		if (ret == IRQ_NONE)
 			break; /* all messages have been transferred */
+		else {
+			if (i2c->flags & OCORES_FLAG_BROKEN_IRQ)
+				if (i2c->state == STATE_DONE)
+					break;
+		}
 	}
 }
 
@@ -406,7 +416,7 @@ static int ocores_xfer(struct i2c_adapter *adap,
 {
 	struct ocores_i2c *i2c = i2c_get_adapdata(adap);
 
-	if (i2c->flags & OCORES_FLAG_POLL)
+	if ((i2c->flags & (OCORES_FLAG_POLL | OCORES_FLAG_BROKEN_IRQ)))
 		return ocores_xfer_polling(adap, msgs, num);
 	return ocores_xfer_core(i2c, msgs, num, false);
 }
@@ -601,6 +611,7 @@ static int ocores_i2c_probe(struct platform_device *pdev)
 {
 	struct ocores_i2c *i2c;
 	struct ocores_i2c_platform_data *pdata;
+	const struct of_device_id *match;
 	struct resource *res;
 	int irq;
 	int ret;
@@ -682,13 +693,23 @@ static int ocores_i2c_probe(struct platform_device *pdev)
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq == -ENXIO) {
-		i2c->flags |= OCORES_FLAG_POLL;
+		/*
+		 * Set a OCORES_FLAG_BROKEN_IRQ to enable workaround for
+		 * FU540-C000 SoC in polling mode interface of i2c-ocore driver.
+		 * Else enable default polling mode interface for SIFIVE/OCORE
+		 * device types.
+		 */
+		match = of_match_node(ocores_i2c_match, pdev->dev.of_node);
+		if (match && (long)match->data == TYPE_SIFIVE_REV0)
+			i2c->flags |= OCORES_FLAG_BROKEN_IRQ;
+		else
+			i2c->flags |= OCORES_FLAG_POLL;
 	} else {
 		if (irq < 0)
 			return irq;
 	}
 
-	if (!(i2c->flags & OCORES_FLAG_POLL)) {
+	if (!(i2c->flags & (OCORES_FLAG_POLL | OCORES_FLAG_BROKEN_IRQ))) {
 		ret = devm_request_irq(&pdev->dev, irq, ocores_isr, 0,
 				       pdev->name, i2c);
 		if (ret) {
-- 
1.9.1


_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

  parent reply	other threads:[~2019-05-20 12:21 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-20 12:20 [PATCH v4 0/3] Extend dt bindings to support I2C on sifive devices and a fix broken IRQ in polling mode Sagar Shrikant Kadam
2019-05-20 12:20 ` Sagar Shrikant Kadam
2019-05-20 12:20 ` [PATCH v4 1/3] dt-bindings: i2c: extend existing opencore bindings Sagar Shrikant Kadam
2019-05-20 12:20   ` Sagar Shrikant Kadam
2019-05-20 12:20 ` [PATCH v4 2/3] i2c-ocores: sifive: add support for i2c device on FU540-c000 SoC Sagar Shrikant Kadam
2019-05-20 12:20   ` Sagar Shrikant Kadam
2019-05-20 12:20 ` Sagar Shrikant Kadam [this message]
2019-05-20 12:20   ` [PATCH v4 3/3] i2c-ocores: sifive: add polling mode workaround for FU540-C000 SoC Sagar Shrikant Kadam
2019-05-20 12:41   ` Andrew Lunn
2019-05-20 12:41     ` Andrew Lunn
2019-05-20 12:41     ` Andrew Lunn
2019-05-20 13:27     ` Sagar Kadam
2019-05-20 13:27       ` Sagar Kadam

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1558354817-12034-4-git-send-email-sagar.kadam@sifive.com \
    --to=sagar.kadam@sifive.com \
    --cc=andrew@lunn.ch \
    --cc=devicetree@vger.kernel.org \
    --cc=linux-i2c@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-riscv@lists.infradead.org \
    --cc=mark.rutland@arm.com \
    --cc=palmer@sifive.com \
    --cc=paul.walmsley@sifive.com \
    --cc=peter@korsgaard.com \
    --cc=robh+dt@kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.