All of lore.kernel.org
 help / color / mirror / Atom feed
From: Eddie James <eajames@linux.ibm.com>
To: linux-spi@vger.kernel.org
Cc: linux-kernel@vger.kernel.org, broonie@kernel.org, joel@jms.id.au,
	openbmc@lists.ozlabs.org, Eddie James <eajames@linux.ibm.com>
Subject: [PATCH] spi: fsi: Implement a timeout for polling status
Date: Thu, 17 Mar 2022 16:14:26 -0500	[thread overview]
Message-ID: <20220317211426.38940-1-eajames@linux.ibm.com> (raw)

The data transfer routines must poll the status register to
determine when more data can be shifted in or out. If the hardware
gets into a bad state, these polling loops may never exit. Prevent
this by returning an error if a timeout is exceeded.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
 drivers/spi/spi-fsi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/spi/spi-fsi.c b/drivers/spi/spi-fsi.c
index b6c7467f0b59..d403a7a3021d 100644
--- a/drivers/spi/spi-fsi.c
+++ b/drivers/spi/spi-fsi.c
@@ -25,6 +25,7 @@
 
 #define SPI_FSI_BASE			0x70000
 #define SPI_FSI_INIT_TIMEOUT_MS		1000
+#define SPI_FSI_STATUS_TIMEOUT_MS	100
 #define SPI_FSI_MAX_RX_SIZE		8
 #define SPI_FSI_MAX_TX_SIZE		40
 
@@ -299,6 +300,7 @@ static int fsi_spi_transfer_data(struct fsi_spi *ctx,
 				 struct spi_transfer *transfer)
 {
 	int rc = 0;
+	unsigned long end;
 	u64 status = 0ULL;
 
 	if (transfer->tx_buf) {
@@ -315,10 +317,14 @@ static int fsi_spi_transfer_data(struct fsi_spi *ctx,
 			if (rc)
 				return rc;
 
+			end = jiffies + msecs_to_jiffies(SPI_FSI_STATUS_TIMEOUT_MS);
 			do {
 				rc = fsi_spi_status(ctx, &status, "TX");
 				if (rc)
 					return rc;
+
+				if (time_after(jiffies, end))
+					return -ETIMEDOUT;
 			} while (status & SPI_FSI_STATUS_TDR_FULL);
 
 			sent += nb;
@@ -329,10 +335,14 @@ static int fsi_spi_transfer_data(struct fsi_spi *ctx,
 		u8 *rx = transfer->rx_buf;
 
 		while (transfer->len > recv) {
+			end = jiffies + msecs_to_jiffies(SPI_FSI_STATUS_TIMEOUT_MS);
 			do {
 				rc = fsi_spi_status(ctx, &status, "RX");
 				if (rc)
 					return rc;
+
+				if (time_after(jiffies, end))
+					return -ETIMEDOUT;
 			} while (!(status & SPI_FSI_STATUS_RDR_FULL));
 
 			rc = fsi_spi_read_reg(ctx, SPI_FSI_DATA_RX, &in);
-- 
2.27.0


WARNING: multiple messages have this Message-ID (diff)
From: Eddie James <eajames@linux.ibm.com>
To: linux-spi@vger.kernel.org
Cc: openbmc@lists.ozlabs.org, broonie@kernel.org,
	Eddie James <eajames@linux.ibm.com>,
	linux-kernel@vger.kernel.org, joel@jms.id.au
Subject: [PATCH] spi: fsi: Implement a timeout for polling status
Date: Thu, 17 Mar 2022 16:14:26 -0500	[thread overview]
Message-ID: <20220317211426.38940-1-eajames@linux.ibm.com> (raw)

The data transfer routines must poll the status register to
determine when more data can be shifted in or out. If the hardware
gets into a bad state, these polling loops may never exit. Prevent
this by returning an error if a timeout is exceeded.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
---
 drivers/spi/spi-fsi.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/spi/spi-fsi.c b/drivers/spi/spi-fsi.c
index b6c7467f0b59..d403a7a3021d 100644
--- a/drivers/spi/spi-fsi.c
+++ b/drivers/spi/spi-fsi.c
@@ -25,6 +25,7 @@
 
 #define SPI_FSI_BASE			0x70000
 #define SPI_FSI_INIT_TIMEOUT_MS		1000
+#define SPI_FSI_STATUS_TIMEOUT_MS	100
 #define SPI_FSI_MAX_RX_SIZE		8
 #define SPI_FSI_MAX_TX_SIZE		40
 
@@ -299,6 +300,7 @@ static int fsi_spi_transfer_data(struct fsi_spi *ctx,
 				 struct spi_transfer *transfer)
 {
 	int rc = 0;
+	unsigned long end;
 	u64 status = 0ULL;
 
 	if (transfer->tx_buf) {
@@ -315,10 +317,14 @@ static int fsi_spi_transfer_data(struct fsi_spi *ctx,
 			if (rc)
 				return rc;
 
+			end = jiffies + msecs_to_jiffies(SPI_FSI_STATUS_TIMEOUT_MS);
 			do {
 				rc = fsi_spi_status(ctx, &status, "TX");
 				if (rc)
 					return rc;
+
+				if (time_after(jiffies, end))
+					return -ETIMEDOUT;
 			} while (status & SPI_FSI_STATUS_TDR_FULL);
 
 			sent += nb;
@@ -329,10 +335,14 @@ static int fsi_spi_transfer_data(struct fsi_spi *ctx,
 		u8 *rx = transfer->rx_buf;
 
 		while (transfer->len > recv) {
+			end = jiffies + msecs_to_jiffies(SPI_FSI_STATUS_TIMEOUT_MS);
 			do {
 				rc = fsi_spi_status(ctx, &status, "RX");
 				if (rc)
 					return rc;
+
+				if (time_after(jiffies, end))
+					return -ETIMEDOUT;
 			} while (!(status & SPI_FSI_STATUS_RDR_FULL));
 
 			rc = fsi_spi_read_reg(ctx, SPI_FSI_DATA_RX, &in);
-- 
2.27.0


             reply	other threads:[~2022-03-17 21:14 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-17 21:14 Eddie James [this message]
2022-03-17 21:14 ` [PATCH] spi: fsi: Implement a timeout for polling status Eddie James
2022-03-18  4:19 ` Joel Stanley
2022-03-18  4:19   ` Joel Stanley
2022-03-18 14:10   ` Eddie James
2022-03-18 20:58 ` Mark Brown
2022-03-18 20:58   ` Mark Brown

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=20220317211426.38940-1-eajames@linux.ibm.com \
    --to=eajames@linux.ibm.com \
    --cc=broonie@kernel.org \
    --cc=joel@jms.id.au \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-spi@vger.kernel.org \
    --cc=openbmc@lists.ozlabs.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.