This is a note to let you know that I've just added the patch titled
can: flexcan: fix transition from and to low power mode in chip_{en,dis}able
to the 3.13-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
can-flexcan-fix-transition-from-and-to-low-power-mode-in-chip_-en-dis-able.patch
and it can be found in the queue-3.13 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 9b00b300e7bce032c467c36ca47fe2a776887fc2 Mon Sep 17 00:00:00 2001
From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Date: Fri, 28 Feb 2014 15:30:18 +0100
Subject: can: flexcan: fix transition from and to low power mode in chip_{en,dis}able
From: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
commit 9b00b300e7bce032c467c36ca47fe2a776887fc2 upstream.
In flexcan_chip_enable() and flexcan_chip_disable() fixed delays are used.
Experiments have shown that the transition from and to low power mode may take
several microseconds.
This patch adds a while loop which polls the Low Power Mode ACK bit (LPM_ACK)
that indicates a successfull mode change. If the function runs into a timeout a
error value is returned.
Signed-off-by: Marc Kleine-Budde <mkl@xxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/can/flexcan.c | 50 ++++++++++++++++++++++++++++++++++------------
1 file changed, 38 insertions(+), 12 deletions(-)
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -144,6 +144,8 @@
#define FLEXCAN_MB_CODE_MASK (0xf0ffffff)
+#define FLEXCAN_TIMEOUT_US (50)
+
/*
* FLEXCAN hardware feature flags
*
@@ -266,26 +268,42 @@ static inline int flexcan_has_and_handle
(reg_esr & FLEXCAN_ESR_ERR_BUS);
}
-static inline void flexcan_chip_enable(struct flexcan_priv *priv)
+static int flexcan_chip_enable(struct flexcan_priv *priv)
{
struct flexcan_regs __iomem *regs = priv->base;
+ unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;
u32 reg;
reg = flexcan_read(®s->mcr);
reg &= ~FLEXCAN_MCR_MDIS;
flexcan_write(reg, ®s->mcr);
- udelay(10);
+ while (timeout-- && (flexcan_read(®s->mcr) & FLEXCAN_MCR_LPM_ACK))
+ usleep_range(10, 20);
+
+ if (flexcan_read(®s->mcr) & FLEXCAN_MCR_LPM_ACK)
+ return -ETIMEDOUT;
+
+ return 0;
}
-static inline void flexcan_chip_disable(struct flexcan_priv *priv)
+static int flexcan_chip_disable(struct flexcan_priv *priv)
{
struct flexcan_regs __iomem *regs = priv->base;
+ unsigned int timeout = FLEXCAN_TIMEOUT_US / 10;
u32 reg;
reg = flexcan_read(®s->mcr);
reg |= FLEXCAN_MCR_MDIS;
flexcan_write(reg, ®s->mcr);
+
+ while (timeout-- && !(flexcan_read(®s->mcr) & FLEXCAN_MCR_LPM_ACK))
+ usleep_range(10, 20);
+
+ if (!(flexcan_read(®s->mcr) & FLEXCAN_MCR_LPM_ACK))
+ return -ETIMEDOUT;
+
+ return 0;
}
static int flexcan_get_berr_counter(const struct net_device *dev,
@@ -706,7 +724,9 @@ static int flexcan_chip_start(struct net
u32 reg_mcr, reg_ctrl;
/* enable module */
- flexcan_chip_enable(priv);
+ err = flexcan_chip_enable(priv);
+ if (err)
+ return err;
/* soft reset */
flexcan_write(FLEXCAN_MCR_SOFTRST, ®s->mcr);
@@ -946,12 +966,16 @@ static int register_flexcandev(struct ne
goto out_disable_ipg;
/* select "bus clock", chip must be disabled */
- flexcan_chip_disable(priv);
+ err = flexcan_chip_disable(priv);
+ if (err)
+ goto out_disable_per;
reg = flexcan_read(®s->ctrl);
reg |= FLEXCAN_CTRL_CLK_SRC;
flexcan_write(reg, ®s->ctrl);
- flexcan_chip_enable(priv);
+ err = flexcan_chip_enable(priv);
+ if (err)
+ goto out_chip_disable;
/* set freeze, halt and activate FIFO, restrict register access */
reg = flexcan_read(®s->mcr);
@@ -968,14 +992,15 @@ static int register_flexcandev(struct ne
if (!(reg & FLEXCAN_MCR_FEN)) {
netdev_err(dev, "Could not enable RX FIFO, unsupported core\n");
err = -ENODEV;
- goto out_disable_per;
+ goto out_chip_disable;
}
err = register_candev(dev);
- out_disable_per:
/* disable core and turn off clocks */
+ out_chip_disable:
flexcan_chip_disable(priv);
+ out_disable_per:
clk_disable_unprepare(priv->clk_per);
out_disable_ipg:
clk_disable_unprepare(priv->clk_ipg);
@@ -1118,8 +1143,11 @@ static int flexcan_suspend(struct device
{
struct net_device *dev = dev_get_drvdata(device);
struct flexcan_priv *priv = netdev_priv(dev);
+ int err;
- flexcan_chip_disable(priv);
+ err = flexcan_chip_disable(priv);
+ if (err)
+ return err;
if (netif_running(dev)) {
netif_stop_queue(dev);
@@ -1140,9 +1168,7 @@ static int flexcan_resume(struct device
netif_device_attach(dev);
netif_start_queue(dev);
}
- flexcan_chip_enable(priv);
-
- return 0;
+ return flexcan_chip_enable(priv);
}
#endif /* CONFIG_PM_SLEEP */
Patches currently in stable-queue which might be from mkl@xxxxxxxxxxxxxx are
queue-3.13/can-flexcan-fix-transition-from-and-to-low-power-mode-in-chip_-en-dis-able.patch
queue-3.13/can-flexcan-fix-shutdown-first-disable-chip-then-all-interrupts.patch
queue-3.13/can-flexcan-flexcan_remove-add-missing-netif_napi_del.patch
queue-3.13/can-flexcan-factor-out-transceiver-en-dis-able-into-seperate-functions.patch
queue-3.13/can-flexcan-flexcan_open-fix-error-path-if-flexcan_chip_start-fails.patch
--
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