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i2c: rcar: protect against supurious interrupts on V3U

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V3U creates spurious interrupts which we need to handle. This costs time
until BUS_PHASE_DATA can be activated which is problematic for Gen2 SoCs
and earlier. Because of this we introduce two interrupt handlers here
which will call a generic main irq function once the timing critical
stuff is done.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
This commit is contained in:
Wolfram Sang 2020-12-23 18:21:54 +01:00 committed by Wolfram Sang
parent 24c6d4bc56
commit 9c975c432b
1 changed files with 43 additions and 14 deletions
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57
drivers/i2c/busses/i2c-rcar.c
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@ -625,20 +625,11 @@ static bool rcar_i2c_slave_irq(struct rcar_i2c_priv *priv)
* generated. It turned out that taking a spinlock at the beginning of the ISR
* was already causing repeated messages. Thus, this driver was converted to
* the now lockless behaviour. Please keep this in mind when hacking the driver.
* R-Car Gen3 seems to have this fixed but earlier versions than R-Car Gen2 are
* likely affected. Therefore, we have different interrupt handler entries.
*/
static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
static irqreturn_t rcar_i2c_irq(int irq, struct rcar_i2c_priv *priv, u32 msr)
{
struct rcar_i2c_priv *priv = ptr;
u32 msr;
/* Clear START or STOP immediately, except for REPSTART after read */
if (likely(!(priv->flags & ID_P_REP_AFTER_RD)))
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
msr = rcar_i2c_read(priv, ICMSR);
/* Only handle interrupts that are currently enabled */
msr &= rcar_i2c_read(priv, ICMIER);
if (!msr) {
if (rcar_i2c_slave_irq(priv))
return IRQ_HANDLED;
@ -682,6 +673,41 @@ static irqreturn_t rcar_i2c_irq(int irq, void *ptr)
return IRQ_HANDLED;
}
static irqreturn_t rcar_i2c_gen2_irq(int irq, void *ptr)
{
struct rcar_i2c_priv *priv = ptr;
u32 msr;
/* Clear START or STOP immediately, except for REPSTART after read */
if (likely(!(priv->flags & ID_P_REP_AFTER_RD)))
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
/* Only handle interrupts that are currently enabled */
msr = rcar_i2c_read(priv, ICMSR);
msr &= rcar_i2c_read(priv, ICMIER);
return rcar_i2c_irq(irq, priv, msr);
}
static irqreturn_t rcar_i2c_gen3_irq(int irq, void *ptr)
{
struct rcar_i2c_priv *priv = ptr;
u32 msr;
/* Only handle interrupts that are currently enabled */
msr = rcar_i2c_read(priv, ICMSR);
msr &= rcar_i2c_read(priv, ICMIER);
/*
* Clear START or STOP immediately, except for REPSTART after read or
* if a spurious interrupt was detected.
*/
if (likely(!(priv->flags & ID_P_REP_AFTER_RD) && msr))
rcar_i2c_write(priv, ICMCR, RCAR_BUS_PHASE_DATA);
return rcar_i2c_irq(irq, priv, msr);
}
static struct dma_chan *rcar_i2c_request_dma_chan(struct device *dev,
enum dma_transfer_direction dir,
dma_addr_t port_addr)
@ -929,6 +955,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
struct i2c_adapter *adap;
struct device *dev = &pdev->dev;
unsigned long irqflags = 0;
irqreturn_t (*irqhandler)(int irq, void *ptr) = rcar_i2c_gen3_irq;
int ret;
/* Otherwise logic will break because some bytes must always use PIO */
@ -977,8 +1004,10 @@ static int rcar_i2c_probe(struct platform_device *pdev)
rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */
if (priv->devtype < I2C_RCAR_GEN3)
if (priv->devtype < I2C_RCAR_GEN3) {
irqflags |= IRQF_NO_THREAD;
irqhandler = rcar_i2c_gen2_irq;
}
if (priv->devtype == I2C_RCAR_GEN3) {
priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL);
@ -999,7 +1028,7 @@ static int rcar_i2c_probe(struct platform_device *pdev)
priv->flags |= ID_P_HOST_NOTIFY;
priv->irq = platform_get_irq(pdev, 0);
ret = devm_request_irq(dev, priv->irq, rcar_i2c_irq, irqflags, dev_name(dev), priv);
ret = devm_request_irq(dev, priv->irq, irqhandler, irqflags, dev_name(dev), priv);
if (ret < 0) {
dev_err(dev, "cannot get irq %d\n", priv->irq);
goto out_pm_disable;