From 4e36c0f20cb1c74c7bd7ea31ba432c1c4a989031 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Sun, 7 Jul 2024 10:28:46 +0200 Subject: [PATCH 1/3] i2c: rcar: bring hardware to known state when probing When probing, the hardware is not brought into a known state. This may be a problem when a hypervisor restarts Linux without resetting the hardware, leaving an old state running. Make sure the hardware gets initialized, especially interrupts should be cleared and disabled. Reported-by: Dirk Behme Reported-by: Geert Uytterhoeven Closes: https://lore.kernel.org/r/20240702045535.2000393-1-dirk.behme@de.bosch.com Fixes: 6ccbe607132b ("i2c: add Renesas R-Car I2C driver") Signed-off-by: Wolfram Sang Signed-off-by: Andi Shyti --- drivers/i2c/busses/i2c-rcar.c | 17 ++++++++++++----- 1 file changed, 12 insertions(+), 5 deletions(-) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index 828aa2ea0fe4..ec73463ea9b5 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -257,6 +257,14 @@ static void rcar_i2c_init(struct rcar_i2c_priv *priv) } } +static void rcar_i2c_reset_slave(struct rcar_i2c_priv *priv) +{ + rcar_i2c_write(priv, ICSIER, 0); + rcar_i2c_write(priv, ICSSR, 0); + rcar_i2c_write(priv, ICSCR, SDBS); + rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */ +} + static int rcar_i2c_bus_barrier(struct rcar_i2c_priv *priv) { int ret; @@ -1033,11 +1041,8 @@ static int rcar_unreg_slave(struct i2c_client *slave) /* ensure no irq is running before clearing ptr */ disable_irq(priv->irq); - rcar_i2c_write(priv, ICSIER, 0); - rcar_i2c_write(priv, ICSSR, 0); + rcar_i2c_reset_slave(priv); enable_irq(priv->irq); - rcar_i2c_write(priv, ICSCR, SDBS); - rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */ priv->slave = NULL; @@ -1152,7 +1157,9 @@ static int rcar_i2c_probe(struct platform_device *pdev) goto out_pm_disable; } - rcar_i2c_write(priv, ICSAR, 0); /* Gen2: must be 0 if not using slave */ + /* Bring hardware to known state */ + rcar_i2c_init(priv); + rcar_i2c_reset_slave(priv); if (priv->devtype < I2C_RCAR_GEN3) { irqflags |= IRQF_NO_THREAD; From fea6b5ebb71a2830b042e42de7ae255017ac3ce8 Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Wed, 10 Jul 2024 13:03:00 +0200 Subject: [PATCH 2/3] i2c: rcar: clear NO_RXDMA flag after resetting We should allow RXDMA only if the reset was really successful, so clear the flag after the reset call. Fixes: 0e864b552b23 ("i2c: rcar: reset controller is mandatory for Gen3+") Signed-off-by: Wolfram Sang Signed-off-by: Andi Shyti --- drivers/i2c/busses/i2c-rcar.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index ec73463ea9b5..f0724c8e4b21 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -911,10 +911,10 @@ static int rcar_i2c_master_xfer(struct i2c_adapter *adap, /* Gen3+ needs a reset. That also allows RXDMA once */ if (priv->devtype >= I2C_RCAR_GEN3) { - priv->flags &= ~ID_P_NO_RXDMA; ret = rcar_i2c_do_reset(priv); if (ret) goto out; + priv->flags &= ~ID_P_NO_RXDMA; } rcar_i2c_init(priv); From ea5ea84c9d3570dc06e8fc5ee2273eaa584aa3ac Mon Sep 17 00:00:00 2001 From: Wolfram Sang Date: Thu, 11 Jul 2024 10:30:44 +0200 Subject: [PATCH 3/3] i2c: rcar: ensure Gen3+ reset does not disturb local targets R-Car Gen3+ needs a reset before every controller transfer. That erases configuration of a potentially in parallel running local target instance. To avoid this disruption, avoid controller transfers if a local target is running. Also, disable SMBusHostNotify because it requires being a controller and local target at the same time. Fixes: 3b770017b03a ("i2c: rcar: handle RXDMA HW behaviour on Gen3") Signed-off-by: Wolfram Sang Signed-off-by: Andi Shyti --- drivers/i2c/busses/i2c-rcar.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/i2c/busses/i2c-rcar.c b/drivers/i2c/busses/i2c-rcar.c index f0724c8e4b21..185a5d60f101 100644 --- a/drivers/i2c/busses/i2c-rcar.c +++ b/drivers/i2c/busses/i2c-rcar.c @@ -883,6 +883,10 @@ static int rcar_i2c_do_reset(struct rcar_i2c_priv *priv) { int ret; + /* Don't reset if a slave instance is currently running */ + if (priv->slave) + return -EISCONN; + ret = reset_control_reset(priv->rstc); if (ret) return ret; @@ -1175,6 +1179,7 @@ static int rcar_i2c_probe(struct platform_device *pdev) if (of_property_read_bool(dev->of_node, "smbus")) priv->flags |= ID_P_HOST_NOTIFY; + /* R-Car Gen3+ needs a reset before every transfer */ if (priv->devtype >= I2C_RCAR_GEN3) { priv->rstc = devm_reset_control_get_exclusive(&pdev->dev, NULL); if (IS_ERR(priv->rstc)) { @@ -1185,6 +1190,9 @@ static int rcar_i2c_probe(struct platform_device *pdev) ret = reset_control_status(priv->rstc); if (ret < 0) goto out_pm_put; + + /* hard reset disturbs HostNotify local target, so disable it */ + priv->flags &= ~ID_P_HOST_NOTIFY; } ret = platform_get_irq(pdev, 0);