[PATCHv3 0/6] serial: mxs-auart: devm conversion, clock rework, and IRQ ordering fixes

[PATCHv3 0/6] serial: mxs-auart: devm conversion, clock rework, and IRQ ordering fixes

[Rosen Penev]

This series cleans up the mxs-auart driver by converting to devm-managed
resources, fixing clock prepare/enable ordering, and addressing IRQ
registration races.

Patch 1 fixes compilation on 64-bit build with W=1

Patch 2 reworks the clock handling to use devm_clk_get_enabled and
reorders clk_prepare_enable after clk_set_rate to avoid
CLK_SET_RATE_GATE failures.

Patch 3 converts iomem mapping and GPIO IRQ requests to devm,
removing the manual cleanup paths.

Patch 4 moves the main UART IRQ registration after uart_add_one_port
so the port state is initialized before the handler can run, and
manages the module clock for console vs non-console ports correctly.

v3: two more sashiko fixes
v2: split off of_device_get_match_data change.

Rosen Penev (6):
  serial: mxs-auart: fix cast type for of_device_get_match_data
  serial: mxs-auart: rework clock handling in mxs_get_clks and probe
  serial: mxs-auart: use devm resources for iomem and GPIO IRQs
  serial: mxs-auart: fix IRQ registration ordering and manage console
    clock
  serial: mxs-auart: clamp RX DMA count to buffer size
  serial: mxs-auart: terminate DMA before releasing channels in exit

 drivers/tty/serial/mxs-auart.c | 145 +++++++++++++++------------------
 1 file changed, 66 insertions(+), 79 deletions(-)

--
2.54.0

[PATCHv3 1/6] serial: mxs-auart: fix cast type for of_device_get_match_data

[Rosen Penev]

of_device_get_match_data returns const void*. Cast to unsigned long to
avoid implicit integer truncation warnings. All the data parameters are
correct anyway.

Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/tty/serial/mxs-auart.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 697318dbb146..de97c0f74e7d 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1598,7 +1598,7 @@ static int mxs_auart_probe(struct platform_device *pdev)
 		return -EINVAL;
 	}
 
-	s->devtype = (enum mxs_auart_type)of_device_get_match_data(&pdev->dev);
+	s->devtype = (unsigned long)of_device_get_match_data(&pdev->dev);
 
 	ret = mxs_get_clks(s, pdev);
 	if (ret)
-- 
2.54.0

[PATCHv3 2/6] serial: mxs-auart: rework clock handling in mxs_get_clks and probe

[Rosen Penev]

Use devm_clk_get_enabled for the AHB clock so its enable/disable
lifetime is managed by the driver model. Move the mod clock
(clk) prepare_enable out of mxs_get_clks and into probe so that
clk_set_rate is called while the clock is still disabled, avoiding
CLK_SET_RATE_GATE failures. Clean up the error labels accordingly.

Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/tty/serial/mxs-auart.c | 47 ++++++++++++----------------------
 1 file changed, 17 insertions(+), 30 deletions(-)

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index de97c0f74e7d..aa59a48bfad7 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1470,34 +1470,22 @@ static int mxs_get_clks(struct mxs_auart_port *s,
 		return PTR_ERR(s->clk);
 	}
 
-	s->clk_ahb = devm_clk_get(s->dev, "ahb");
+	s->clk_ahb = devm_clk_get_enabled(s->dev, "ahb");
 	if (IS_ERR(s->clk_ahb)) {
 		dev_err(s->dev, "Failed to get \"ahb\" clk\n");
 		return PTR_ERR(s->clk_ahb);
 	}
 
-	err = clk_prepare_enable(s->clk_ahb);
-	if (err) {
-		dev_err(s->dev, "Failed to enable ahb_clk!\n");
-		return err;
-	}
-
+	/*
+	 * Set mod clock rate while it is still disabled so
+	 * CLK_SET_RATE_GATE does not cause clk_set_rate to fail.
+	 * The mod clock will be enabled in mxs_auart_startup()
+	 * and in probe after mxs_get_clks returns.
+	 */
 	err = clk_set_rate(s->clk, clk_get_rate(s->clk_ahb));
-	if (err) {
+	if (err)
 		dev_err(s->dev, "Failed to set rate!\n");
-		goto disable_clk_ahb;
-	}
 
-	err = clk_prepare_enable(s->clk);
-	if (err) {
-		dev_err(s->dev, "Failed to enable clk!\n");
-		goto disable_clk_ahb;
-	}
-
-	return 0;
-
-disable_clk_ahb:
-	clk_disable_unprepare(s->clk_ahb);
 	return err;
 }
 
@@ -1604,17 +1592,21 @@ static int mxs_auart_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
+	ret = clk_prepare_enable(s->clk);
+	if (ret)
+		return ret;
+
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!r) {
 		ret = -ENXIO;
-		goto out_disable_clks;
+		goto out_disable_clk;
 	}
 
 	s->port.mapbase = r->start;
 	s->port.membase = ioremap(r->start, resource_size(r));
 	if (!s->port.membase) {
 		ret = -ENOMEM;
-		goto out_disable_clks;
+		goto out_disable_clk;
 	}
 	s->port.ops = &mxs_auart_ops;
 	s->port.iotype = UPIO_MEM;
@@ -1681,11 +1673,8 @@ static int mxs_auart_probe(struct platform_device *pdev)
 out_iounmap:
 	iounmap(s->port.membase);
 
-out_disable_clks:
-	if (is_asm9260_auart(s)) {
-		clk_disable_unprepare(s->clk);
-		clk_disable_unprepare(s->clk_ahb);
-	}
+out_disable_clk:
+	clk_disable_unprepare(s->clk);
 	return ret;
 }
 
@@ -1697,10 +1686,8 @@ static void mxs_auart_remove(struct platform_device *pdev)
 	auart_port[pdev->id] = NULL;
 	mxs_auart_free_gpio_irq(s);
 	iounmap(s->port.membase);
-	if (is_asm9260_auart(s)) {
+	if (is_asm9260_auart(s))
 		clk_disable_unprepare(s->clk);
-		clk_disable_unprepare(s->clk_ahb);
-	}
 }
 
 static struct platform_driver mxs_auart_driver = {
-- 
2.54.0

[PATCHv3 3/6] serial: mxs-auart: use devm resources for iomem and GPIO IRQs

[Rosen Penev]

Replace platform_get_resource + ioremap with
devm_platform_get_and_ioremap_resource and convert GPIO IRQ
request_irq/free_irq to devm_request_irq. This eliminates the
mxs_auart_free_gpio_irq function and its call sites, and the
out_iounmap error label. Simplify the remove function accordingly.

Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/tty/serial/mxs-auart.c | 53 +++++++---------------------------
 1 file changed, 11 insertions(+), 42 deletions(-)

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index aa59a48bfad7..4499e3206e85 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -1517,15 +1517,6 @@ static int mxs_auart_init_gpios(struct mxs_auart_port *s, struct device *dev)
 	return 0;
 }
 
-static void mxs_auart_free_gpio_irq(struct mxs_auart_port *s)
-{
-	enum mctrl_gpio_idx i;
-
-	for (i = 0; i < UART_GPIO_MAX; i++)
-		if (s->gpio_irq[i] >= 0)
-			free_irq(s->gpio_irq[i], s);
-}
-
 static int mxs_auart_request_gpio_irq(struct mxs_auart_port *s)
 {
 	int *irq = s->gpio_irq;
@@ -1537,21 +1528,13 @@ static int mxs_auart_request_gpio_irq(struct mxs_auart_port *s)
 			continue;
 
 		irq_set_status_flags(irq[i], IRQ_NOAUTOEN);
-		err = request_irq(irq[i], mxs_auart_irq_handle,
-				IRQ_TYPE_EDGE_BOTH, dev_name(s->dev), s);
+		err = devm_request_irq(s->dev, irq[i], mxs_auart_irq_handle,
+				       IRQ_TYPE_EDGE_BOTH, dev_name(s->dev), s);
 		if (err)
 			dev_err(s->dev, "%s - Can't get %d irq\n",
 				__func__, irq[i]);
 	}
 
-	/*
-	 * If something went wrong, rollback.
-	 * Be careful: i may be unsigned.
-	 */
-	while (err && (i-- > 0))
-		if (irq[i] >= 0)
-			free_irq(irq[i], s);
-
 	return err;
 }
 
@@ -1596,18 +1579,12 @@ static int mxs_auart_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
-	if (!r) {
-		ret = -ENXIO;
+	s->port.membase = devm_platform_get_and_ioremap_resource(pdev, 0, &r);
+	if (IS_ERR(s->port.membase)) {
+		ret = PTR_ERR(s->port.membase);
 		goto out_disable_clk;
 	}
-
 	s->port.mapbase = r->start;
-	s->port.membase = ioremap(r->start, resource_size(r));
-	if (!s->port.membase) {
-		ret = -ENOMEM;
-		goto out_disable_clk;
-	}
 	s->port.ops = &mxs_auart_ops;
 	s->port.iotype = UPIO_MEM;
 	s->port.fifosize = MXS_AUART_FIFO_SIZE;
@@ -1622,21 +1599,21 @@ static int mxs_auart_probe(struct platform_device *pdev)
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		ret = irq;
-		goto out_iounmap;
+		goto out_disable_clk;
 	}
 
 	s->port.irq = irq;
 	ret = devm_request_irq(&pdev->dev, irq, mxs_auart_irq_handle, 0,
 			       dev_name(&pdev->dev), s);
 	if (ret)
-		goto out_iounmap;
+		goto out_disable_clk;
 
 	platform_set_drvdata(pdev, s);
 
 	ret = mxs_auart_init_gpios(s, &pdev->dev);
 	if (ret) {
 		dev_err(&pdev->dev, "Failed to initialize GPIOs.\n");
-		goto out_iounmap;
+		goto out_disable_clk;
 	}
 
 	/*
@@ -1644,7 +1621,7 @@ static int mxs_auart_probe(struct platform_device *pdev)
 	 */
 	ret = mxs_auart_request_gpio_irq(s);
 	if (ret)
-		goto out_iounmap;
+		goto out_disable_clk;
 
 	auart_port[s->port.line] = s;
 
@@ -1667,11 +1644,7 @@ static int mxs_auart_probe(struct platform_device *pdev)
 	return 0;
 
 out_free_qpio_irq:
-	mxs_auart_free_gpio_irq(s);
-	auart_port[pdev->id] = NULL;
-
-out_iounmap:
-	iounmap(s->port.membase);
+	auart_port[s->port.line] = NULL;
 
 out_disable_clk:
 	clk_disable_unprepare(s->clk);
@@ -1683,11 +1656,7 @@ static void mxs_auart_remove(struct platform_device *pdev)
 	struct mxs_auart_port *s = platform_get_drvdata(pdev);
 
 	uart_remove_one_port(&auart_driver, &s->port);
-	auart_port[pdev->id] = NULL;
-	mxs_auart_free_gpio_irq(s);
-	iounmap(s->port.membase);
-	if (is_asm9260_auart(s))
-		clk_disable_unprepare(s->clk);
+	auart_port[s->port.line] = NULL;
 }
 
 static struct platform_driver mxs_auart_driver = {
-- 
2.54.0

[PATCHv3 4/6] serial: mxs-auart: fix IRQ registration ordering and manage console clock

[Rosen Penev]

Move the main UART IRQ registration after uart_add_one_port so that
s->port.state and s->port.lock are initialized before the interrupt
handler can run. Mask all UART interrupts before adding the port to
prevent spurious IRQs left by the bootloader.

After probe succeeds, disable the module clock for non-console ports
since startup will re-enable it on port open. For console ports, keep
the clock prepared so auart_console_write() can safely call
clk_enable() from atomic context.

Guard the IRQ handler and get_mctrl with clk_enable/clk_disable since
GPIO IRQs and serial-core status queries can fire while the clock is
disabled for non-console ports.

In remove, disable the clock for console ports to balance the enable
done in probe, preventing a clock leak on unbind.

Assisted-by: opencode:big-pickle
---
 drivers/tty/serial/mxs-auart.c | 49 +++++++++++++++++++++++++++-------
 1 file changed, 39 insertions(+), 10 deletions(-)

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index 4499e3206e85..e2b656638ab3 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -738,9 +738,13 @@ static u32 mxs_auart_modem_status(struct mxs_auart_port *s, u32 mctrl)
 static u32 mxs_auart_get_mctrl(struct uart_port *u)
 {
 	struct mxs_auart_port *s = to_auart_port(u);
-	u32 stat = mxs_read(s, REG_STAT);
+	u32 stat;
 	u32 mctrl = 0;
 
+	clk_enable(s->clk);
+	stat = mxs_read(s, REG_STAT);
+	clk_disable(s->clk);
+
 	if (stat & AUART_STAT_CTS)
 		mctrl |= TIOCM_CTS;
 
@@ -1079,6 +1083,7 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
 	struct mxs_auart_port *s = context;
 	u32 mctrl_temp = s->mctrl_prev;
 
+	clk_enable(s->clk);
 	uart_port_lock(&s->port);
 
 	stat = mxs_read(s, REG_STAT);
@@ -1118,6 +1123,7 @@ static irqreturn_t mxs_auart_irq_handle(int irq, void *context)
 	}
 
 	uart_port_unlock(&s->port);
+	clk_disable(s->clk);
 
 	return IRQ_HANDLED;
 }
@@ -1603,10 +1609,6 @@ static int mxs_auart_probe(struct platform_device *pdev)
 	}
 
 	s->port.irq = irq;
-	ret = devm_request_irq(&pdev->dev, irq, mxs_auart_irq_handle, 0,
-			       dev_name(&pdev->dev), s);
-	if (ret)
-		goto out_disable_clk;
 
 	platform_set_drvdata(pdev, s);
 
@@ -1627,9 +1629,28 @@ static int mxs_auart_probe(struct platform_device *pdev)
 
 	mxs_auart_reset_deassert(s);
 
+	/* Mask all UART interrupts to prevent spurious IRQs from bootloader */
+	mxs_write(0, s, REG_INTR);
+
 	ret = uart_add_one_port(&auart_driver, &s->port);
-	if (ret)
-		goto out_free_qpio_irq;
+	if (ret) {
+		auart_port[s->port.line] = NULL;
+		goto out_disable_clk;
+	}
+
+	/*
+	 * Request the main IRQ after uart_add_one_port so that
+	 * s->port.state and s->port.lock are initialized before
+	 * the handler can run in response to a bootloader-left
+	 * interrupt.
+	 */
+	ret = devm_request_irq(&pdev->dev, irq, mxs_auart_irq_handle, 0,
+			       dev_name(&pdev->dev), s);
+	if (ret) {
+		uart_remove_one_port(&auart_driver, &s->port);
+		auart_port[s->port.line] = NULL;
+		goto out_disable_clk;
+	}
 
 	/* ASM9260 don't have version reg */
 	if (is_asm9260_auart(s)) {
@@ -1641,10 +1662,16 @@ static int mxs_auart_probe(struct platform_device *pdev)
 			 (version >> 16) & 0xff, version & 0xffff);
 	}
 
-	return 0;
+	/*
+	 * Disable clock -- startup will re-enable when the port is opened.
+	 * For the console port the clock must stay prepared so that
+	 * auart_console_write() can safely call clk_enable() from
+	 * atomic context.
+	 */
+	if (!uart_console(&s->port))
+		clk_disable_unprepare(s->clk);
 
-out_free_qpio_irq:
-	auart_port[s->port.line] = NULL;
+	return 0;
 
 out_disable_clk:
 	clk_disable_unprepare(s->clk);
@@ -1657,6 +1684,8 @@ static void mxs_auart_remove(struct platform_device *pdev)
 
 	uart_remove_one_port(&auart_driver, &s->port);
 	auart_port[s->port.line] = NULL;
+	if (uart_console(&s->port))
+		clk_disable_unprepare(s->clk);
 }
 
 static struct platform_driver mxs_auart_driver = {
-- 
2.54.0

[PATCHv3 5/6] serial: mxs-auart: clamp RX DMA count to buffer size

[Rosen Penev]

In dma_rx_callback(), the RX count from the hardware status register
(AUART_STAT_RXCOUNT_MASK = 0xffff) is passed directly to
tty_insert_flip_string() without any bounds check. Since rx_dma_buf
is allocated with UART_XMIT_SIZE (4096 bytes), a hardware fault or
compromised peripheral reporting a count larger than 4096 would cause
an out-of-bounds read, potentially leaking kernel memory.

Clamp the count to UART_XMIT_SIZE before use.

Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/tty/serial/mxs-auart.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index e2b656638ab3..fe48a372d022 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -823,7 +823,7 @@ static void dma_rx_callback(void *arg)
 	stat &= ~(AUART_STAT_OERR | AUART_STAT_BERR |
 			AUART_STAT_PERR | AUART_STAT_FERR);
 
-	count = stat & AUART_STAT_RXCOUNT_MASK;
+	count = min_t(u32, stat & AUART_STAT_RXCOUNT_MASK, UART_XMIT_SIZE);
 	tty_insert_flip_string(port, s->rx_dma_buf, count);
 
 	mxs_write(stat, s, REG_STAT);
-- 
2.54.0

[PATCHv3 6/6] serial: mxs-auart: terminate DMA before releasing channels in exit

[Rosen Penev]

mxs_auart_dma_exit_channel() calls dma_release_channel() and then
kfree() on the DMA buffers without first terminating any in-flight
transfers. If an asynchronous DMA transfer completes after the buffers
have been freed, the callback will access freed memory.

Call dmaengine_terminate_sync() on each channel before releasing it
to safely abort pending transfers.

Assisted-by: opencode:big-pickle
Signed-off-by: Rosen Penev <rosenp@gmail.com>
---
 drivers/tty/serial/mxs-auart.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/tty/serial/mxs-auart.c b/drivers/tty/serial/mxs-auart.c
index fe48a372d022..ec2c60dd0f52 100644
--- a/drivers/tty/serial/mxs-auart.c
+++ b/drivers/tty/serial/mxs-auart.c
@@ -872,10 +872,12 @@ static int mxs_auart_dma_prep_rx(struct mxs_auart_port *s)
 static void mxs_auart_dma_exit_channel(struct mxs_auart_port *s)
 {
 	if (s->tx_dma_chan) {
+		dmaengine_terminate_sync(s->tx_dma_chan);
 		dma_release_channel(s->tx_dma_chan);
 		s->tx_dma_chan = NULL;
 	}
 	if (s->rx_dma_chan) {
+		dmaengine_terminate_sync(s->rx_dma_chan);
 		dma_release_channel(s->rx_dma_chan);
 		s->rx_dma_chan = NULL;
 	}
-- 
2.54.0