[PATCH v2 1/1] serial: 8250_dw: Call dw8250_quirks() conditionally

[Andy Shevchenko]

Not all the cases provide the driver data, that is represented by
an object instance of struct dw8250_platform_data. Id est the change
missed the case when the driver is instantiated via board files as
pure platform driver. Fix this by calling dw8250_quirks() conditionally.
This will require splitting dw8250_setup_dma_filter() out of dw8250_quirks().
Also make sure IRQ handler won't crash, it also requires driver data
to be present.

Fixes: bfd3d4a40f39 ("serial: 8250_dw: Drop unneeded NULL checks in dw8250_quirks()")
Reported-by: kernel test robot <oliver.sang@xxxxxxxxx>
Closes: https://lore.kernel.org/oe-lkp/202502121529.f7e65d49-lkp@xxxxxxxxx
Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
---

v2: made sure IRQ handler won't be called when no driver data provided

Note, there is no Cc: stable@ as the culprit is only in Linux Next.

 drivers/tty/serial/8250/8250_dw.c | 36 ++++++++++++++++++-------------
 1 file changed, 21 insertions(+), 15 deletions(-)

diff --git a/drivers/tty/serial/8250/8250_dw.c b/drivers/tty/serial/8250/8250_dw.c
index ac3987513564..af24ec25d976 100644
--- a/drivers/tty/serial/8250/8250_dw.c
+++ b/drivers/tty/serial/8250/8250_dw.c
@@ -421,6 +421,18 @@ static bool dw8250_idma_filter(struct dma_chan *chan, void *param)
 	return param == chan->device->dev;
 }
 
+static void dw8250_setup_dma_filter(struct uart_port *p, struct dw8250_data *data)
+{
+	/* Platforms with iDMA 64-bit */
+	if (platform_get_resource_byname(to_platform_device(p->dev), IORESOURCE_MEM, "lpss_priv")) {
+		data->data.dma.rx_param = p->dev->parent;
+		data->data.dma.tx_param = p->dev->parent;
+		data->data.dma.fn = dw8250_idma_filter;
+	} else {
+		data->data.dma.fn = dw8250_fallback_dma_filter;
+	}
+}
+
 static u32 dw8250_rzn1_get_dmacr_burst(int max_burst)
 {
 	if (max_burst >= 8)
@@ -491,14 +503,6 @@ static void dw8250_quirks(struct uart_port *p, struct dw8250_data *data)
 		p->serial_in = dw8250_serial_in32;
 		data->uart_16550_compatible = true;
 	}
-
-	/* Platforms with iDMA 64-bit */
-	if (platform_get_resource_byname(to_platform_device(p->dev),
-					 IORESOURCE_MEM, "lpss_priv")) {
-		data->data.dma.rx_param = p->dev->parent;
-		data->data.dma.tx_param = p->dev->parent;
-		data->data.dma.fn = dw8250_idma_filter;
-	}
 }
 
 static void dw8250_reset_control_assert(void *data)
@@ -520,7 +524,6 @@ static int dw8250_probe(struct platform_device *pdev)
 		return dev_err_probe(dev, -EINVAL, "no registers defined\n");
 
 	spin_lock_init(&p->lock);
-	p->handle_irq	= dw8250_handle_irq;
 	p->pm		= dw8250_do_pm;
 	p->type		= PORT_8250;
 	p->flags	= UPF_FIXED_PORT;
@@ -532,13 +535,8 @@ static int dw8250_probe(struct platform_device *pdev)
 	if (!data)
 		return -ENOMEM;
 
-	data->data.dma.fn = dw8250_fallback_dma_filter;
-	data->pdata = device_get_match_data(p->dev);
 	p->private_data = &data->data;
 
-	data->uart_16550_compatible = device_property_read_bool(dev,
-						"snps,uart-16550-compatible");
-
 	p->mapbase = regs->start;
 	p->mapsize = resource_size(regs);
 
@@ -626,11 +624,19 @@ static int dw8250_probe(struct platform_device *pdev)
 	if (err)
 		return err;
 
-	dw8250_quirks(p, data);
+	data->uart_16550_compatible = device_property_read_bool(dev, "snps,uart-16550-compatible");
+
+	data->pdata = device_get_match_data(p->dev);
+	if (data->pdata)
+		dw8250_quirks(p, data);
 
 	/* If the Busy Functionality is not implemented, don't handle it */
 	if (data->uart_16550_compatible)
 		p->handle_irq = NULL;
+	else if (data->pdata)
+		p->handle_irq = dw8250_handle_irq;
+
+	dw8250_setup_dma_filter(p, data);
 
 	if (!data->skip_autocfg)
 		dw8250_setup_port(p);
-- 
2.45.1.3035.g276e886db78b