8250_men_mcb: Make UART config auto configurable

The UART ports created by this driver were not usable out of
the box, so let the configuration be handled by the 8250 UART
subsystem. This makes the implementation simpler and the UART
port more usable.

The 8250 UART subsystem will take care of requesting the memory
resources, but the driver needs to first read the register where
the num ports is set, so a request of the resource is needed
before registering the UART port.

Co-developed-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
Signed-off-by: Jorge Sanjuan Garcia <jorge.sanjuangarcia@duagon.com>
Signed-off-by: Javier Rodriguez <josejavier.rodriguez@duagon.com>
Link: https://lore.kernel.org/r/20230705131423.30552-4-josejavier.rodriguez@duagon.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 24 insertions, 19 deletions

diff --git a/drivers/tty/serial/8250/8250_men_mcb.c b/drivers/tty/serial/8250/8250_men_mcb.c
index d6cfebb3ee8f..c3143ffddea0 100644
--- a/drivers/tty/serial/8250/8250_men_mcb.c
+++ b/drivers/tty/serial/8250/8250_men_mcb.c
@@ -81,15 +81,28 @@ static u32 men_lookup_uartclk(struct mcb_device *mdev)
 	return clkval;
 }
 
-static int read_uarts_available_from_register(void __iomem *membase,
+static int read_uarts_available_from_register(struct resource *mem_res,
 					      u8 *uarts_available)
 {
 	void __iomem *mem;
 	int reg_value;
 
-	mem = membase + MEN_Z025_REGISTER_OFFSET;
+	if (!request_mem_region(mem_res->start + MEN_Z025_REGISTER_OFFSET,
+				MEM_UART_REGISTER_SIZE,  KBUILD_MODNAME)) {
+		return -EBUSY;
+	}
+
+	mem = ioremap(mem_res->start + MEN_Z025_REGISTER_OFFSET,
+		      MEM_UART_REGISTER_SIZE);
+	if (IS_ERR(mem))
+		return -ENOMEM;
+
+	reg_value = MEN_READ_REGISTER(mem);
+
+	iounmap(mem);
 
-	reg_value = MEN_READ_REGISTER(membase);
+	release_mem_region(mem_res->start + MEN_Z025_REGISTER_OFFSET,
+			   MEM_UART_REGISTER_SIZE);
 
 	*uarts_available = reg_value >> 4;
 
@@ -97,7 +110,7 @@ static int read_uarts_available_from_register(void __iomem *membase,
 }
 
 static int read_serial_data(struct mcb_device *mdev,
-			    void __iomem *membase,
+			    struct resource *mem_res,
 			    struct serial_8250_men_mcb_data *serial_data)
 {
 	u8 uarts_available;
@@ -106,7 +119,7 @@ static int read_serial_data(struct mcb_device *mdev,
 	int res;
 	int i;
 
-	res = read_uarts_available_from_register(membase, &uarts_available);
+	res = read_uarts_available_from_register(mem_res, &uarts_available);
 	if (res < 0)
 		return res;
 
@@ -146,7 +159,7 @@ static int read_serial_data(struct mcb_device *mdev,
 }
 
 static int init_serial_data(struct mcb_device *mdev,
-			    void __iomem *membase,
+			    struct resource *mem_res,
 			    struct serial_8250_men_mcb_data *serial_data)
 {
 	switch (mdev->id) {
@@ -156,7 +169,7 @@ static int init_serial_data(struct mcb_device *mdev,
 		return 0;
 	case MEN_UART_ID_Z025:
 	case MEN_UART_ID_Z057:
-		return read_serial_data(mdev, membase, serial_data);
+		return read_serial_data(mdev, mem_res, serial_data);
 	default:
 		dev_err(&mdev->dev, "no supported device!\n");
 		return -ENODEV;
@@ -170,15 +183,11 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
 	struct serial_8250_men_mcb_data *data;
 	struct resource *mem;
 	int i;
-	void __iomem *membase;
 	int res;
 
 	mem = mcb_get_resource(mdev, IORESOURCE_MEM);
 	if (mem == NULL)
 		return -ENXIO;
-	membase = devm_ioremap_resource(&mdev->dev, mem);
-	if (IS_ERR(membase))
-		return PTR_ERR_OR_ZERO(membase);
 
 	data = devm_kzalloc(&mdev->dev,
 			    sizeof(struct serial_8250_men_mcb_data),
@@ -186,7 +195,7 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
 	if (!data)
 		return -ENOMEM;
 
-	res = init_serial_data(mdev, membase, data);
+	res = init_serial_data(mdev, mem, data);
 	if (res < 0)
 		return res;
 
@@ -196,22 +205,18 @@ static int serial_8250_men_mcb_probe(struct mcb_device *mdev,
 	mcb_set_drvdata(mdev, data);
 
 	for (i = 0; i < data->num_ports; i++) {
-		uart.port.dev = mdev->dma_dev;
+		memset(&uart, 0, sizeof(struct uart_8250_port));
 		spin_lock_init(&uart.port.lock);
 
-		uart.port.type = PORT_16550;
 		uart.port.flags = UPF_SKIP_TEST |
 				  UPF_SHARE_IRQ |
-				  UPF_FIXED_TYPE;
+				  UPF_BOOT_AUTOCONF |
+				  UPF_IOREMAP;
 		uart.port.iotype = UPIO_MEM;
 		uart.port.uartclk = men_lookup_uartclk(mdev);
-		uart.port.regshift = 0;
 		uart.port.irq = mcb_get_irq(mdev);
-		uart.port.membase = membase;
-		uart.port.fifosize = 60;
 		uart.port.mapbase = (unsigned long) mem->start
 					    + data->offset[i];
-		uart.port.iobase = uart.port.mapbase;
 
 		/* ok, register the port */
 		data->line[i] = serial8250_register_8250_port(&uart);