serial: xilinx_uartps: read reg size from DTS

Current implementation uses `CDNS_UART_REGISTER_SPACE(0x1000)`
for request_mem_region() and ioremap() in cdns_uart_request_port() API.

The cadence/xilinx IP has register space defined from offset 0x0 to 0x48.
It also mentions that the register map is defined as [6:0]. So, the upper
region may/maynot be used based on the IP integration.

In Axiado AX3000 SoC two UART instances are defined
0x100 apart. That is creating issue in some other instance due to overlap
with addresses.

Since, this address space is already being defined in the
devicetree, use the same when requesting the register space.

Fixes: 1f70557 ("arm64: dts: axiado: Add initial support for AX3000 SoC and eval board")
Acked-by: Michal Simek <[email protected]>
Signed-off-by: Harshit Shah <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: hshahaxiado

drivers/tty/serial/xilinx_uartps.c

@@ -33,7 +33,6 @@
 #define CDNS_UART_MINOR		0	/* works best with devtmpfs */
 #define CDNS_UART_NR_PORTS	16
 #define CDNS_UART_FIFO_SIZE	64	/* FIFO size */
-#define CDNS_UART_REGISTER_SPACE	0x1000
 #define TX_TIMEOUT		500000
 
 /* Rx Trigger level */
@@ -1098,15 +1097,15 @@ static int cdns_uart_verify_port(struct uart_port *port,
  */
 static int cdns_uart_request_port(struct uart_port *port)
 {
-	if (!request_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE,
+	if (!request_mem_region(port->mapbase, port->mapsize,
 					 CDNS_UART_NAME)) {
 		return -ENOMEM;
 	}
 
-	port->membase = ioremap(port->mapbase, CDNS_UART_REGISTER_SPACE);
+	port->membase = ioremap(port->mapbase, port->mapsize);
 	if (!port->membase) {
 		dev_err(port->dev, "Unable to map registers\n");
-		release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE);
+		release_mem_region(port->mapbase, port->mapsize);
 		return -ENOMEM;
 	}
 	return 0;
@@ -1121,7 +1120,7 @@ static int cdns_uart_request_port(struct uart_port *port)
  */
 static void cdns_uart_release_port(struct uart_port *port)
 {
-	release_mem_region(port->mapbase, CDNS_UART_REGISTER_SPACE);
+	release_mem_region(port->mapbase, port->mapsize);
 	iounmap(port->membase);
 	port->membase = NULL;
 }
@@ -1780,6 +1779,7 @@ static int cdns_uart_probe(struct platform_device *pdev)
 	 * and triggers invocation of the config_port() entry point.
 	 */
 	port->mapbase = res->start;
+	port->mapsize = resource_size(res);
 	port->irq = irq;
 	port->dev = &pdev->dev;
 	port->uartclk = clk_get_rate(cdns_uart_data->uartclk);