ARC: [plat-arcfpga]: Enabling DeviceTree for Angel4 board

* arc-uart platform device now populated dynamically, using
  of_platform_populate() - applies to any other device whatsoever.

* uart in turn requires incore arc-intc to be also present in DT

* A irq-domain needs to be instantiated for IRQ requests by DT probed
  device (e.g. arc-uart)

TODO: switch over to linear irq domain once all devs have been
      transitioned to DT

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Arnd Bergmann <arnd@arndb.de>

1 files changed, 46 insertions, 51 deletions

diff --git a/arch/arc/plat-arcfpga/platform.c b/arch/arc/plat-arcfpga/platform.c
index 5388b31e2ead..33bcac8bd6b8 100644
--- a/arch/arc/plat-arcfpga/platform.c
+++ b/arch/arc/plat-arcfpga/platform.c
@@ -13,6 +13,7 @@
 #include <linux/device.h>
 #include <linux/platform_device.h>
 #include <linux/console.h>
+#include <linux/of_platform.h>
 #include <asm/setup.h>
 #include <asm/irq.h>
 #include <asm/clk.h>
@@ -20,58 +21,56 @@
 
 /*----------------------- Platform Devices -----------------------------*/
 
-#if defined(CONFIG_SERIAL_ARC) || defined(CONFIG_SERIAL_ARC_MODULE)
-
 static unsigned long arc_uart_info[] = {
-	CONFIG_ARC_SERIAL_BAUD,	/* uart->baud */
-	-1,			/* uart->port.uartclk */
-	-1,			/* uart->is_emulated (runtime @running_on_hw) */
+	0,	/* uart->is_emulated (runtime @running_on_hw) */
+	0,	/* uart->port.uartclk */
+	0,	/* uart->baud */
 	0
 };
 
-#define ARC_UART_DEV(n)					\
-							\
-static struct resource arc_uart##n##_res[] = {		\
-	{						\
-		.start = UART##n##_BASE,			\
-		.end   = UART##n##_BASE + 0xFF,		\
-		.flags = IORESOURCE_MEM,		\
-	},						\
-	{						\
-		.start = UART##n##_IRQ,			\
-		.end   = UART##n##_IRQ,			\
-		.flags = IORESOURCE_IRQ,		\
-	},						\
-};							\
-							\
-static struct platform_device arc_uart##n##_dev = {	\
-	.name = "arc-uart",				\
-	.id = n,					\
-	.num_resources = ARRAY_SIZE(arc_uart##n##_res),	\
-	.resource = arc_uart##n##_res,			\
-	.dev = {					\
-		.platform_data = &arc_uart_info,	\
-	},						\
-}
+#if defined(CONFIG_SERIAL_ARC_CONSOLE)
+/*
+ * static platform data - but only for early serial
+ * TBD: derive this from a special DT node
+ */
+static struct resource arc_uart0_res[] = {
+	{
+		.start = UART0_BASE,
+		.end   = UART0_BASE + 0xFF,
+		.flags = IORESOURCE_MEM,
+	},
+	{
+		.start = UART0_IRQ,
+		.end   = UART0_IRQ,
+		.flags = IORESOURCE_IRQ,
+	},
+};
 
-ARC_UART_DEV(0);
-#if CONFIG_SERIAL_ARC_NR_PORTS > 1
-ARC_UART_DEV(1);
-#endif
+static struct platform_device arc_uart0_dev = {
+	.name = "arc-uart",
+	.id = 0,
+	.num_resources = ARRAY_SIZE(arc_uart0_res),
+	.resource = arc_uart0_res,
+	.dev = {
+		.platform_data = &arc_uart_info,
+	},
+};
 
 static struct platform_device *fpga_early_devs[] __initdata = {
-#if defined(CONFIG_SERIAL_ARC_CONSOLE)
 	&arc_uart0_dev,
-#endif
 };
+#endif
 
 static void arc_fpga_serial_init(void)
 {
+	/* To let driver workaround ISS bug: baudh Reg can't be set to 0 */
+	arc_uart_info[0] = !running_on_hw;
+
 	arc_uart_info[1] = arc_get_core_freq();
 
-	/* To let driver workaround ISS bug: baudh Reg can't be set to 0 */
-	arc_uart_info[2] = !running_on_hw;
+	arc_uart_info[2] = CONFIG_ARC_SERIAL_BAUD;
 
+#if defined(CONFIG_SERIAL_ARC_CONSOLE)
 	early_platform_add_devices(fpga_early_devs,
 				   ARRAY_SIZE(fpga_early_devs));
 
@@ -97,16 +96,9 @@ static void arc_fpga_serial_init(void)
 	 * otherwise the early console never gets a chance to run.
 	 */
 	add_preferred_console("ttyARC", 0, "115200");
+#endif
 }
 
-#else
-
-static void arc_fpga_serial_init(void)
-{
-}
-
-#endif	/* CONFIG_SERIAL_ARC */
-
 /*
  * Early Platform Initialization called from setup_arch()
  */
@@ -117,20 +109,23 @@ void __init arc_platform_early_init(void)
 	arc_fpga_serial_init();
 }
 
-static struct platform_device *fpga_devs[] __initdata = {
+static struct of_dev_auxdata plat_auxdata_lookup[] __initdata = {
 #if defined(CONFIG_SERIAL_ARC) || defined(CONFIG_SERIAL_ARC_MODULE)
-	&arc_uart0_dev,
-#if CONFIG_SERIAL_ARC_NR_PORTS > 1
-	&arc_uart1_dev,
-#endif
+	OF_DEV_AUXDATA("snps,arc-uart", UART0_BASE, "arc-uart", arc_uart_info),
 #endif
+	{}
 };
 
 int __init fpga_plat_init(void)
 {
 	pr_info("[plat-arcfpga]: registering device resources\n");
 
-	platform_add_devices(fpga_devs, ARRAY_SIZE(fpga_devs));
+	/*
+	 * Traverses flattened DeviceTree - registering platform devices
+	 * complete with their resources
+	 */
+	of_platform_populate(NULL, of_default_bus_match_table,
+			     plat_auxdata_lookup, NULL);
 
 	return 0;
 }