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;
 }