ARC: [arcfpga] Early ARC UART to be only activated by cmdline

Earlier CONFIG_SERIAL_ARC_CONSOLE would unconditionally enable the
legacy ARC UART based early console even if platform lacked that UART
(e.g. nSIM OSCI platform).

So a multi-platform image containing the 2 UART drivers won't work.

Fix that by probing the driver only if "earlyprintk=ttyARC0" is present
in cmdline.

Reported-by: Chuck Jordan <cjordan@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>

1 files changed, 4 insertions, 9 deletions

diff --git a/arch/arc/plat-arcfpga/platform.c b/arch/arc/plat-arcfpga/platform.c
index f09e771b4bbd..61c7e5997387 100644
--- a/arch/arc/plat-arcfpga/platform.c
+++ b/arch/arc/plat-arcfpga/platform.c
@@ -79,16 +79,11 @@ static void arc_fpga_serial_init(void)
                                    ARRAY_SIZE(fpga_early_devs));
 
         /*
-         * ARC console driver registers itself as an early platform driver
-         * of class "earlyprintk".
-         * Install it here, followed by probe of devices.
-         * The installation here doesn't require earlyprintk in command line
-         * To do so however, replace the lines below with
-         *      parse_early_param();
-         *      early_platform_driver_probe("earlyprintk", 1, 1);
-         *                                                    ^^
+         * ARC console driver registers (build time) as an early platform driver
+         * of class "earlyprintk". However it needs explicit cmdline toggle
+         * "earlyprintk=ttyARC0" to be successfuly runtime registered.
+         * Otherwise the early probe below fails to find the driver
          */
-        early_platform_driver_register_all("earlyprintk");
         early_platform_driver_probe("earlyprintk", 1, 0);
 
         /*