commit 895a7866c20cf6c01779b5a60fbf2770b88930a4
author Michal Simek <michal.simek@xilinx.com> Tue Mar 24 11:31:42 2020 +0100
committer Michal Simek <michal.simek@xilinx.com> Mon Apr 06 12:52:45 2020 +0200
tree 289bd3a5ab6f82236f30fc4a5cda932dee6a912a
parent 5028358a6a5c3e7fd2d20b190a4205ba3e136ab8

serial: zynq: Change uart initialization logic

The commit a673025535ae ("serial: zynq: Initialize uart only before
relocation") introduced code which detects relocation which is working for
single uart instance. With multiple instances in place there is a need to
enable and setup every instance. That's why detect if TX is enabled. If it
is then don't initialize uart again.
In post probe setbrg is called to setup baudrate but values should be the
same.

As a side effect of this change is that DECLARE_GLOBAL_DATA_PTR can be
removed completely.

Signed-off-by: Michal Simek <michal.simek@xilinx.com>

drivers/serial/serial_zynq.c

diff --git a/drivers/serial/serial_zynq.c b/drivers/serial/serial_zynq.c
index e4e4c39..0dd6cec 100644
--- a/drivers/serial/serial_zynq.c
+++ b/drivers/serial/serial_zynq.c
@@ -17,8 +17,6 @@
 #include <serial.h>
 #include <linux/err.h>
 
-DECLARE_GLOBAL_DATA_PTR;
-
 #define ZYNQ_UART_SR_TXACTIVE	BIT(11) /* TX active */
 #define ZYNQ_UART_SR_TXFULL	BIT(4) /* TX FIFO full */
 #define ZYNQ_UART_SR_RXEMPTY	BIT(1) /* RX FIFO empty */
@@ -45,7 +43,7 @@
 	struct uart_zynq *regs;
 };
 
-/* Set up the baud rate in gd struct */
+/* Set up the baud rate */
 static void _uart_zynq_serial_setbrg(struct uart_zynq *regs,
 				     unsigned long clock, unsigned long baud)
 {
@@ -140,9 +138,12 @@
 static int zynq_serial_probe(struct udevice *dev)
 {
 	struct zynq_uart_platdata *platdata = dev_get_platdata(dev);
+	struct uart_zynq *regs = platdata->regs;
+	u32 val;
 
-	/* No need to reinitialize the UART after relocation */
-	if (gd->flags & GD_FLG_RELOC)
+	/* No need to reinitialize the UART if TX already enabled */
+	val = readl(&regs->control);
+	if (val & ZYNQ_UART_CR_TX_EN)
 		return 0;
 
 	_uart_zynq_serial_init(platdata->regs);