[PATCH] serial: zynq: Change uart initialization logic

[PATCH] serial: zynq: Change uart initialization logic

[Michal Simek]

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 | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/drivers/serial/serial_zynq.c b/drivers/serial/serial_zynq.c
index e4e4c3928582..0dd6cec82a65 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 zynq_uart_platdata {
 	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_setbrg(struct udevice *dev, int baudrate)
 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);
-- 
2.25.1

[PATCH] serial: zynq: Change uart initialization logic

[Michal Simek]

?t 24. 3. 2020 v 12:24 odes?latel Michal Simek <michal.simek@xilinx.com> napsal:
>
> 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 | 11 ++++++-----
>  1 file changed, 6 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/serial/serial_zynq.c b/drivers/serial/serial_zynq.c
> index e4e4c3928582..0dd6cec82a65 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 zynq_uart_platdata {
>         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_setbrg(struct udevice *dev, int baudrate)
>  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);
> --
> 2.25.1
>

Applied.
M

-- 
Michal Simek, Ing. (M.Eng), OpenPGP -> KeyID: FE3D1F91
w: www.monstr.eu p: +42-0-721842854
Maintainer of Linux kernel - Xilinx Microblaze
Maintainer of Linux kernel - Xilinx Zynq ARM and ZynqMP ARM64 SoCs
U-Boot custodian - Xilinx Microblaze/Zynq/ZynqMP/Versal SoCs