target/linux/ath79/patches-5.4/0060-serial-ar933x_uart-set-UART_CS_-RX-TX-_READY_ORIDE.patch

   1 From patchwork Fri Feb  7 09:53:35 2020
   2 Content-Type: text/plain; charset="utf-8"
   3 MIME-Version: 1.0
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   5 X-Patchwork-Submitter: Daniel Golle <daniel@makrotopia.org>
   6 X-Patchwork-Id: 1190470
   7 Date: Fri, 7 Feb 2020 11:53:35 +0200
   8 From: Daniel Golle <daniel@makrotopia.org>
   9 To: linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org
  10 Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
  11         Jiri Slaby <jslaby@suse.com>,
  12         Chuanhong Guo <gch981213@gmail.com>,
  13         Eitan Cohen <eitan@neot-semadar.com>,
  14         Ori Gofen <origofen@gmail.com>
  15 Subject: [PATCH] serial: ar933x_uart: set UART_CS_{RX,TX}_READY_ORIDE
  16 Message-ID: <20200207095335.GA179836@makrotopia.org>
  17 MIME-Version: 1.0
  18 Content-Disposition: inline
  19 Sender: linux-kernel-owner@vger.kernel.org
  20 Precedence: bulk
  21 List-ID: <linux-kernel.vger.kernel.org>
  22 X-Mailing-List: linux-kernel@vger.kernel.org
  23
  24 On AR934x this UART is usually not initialized by the bootloader
  25 as it is only used as a secondary serial port while the primary
  26 UART is a newly introduced NS16550-compatible.
  27 In order to make use of the ar933x-uart on AR934x without RTS/CTS
  28 hardware flow control, one needs to set the
  29 UART_CS_{RX,TX}_READY_ORIDE bits as other than on AR933x where this
  30 UART is used as primary/console, the bootloader on AR934x typically
  31 doesn't set those bits.
  32 Setting them explicitely on AR933x should not do any harm, so just
  33 set them unconditionally.
  34
  35 Tested-by: Chuanhong Guo <gch981213@gmail.com>
  36 Signed-off-by: Daniel Golle <daniel@makrotopia.org>
  37 ---
  38  drivers/tty/serial/ar933x_uart.c | 8 ++++++++
  39  1 file changed, 8 insertions(+)
  40
  41 --- a/drivers/tty/serial/ar933x_uart.c
  42 +++ b/drivers/tty/serial/ar933x_uart.c
  43 @@ -290,6 +290,10 @@ static void ar933x_uart_set_termios(stru
  44         ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
  45                 AR933X_UART_CS_TX_READY_ORIDE | AR933X_UART_CS_RX_READY_ORIDE);
  46
  47 +       /* enable RX and TX ready overide */
  48 +       ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
  49 +               AR933X_UART_CS_TX_READY_ORIDE | AR933X_UART_CS_RX_READY_ORIDE);
  50 +
  51         /* reenable the UART */
  52         ar933x_uart_rmw(up, AR933X_UART_CS_REG,
  53                         AR933X_UART_CS_IF_MODE_M << AR933X_UART_CS_IF_MODE_S,
  54 @@ -424,6 +428,10 @@ static int ar933x_uart_startup(struct ua
  55
  56         /* enable RX and TX ready overide */
  57         ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
  58 +               AR933X_UART_CS_TX_READY_ORIDE | AR933X_UART_CS_RX_READY_ORIDE);
  59 +
  60 +       /* enable RX and TX ready overide */
  61 +       ar933x_uart_rmw_set(up, AR933X_UART_CS_REG,
  62                 AR933X_UART_CS_TX_READY_ORIDE | AR933X_UART_CS_RX_READY_ORIDE);
  63
  64         /* Enable RX interrupts */