openwrt/target/linux/layerscape/patches-5.4/819-uart-0008-MLK-21445-serial-fsl_lpuart-do-HW-reset-for-communic.patch
Yangbo Lu cddd459140 layerscape: add patches-5.4
Add patches for linux-5.4. The patches are from NXP LSDK-20.04 release
which was tagged LSDK-20.04-V5.4.
https://source.codeaurora.org/external/qoriq/qoriq-components/linux/

For boards LS1021A-IOT, and Traverse-LS1043 which are not involved in
LSDK, port the dts patches from 4.14.

The patches are sorted into the following categories:
  301-arch-xxxx
  302-dts-xxxx
  303-core-xxxx
  701-net-xxxx
  801-audio-xxxx
  802-can-xxxx
  803-clock-xxxx
  804-crypto-xxxx
  805-display-xxxx
  806-dma-xxxx
  807-gpio-xxxx
  808-i2c-xxxx
  809-jailhouse-xxxx
  810-keys-xxxx
  811-kvm-xxxx
  812-pcie-xxxx
  813-pm-xxxx
  814-qe-xxxx
  815-sata-xxxx
  816-sdhc-xxxx
  817-spi-xxxx
  818-thermal-xxxx
  819-uart-xxxx
  820-usb-xxxx
  821-vfio-xxxx

Signed-off-by: Yangbo Lu <yangbo.lu@nxp.com>
2020-05-07 12:53:06 +02:00

128 lines
3.8 KiB
Diff

From d9d113c22c634219cc248a7c6dcf157e2927edad Mon Sep 17 00:00:00 2001
From: Fugang Duan <fugang.duan@nxp.com>
Date: Tue, 23 Jul 2019 11:36:22 +0800
Subject: [PATCH] MLK-21445 serial: fsl_lpuart: do HW reset for communication
port
Do HW reset for communication port after the port is registered
if the UART controller support the feature.
Do partition reset with LPUART's power on, LPUART registers will
keep the previous status, like on i.MX8QM platform, which is not
expected action, so reset the HW is required.
Currently, only i.MX7ULP and i.MX8QM LPUART controllers include
global register that support HW reset.
Tested-by: Robin Gong <yibin.gong@nxp.com>
Tested-by: Peng Fan <peng.fan@nxp.com>
Reviewed-by: Robby Cai <robby.cai@nxp.com>
Signed-off-by: Fugang Duan <fugang.duan@nxp.com>
(cherry picked from commit c2bc1f62ec28981462c9cb5ceac17134931ca19f)
Signed-off-by: Arulpandiyan Vadivel <arulpandiyan_vadivel@mentor.com>
Signed-off-by: Shrikant Bobade <Shrikant_Bobade@mentor.com>
(cherry picked from commit 9f396f540093402317c3c1b9a8fe955b91c89164)
---
drivers/tty/serial/fsl_lpuart.c | 48 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 48 insertions(+)
--- a/drivers/tty/serial/fsl_lpuart.c
+++ b/drivers/tty/serial/fsl_lpuart.c
@@ -11,6 +11,7 @@
#include <linux/clk.h>
#include <linux/console.h>
+#include <linux/delay.h>
#include <linux/dma-mapping.h>
#include <linux/dmaengine.h>
#include <linux/dmapool.h>
@@ -116,6 +117,11 @@
#define UARTSFIFO_TXOF 0x02
#define UARTSFIFO_RXUF 0x01
+/* 32-bit global registers only for i.MX7ulp/MX8x
+ * The driver only use the reset feature to reset HW.
+ */
+#define UART_GLOBAL 0x8
+
/* 32-bit register definition */
#define UARTBAUD 0x00
#define UARTSTAT 0x04
@@ -230,6 +236,10 @@
#define UARTWATER_TXWATER_OFF 0
#define UARTWATER_RXWATER_OFF 16
+#define UART_GLOBAL_RST 0x2
+#define RST_HW_MIN_US 20
+#define RST_HW_MAX_US 40
+
#define UARTFIFO_RXIDEN_RDRF 0x3
#define UARTCTRL_IDLECFG 0x7
@@ -335,6 +345,11 @@ MODULE_DEVICE_TABLE(of, lpuart_dt_ids);
static void lpuart_dma_tx_complete(void *arg);
static int lpuart_sched_rx_dma(struct lpuart_port *sport);
+static inline bool is_imx7ulp_lpuart(struct lpuart_port *sport)
+{
+ return sport->devtype == IMX7ULP_LPUART;
+}
+
static inline bool is_imx8qxp_lpuart(struct lpuart_port *sport)
{
return sport->devtype == IMX8QXP_LPUART;
@@ -398,6 +413,33 @@ static unsigned int lpuart_get_baud_clk_
#define lpuart_enable_clks(x) __lpuart_enable_clks(x, true)
#define lpuart_disable_clks(x) __lpuart_enable_clks(x, false)
+static int lpuart_hw_reset(struct lpuart_port *sport)
+{
+ struct uart_port *port = &sport->port;
+ void __iomem *global_addr;
+ int ret;
+
+ if (uart_console(port))
+ return 0;
+
+ ret = clk_prepare_enable(sport->ipg_clk);
+ if (ret) {
+ dev_err(sport->port.dev, "failed to enable uart ipg clk: %d\n", ret);
+ return ret;
+ }
+
+ if (is_imx7ulp_lpuart(sport) || is_imx8qxp_lpuart(sport)) {
+ global_addr = port->membase + UART_GLOBAL - IMX_REG_OFF;
+ writel(UART_GLOBAL_RST, global_addr);
+ usleep_range(RST_HW_MIN_US, RST_HW_MAX_US);
+ writel(0, global_addr);
+ usleep_range(RST_HW_MIN_US, RST_HW_MAX_US);
+ }
+
+ clk_disable_unprepare(sport->ipg_clk);
+ return 0;
+}
+
static void lpuart_stop_tx(struct uart_port *port)
{
unsigned char temp;
@@ -2704,6 +2746,10 @@ static int lpuart_probe(struct platform_
if (ret)
goto failed_attach_port;
+ ret = lpuart_hw_reset(sport);
+ if (ret)
+ goto failed_reset;
+
uart_get_rs485_mode(&pdev->dev, &sport->port.rs485);
if (sport->port.rs485.flags & SER_RS485_RX_DURING_TX)
@@ -2727,6 +2773,8 @@ static int lpuart_probe(struct platform_
return 0;
+failed_reset:
+ uart_remove_one_port(&lpuart_reg, &sport->port);
failed_attach_port:
failed_irq_request:
lpuart_disable_clks(sport);