[U-Boot] [PATCH v3 1/2] serial: Introduce linflex uart support

["Eddy Petrișor" <eddy.petrisor@gmail.com>]

From: Stoica Cosmin-Stefan <cosminstefan.stoica@freescale.com>

The Linflex module is integrated on some NXP automotive SoCs part of the former
Freescale portfolio, like S32V234, an SoC for Advanced Driver Assistance
Systems.

Original-signed-off-by: Stoica Cosmin-Stefan <cosminstefan.stoica@freescale.com>
Original-signed-off-by: Chircu Bogdan <Bogdan.Chircu@freescale.com>
Original-signed-off-by: Depons Eric <eric.depons@freescale.com>
Original-signed-off-by: Eddy Petri?or <eddy.petrisor@gmail.com>

Signed-off-by: Eddy Petri?or <eddy.petrisor@gmail.com>
---

Notes:
    Changes in v2:
    Added support for device model. Compatibility with non-DM code is kept
    for easier synchronization with the code on the vendor branch where the
    conversion to DM is not done for all boards.
    
    Changes in v3:
    Removed non-DM compatibility, as requested.

 drivers/serial/Makefile             |   1 +
 drivers/serial/serial_linflexuart.c | 221 ++++++++++++++++++++++++++++++++++++
 2 files changed, 222 insertions(+)
 create mode 100644 drivers/serial/serial_linflexuart.c

diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 9def128..c45cf5d 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -34,6 +34,7 @@ obj-$(CONFIG_SCIF_CONSOLE) += serial_sh.o
 obj-$(CONFIG_ZYNQ_SERIAL) += serial_zynq.o
 obj-$(CONFIG_BFIN_SERIAL) += serial_bfin.o
 obj-$(CONFIG_FSL_LPUART) += serial_lpuart.o
+obj-$(CONFIG_FSL_LINFLEXUART) += serial_linflexuart.o
 obj-$(CONFIG_ARC_SERIAL) += serial_arc.o
 obj-$(CONFIG_UNIPHIER_SERIAL) += serial_uniphier.o
 obj-$(CONFIG_STM32_SERIAL) += serial_stm32.o
diff --git a/drivers/serial/serial_linflexuart.c b/drivers/serial/serial_linflexuart.c
new file mode 100644
index 0000000..771d0bd
--- /dev/null
+++ b/drivers/serial/serial_linflexuart.c
@@ -0,0 +1,221 @@
+/*
+ * (C) Copyright 2013-2016 Freescale Semiconductor, Inc.
+ *
+ * SPDX-License-Identifier:     GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <watchdog.h>
+#include <asm/io.h>
+#include <serial.h>
+#include <linux/compiler.h>
+#include <asm/arch/imx-regs.h>
+#include <asm/arch/clock.h>
+
+#define US1_TDRE            (1 << 7)
+#define US1_RDRF            (1 << 5)
+#define UC2_TE              (1 << 3)
+#define LINCR1_INIT         (1 << 0)
+#define LINCR1_MME          (1 << 4)
+#define LINCR1_BF           (1 << 7)
+#define LINSR_LINS_INITMODE (0x00001000)
+#define LINSR_LINS_MASK     (0x0000F000)
+#define UARTCR_UART         (1 << 0)
+#define UARTCR_WL0          (1 << 1)
+#define UARTCR_PCE          (1 << 2)
+#define UARTCR_PC0          (1 << 3)
+#define UARTCR_TXEN         (1 << 4)
+#define UARTCR_RXEN         (1 << 5)
+#define UARTCR_PC1          (1 << 6)
+#define UARTSR_DTF          (1 << 1)
+#define UARTSR_DRF          (1 << 2)
+#define UARTSR_RMB          (1 << 9)
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#ifndef CONFIG_DM_SERIAL
+#error "The linflex serial driver does not have non-DM support."
+#endif
+
+static void _linflex_serial_setbrg(struct linflex_fsl *base, int baudrate)
+{
+	u32 clk = mxc_get_clock(MXC_UART_CLK);
+	u32 ibr, fbr;
+
+	if (!baudrate)
+		baudrate = CONFIG_BAUDRATE;
+
+	ibr = (u32) (clk / (16 * gd->baudrate));
+	fbr = (u32) (clk % (16 * gd->baudrate)) * 16;
+
+	__raw_writel(ibr, &base->linibrr);
+	__raw_writel(fbr, &base->linfbrr);
+}
+
+static int _linflex_serial_getc(struct linflex_fsl *base)
+{
+	char c;
+
+	if (!(__raw_readb(&base->uartsr) & UARTSR_DRF))
+		return -EAGAIN;
+
+	if (!(__raw_readl(&base->uartsr) & UARTSR_RMB))
+		return -EAGAIN;
+
+	c = __raw_readl(&base->bdrm);
+	__raw_writeb((__raw_readb(&base->uartsr) | (UARTSR_DRF | UARTSR_RMB)),
+		     &base->uartsr);
+	return c;
+}
+
+static int _linflex_serial_putc(struct linflex_fsl *base, const char c)
+{
+	__raw_writeb(c, &base->bdrl);
+
+
+	if (!(__raw_readb(&base->uartsr) & UARTSR_DTF))
+		return -EAGAIN;
+
+	__raw_writeb((__raw_readb(&base->uartsr) | UARTSR_DTF), &base->uartsr);
+
+	return 0;
+}
+
+/*
+ * Initialise the serial port with the given baudrate. The settings
+ * are always 8 data bits, no parity, 1 stop bit, no start bits.
+ */
+static int _linflex_serial_init(struct linflex_fsl *base)
+{
+	volatile u32 ctrl;
+
+	/* set the Linflex in master mode amd activate by-pass filter */
+	ctrl = LINCR1_BF | LINCR1_MME;
+	__raw_writel(ctrl, &base->lincr1);
+
+	/* init mode */
+	ctrl |= LINCR1_INIT;
+	__raw_writel(ctrl, &base->lincr1);
+
+	/* waiting for init mode entry - TODO: add a timeout */
+	while ((__raw_readl(&base->linsr) & LINSR_LINS_MASK) !=
+	       LINSR_LINS_INITMODE);
+
+	/* set UART bit to allow writing other bits */
+	__raw_writel(UARTCR_UART, &base->uartcr);
+
+	/* provide data bits, parity, stop bit, etc */
+	serial_setbrg();
+
+	/* 8 bit data, no parity, Tx and Rx enabled, UART mode */
+	__raw_writel(UARTCR_PC1 | UARTCR_RXEN | UARTCR_TXEN | UARTCR_PC0
+		     | UARTCR_WL0 | UARTCR_UART, &base->uartcr);
+
+	ctrl = __raw_readl(&base->lincr1);
+	ctrl &= ~LINCR1_INIT;
+	__raw_writel(ctrl, &base->lincr1);	/* end init mode */
+
+	return 0;
+}
+
+struct linflex_serial_platdata {
+	struct linflex_fsl *base_addr;
+	u8 port_id; /* do we need this? */
+};
+
+struct linflex_serial_priv {
+	struct linflex_fsl *lfuart;
+};
+
+int linflex_serial_setbrg(struct udevice *dev, int baudrate)
+{
+	struct linflex_serial_priv *priv = dev_get_priv(dev);
+
+	_linflex_serial_setbrg(priv->lfuart, baudrate);
+
+	return 0;
+}
+
+static int linflex_serial_getc(struct udevice *dev)
+{
+	struct linflex_serial_priv *priv = dev_get_priv(dev);
+
+	return _linflex_serial_getc(priv->lfuart);
+}
+
+static int linflex_serial_putc(struct udevice *dev, const char ch)
+{
+
+	struct linflex_serial_priv *priv = dev_get_priv(dev);
+
+	return _linflex_serial_putc(priv->lfuart, ch);
+}
+
+static int linflex_serial_pending(struct udevice *dev, bool input)
+{
+	struct linflex_serial_priv *priv = dev_get_priv(dev);
+	uint32_t uartsr = __raw_readl(&priv->lfuart->uartsr);
+
+	if (input)
+		return ((uartsr & UARTSR_DRF) && (uartsr & UARTSR_RMB)) ? 1 : 0;
+	else
+		return uartsr & UARTSR_DTF ? 0 : 1;
+}
+
+static void linflex_serial_init_internal(struct linflex_fsl *lfuart)
+{
+	_linflex_serial_init(lfuart);
+	_linflex_serial_setbrg(lfuart, CONFIG_BAUDRATE);
+	return;
+}
+
+static int linflex_serial_probe(struct udevice *dev)
+{
+	struct linflex_serial_platdata *plat = dev->platdata;
+	struct linflex_serial_priv *priv = dev_get_priv(dev);
+
+	priv->lfuart = (struct linflex_fsl *)plat->base_addr;
+	linflex_serial_init_internal(priv->lfuart);
+
+	return 0;
+}
+
+static const struct dm_serial_ops linflex_serial_ops = {
+	.putc = linflex_serial_putc,
+	.pending = linflex_serial_pending,
+	.getc = linflex_serial_getc,
+	.setbrg = linflex_serial_setbrg,
+};
+
+U_BOOT_DRIVER(serial_linflex) = {
+	.name	= "serial_linflex",
+	.id	= UCLASS_SERIAL,
+	.probe = linflex_serial_probe,
+	.ops	= &linflex_serial_ops,
+	.flags = DM_FLAG_PRE_RELOC,
+	.priv_auto_alloc_size	= sizeof(struct linflex_serial_priv),
+};
+
+#ifdef CONFIG_DEBUG_UART_LINFLEXUART
+
+#include <debug_uart.h>
+
+
+static inline void _debUG_uart_init(void)
+{
+	struct linflex_fsl *base = (struct linflex_fsl *)CONFIG_DEBUG_UART_BASE;
+
+	linflex_serial_init_internal(base);
+}
+
+static inline void _debug_uart_putc(int ch)
+{
+	struct linflex_fsl *base = (struct linflex_fsl *)CONFIG_DEBUG_UART_BASE;
+
+	/* XXX: Is this OK? Should this use the non-DM version? */
+	_linflex_serial_putc(base, ch);
+}
+
+#endif /* CONFIG_DEBUG_UART_LINFLEXUART */
-- 
2.5.0