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authorAndreas Wass <Andreas.Wass@dalelven.com>2013-08-14 23:45:03 +0200
committerStefano Babic <sbabic@denx.de>2013-08-21 19:20:28 +0200
commit661edaafd44c6a7001a95d3a93a7dc03acc18a39 (patch)
tree0da277c05e38dd1a930c33e9e14eaba64323d823 /drivers/serial/mxs_auart.c
parent8907c2c50408b39e93fb42b2d74ab908480320a0 (diff)
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ARM: mxs: Added application UART driver
The driver makes it possible to use an application UART as the U-Boot output console for Freescale i.MX23/i.MX28 devices. Signed-off-by: Andreas Wass <andreas.wass@dalelven.com> Cc: Fabio Estevam <fabio.estevam@freescale.com> Cc: Marek Vasut <marex@denx.de> Acked-by: Marek Vasut <marex@denx.de>
Diffstat (limited to 'drivers/serial/mxs_auart.c')
-rw-r--r--drivers/serial/mxs_auart.c151
1 files changed, 151 insertions, 0 deletions
diff --git a/drivers/serial/mxs_auart.c b/drivers/serial/mxs_auart.c
new file mode 100644
index 0000000..7cfe5bc
--- /dev/null
+++ b/drivers/serial/mxs_auart.c
@@ -0,0 +1,151 @@
+/*
+ * Freescale i.MX23/i.MX28 AUART driver
+ *
+ * Copyright (C) 2013 Andreas Wass <andreas.wass@dalelven.com>
+ *
+ * Based on the MXC serial driver:
+ *
+ * (c) 2007 Sascha Hauer <s.hauer@pengutronix.de>
+ *
+ * Further based on the Linux mxs-auart.c driver:
+ *
+ * Freescale STMP37XX/STMP38X Application UART drkiver
+ * Copyright 2008-2010 Freescale Semiconductor, Inc.
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+#include <common.h>
+#include <asm/io.h>
+#include <serial.h>
+#include <linux/compiler.h>
+#include <asm/arch/regs-base.h>
+#include <asm/arch/regs-uartapp.h>
+#include <asm/arch/sys_proto.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+#ifndef CONFIG_MXS_AUART_BASE
+#error "CONFIG_MXS_AUART_BASE must be set to the base UART to use"
+#endif
+
+/* AUART clock always supplied by XTAL and always 24MHz */
+#define MXS_AUART_CLK 24000000
+
+static struct mxs_uartapp_regs *get_uartapp_registers(void)
+{
+ return (struct mxs_uartapp_regs *)CONFIG_MXS_AUART_BASE;
+}
+
+/**
+ * Sets the baud rate and settings.
+ * The settings are: 8 data bits, no parit and 1 stop bit.
+ */
+void mxs_auart_setbrg(void)
+{
+ u32 div;
+ u32 linectrl = 0;
+ struct mxs_uartapp_regs *regs = get_uartapp_registers();
+
+ if (!gd->baudrate)
+ gd->baudrate = CONFIG_BAUDRATE;
+
+ /*
+ * From i.MX28 datasheet:
+ * div is calculated by calculating UARTCLK*32/baudrate, rounded to int
+ * div must be between 0xEC and 0x003FFFC0 inclusive
+ * Lowest 6 bits of div goes in BAUD_DIVFRAC part of LINECTRL register
+ * Next 16 bits goes in BAUD_DIVINT part of LINECTRL register
+ */
+ div = (MXS_AUART_CLK * 32) / gd->baudrate;
+ if (div < 0xEC || div > 0x003FFFC0)
+ return;
+
+ linectrl |= ((div & UARTAPP_LINECTRL_EXTRACT_BAUD_DIVFRAC_MASK) <<
+ UARTAPP_LINECTRL_BAUD_DIVFRAC_OFFSET) &
+ UARTAPP_LINECTRL_BAUD_DIVFRAC_MASK;
+ linectrl |= ((div >> UARTAPP_LINECTRL_EXTRACT_BAUD_DIVINT_OFFSET) <<
+ UARTAPP_LINECTRL_BAUD_DIVINT_OFFSET) &
+ UARTAPP_LINECTRL_BAUD_DIVINT_MASK;
+
+ /* Word length: 8 bits */
+ linectrl |= UARTAPP_LINECTRL_WLEN_8BITS;
+
+ /* Enable FIFOs. */
+ linectrl |= UARTAPP_LINECTRL_FEN_MASK;
+
+ /* Write above settings, no parity, 1 stop bit */
+ writel(linectrl, &regs->hw_uartapp_linectrl);
+}
+
+int mxs_auart_init(void)
+{
+ struct mxs_uartapp_regs *regs = get_uartapp_registers();
+ /* Reset everything */
+ mxs_reset_block(&regs->hw_uartapp_ctrl0_reg);
+ /* Disable interrupts */
+ writel(0, &regs->hw_uartapp_intr);
+ /* Set baud rate and settings */
+ serial_setbrg();
+ /* Disable RTS and CTS, ignore LINECTRL2 register */
+ writel(UARTAPP_CTRL2_RTSEN_MASK |
+ UARTAPP_CTRL2_CTSEN_MASK |
+ UARTAPP_CTRL2_USE_LCR2_MASK,
+ &regs->hw_uartapp_ctrl2_clr);
+ /* Enable receiver, transmitter and UART */
+ writel(UARTAPP_CTRL2_RXE_MASK |
+ UARTAPP_CTRL2_TXE_MASK |
+ UARTAPP_CTRL2_UARTEN_MASK,
+ &regs->hw_uartapp_ctrl2_set);
+ return 0;
+}
+
+void mxs_auart_putc(const char c)
+{
+ struct mxs_uartapp_regs *regs = get_uartapp_registers();
+ /* Wait in loop while the transmit FIFO is full */
+ while (readl(&regs->hw_uartapp_stat) & UARTAPP_STAT_TXFF_MASK)
+ ;
+
+ writel(c, &regs->hw_uartapp_data);
+
+ if (c == '\n')
+ mxs_auart_putc('\r');
+}
+
+int mxs_auart_tstc(void)
+{
+ struct mxs_uartapp_regs *regs = get_uartapp_registers();
+ /* Checks if receive FIFO is empty */
+ return !(readl(&regs->hw_uartapp_stat) & UARTAPP_STAT_RXFE_MASK);
+}
+
+int mxs_auart_getc(void)
+{
+ struct mxs_uartapp_regs *regs = get_uartapp_registers();
+ /* Wait until a character is available to read */
+ while (!mxs_auart_tstc())
+ ;
+ /* Read the character from the data register */
+ return readl(&regs->hw_uartapp_data) & 0xFF;
+}
+
+static struct serial_device mxs_auart_drv = {
+ .name = "mxs_auart_serial",
+ .start = mxs_auart_init,
+ .stop = NULL,
+ .setbrg = mxs_auart_setbrg,
+ .putc = mxs_auart_putc,
+ .puts = default_serial_puts,
+ .getc = mxs_auart_getc,
+ .tstc = mxs_auart_tstc,
+};
+
+void mxs_auart_initialize(void)
+{
+ serial_register(&mxs_auart_drv);
+}
+
+__weak struct serial_device *default_serial_console(void)
+{
+ return &mxs_auart_drv;
+}