The RPi3 typically uses the regular UART for high-speed communication with
the Bluetooth device, leaving us the mini UART to use for the serial
console. Add support for this UART so we can use it.
Signed-off-by: Stephen Warren <swar...@wwwdotorg.org>
---
v2: Add clock and skip_init fields to platform data.
---
drivers/serial/Makefile | 1 +
drivers/serial/serial_bcm283x_mu.c | 140 +++++++++++++++++++++++++++
include/dm/platform_data/serial_bcm283x_mu.h | 24 +++++
3 files changed, 165 insertions(+)
create mode 100644 drivers/serial/serial_bcm283x_mu.c
create mode 100644 include/dm/platform_data/serial_bcm283x_mu.h
diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
index 05bdf56c6fe9..ee7147a77abc 100644
--- a/drivers/serial/Makefile
+++ b/drivers/serial/Makefile
@@ -38,6 +38,7 @@ obj-$(CONFIG_UNIPHIER_SERIAL) += serial_uniphier.o
obj-$(CONFIG_STM32_SERIAL) += serial_stm32.o
obj-$(CONFIG_PIC32_SERIAL) += serial_pic32.o
obj-$(CONFIG_STM32X7_SERIAL) += serial_stm32x7.o
+obj-$(CONFIG_BCM283X_MU_SERIAL) += serial_bcm283x_mu.o
ifndef CONFIG_SPL_BUILD
obj-$(CONFIG_USB_TTY) += usbtty.o
diff --git a/drivers/serial/serial_bcm283x_mu.c
b/drivers/serial/serial_bcm283x_mu.c
new file mode 100644
index 000000000000..fc36bc0e85d6
--- /dev/null
+++ b/drivers/serial/serial_bcm283x_mu.c
@@ -0,0 +1,140 @@
+/*
+ * (C) Copyright 2016 Stephen Warren <swar...@wwwdotorg.org>
+ *
+ * Derived from pl01x code:
+ *
+ * (C) Copyright 2000
+ * Rob Taylor, Flying Pig Systems. r...@flyingpig.com.
+ *
+ * (C) Copyright 2004
+ * ARM Ltd.
+ * Philippe Robin, <philippe.ro...@arm.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+/* Simple U-Boot driver for the BCM283x mini UART */
+
+#include <common.h>
+#include <dm.h>
+#include <errno.h>
+#include <watchdog.h>
+#include <asm/io.h>
+#include <serial.h>
+#include <dm/platform_data/serial_bcm283x_mu.h>
+#include <linux/compiler.h>
+#include <fdtdec.h>
+
+struct bcm283x_mu_regs {
+ u32 io;
+ u32 iir;
+ u32 ier;
+ u32 lcr;
+ u32 mcr;
+ u32 lsr;
+ u32 msr;
+ u32 scratch;
+ u32 cntl;
+ u32 stat;
+ u32 baud;
+};
+
+#define BCM283X_MU_LCR_DATA_SIZE_8 3
+
+#define BCM283X_MU_LSR_TX_IDLE BIT(6)
+/* This actually means not full, but is named not empty in the docs */
+#define BCM283X_MU_LSR_TX_EMPTY BIT(5)
+#define BCM283X_MU_LSR_RX_READY BIT(0)
+
+struct bcm283x_mu_priv {
+ struct bcm283x_mu_regs *regs;
+};
+
+static int bcm283x_mu_serial_setbrg(struct udevice *dev, int baudrate)
+{
+ struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
+ struct bcm283x_mu_priv *priv = dev_get_priv(dev);
+ struct bcm283x_mu_regs *regs = priv->regs;
+ u32 divider;
+
+ if (plat->skip_init)
+ return 0;
+
+ divider = plat->clock / (baudrate * 8);
+
+ writel(BCM283X_MU_LCR_DATA_SIZE_8, ®s->lcr);
+ writel(divider - 1, ®s->baud);
+
+ return 0;
+}
+
+static int bcm283x_mu_serial_probe(struct udevice *dev)
+{
+ struct bcm283x_mu_serial_platdata *plat = dev_get_platdata(dev);
+ struct bcm283x_mu_priv *priv = dev_get_priv(dev);
+
+ priv->regs = (struct bcm283x_mu_regs *)plat->base;
+
+ return 0;
+}
+
+static int bcm283x_mu_serial_getc(struct udevice *dev)
+{
+ struct bcm283x_mu_priv *priv = dev_get_priv(dev);
+ struct bcm283x_mu_regs *regs = priv->regs;
+ u32 data;
+
+ /* Wait until there is data in the FIFO */
+ if (!(readl(®s->lsr) & BCM283X_MU_LSR_RX_READY))
+ return -EAGAIN;
+
+ data = readl(®s->io);
+
+ return (int)data;
+}
+
+static int bcm283x_mu_serial_putc(struct udevice *dev, const char data)
+{
+ struct bcm283x_mu_priv *priv = dev_get_priv(dev);
+ struct bcm283x_mu_regs *regs = priv->regs;
+
+ /* Wait until there is space in the FIFO */
+ if (!(readl(®s->lsr) & BCM283X_MU_LSR_TX_EMPTY))
+ return -EAGAIN;
+
+ /* Send the character */
+ writel(data, ®s->io);
+
+ return 0;
+}
+
+static int bcm283x_mu_serial_pending(struct udevice *dev, bool input)
+{
+ struct bcm283x_mu_priv *priv = dev_get_priv(dev);
+ struct bcm283x_mu_regs *regs = priv->regs;
+ unsigned int lsr = readl(®s->lsr);
+
+ if (input) {
+ WATCHDOG_RESET();
+ return lsr & BCM283X_MU_LSR_RX_READY;
+ } else {
+ return !(lsr & BCM283X_MU_LSR_TX_IDLE);
+ }
+}
+
+static const struct dm_serial_ops bcm283x_mu_serial_ops = {
+ .putc = bcm283x_mu_serial_putc,
+ .pending = bcm283x_mu_serial_pending,
+ .getc = bcm283x_mu_serial_getc,
+ .setbrg = bcm283x_mu_serial_setbrg,
+};
+
+U_BOOT_DRIVER(serial_bcm283x_mu) = {
+ .name = "serial_bcm283x_mu",
+ .id = UCLASS_SERIAL,
+ .platdata_auto_alloc_size = sizeof(struct bcm283x_mu_serial_platdata),
+ .probe = bcm283x_mu_serial_probe,
+ .ops = &bcm283x_mu_serial_ops,
+ .flags = DM_FLAG_PRE_RELOC,
+ .priv_auto_alloc_size = sizeof(struct bcm283x_mu_priv),
+};
diff --git a/include/dm/platform_data/serial_bcm283x_mu.h
b/include/dm/platform_data/serial_bcm283x_mu.h
new file mode 100644
index 000000000000..57ae6adc0538
--- /dev/null
+++ b/include/dm/platform_data/serial_bcm283x_mu.h
@@ -0,0 +1,24 @@
+/*
+ * (C) Copyright 2016 Stephen Warren <swar...@wwwdotorg.org>
+ *
+ * Derived from pl01x code:
+ * Copyright (c) 2014 Google, Inc
+ *
+ * SPDX-License-Identifier: GPL-2.0+
+ */
+
+#ifndef __serial_bcm283x_mu_h
+#define __serial_bcm283x_mu_h
+
+/*
+ *Information about a serial port
+ *
+ * @base: Register base address
+ */
+struct bcm283x_mu_serial_platdata {
+ unsigned long base;
+ unsigned int clock;
+ bool skip_init;
+};
+
+#endif
--
2.7.3
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