[PATCH v2 10/14] serial: pic32_uart: Add PIC32 UART driver

From: Joshua Henderson
Date: Mon Dec 14 2015 - 17:40:10 EST

From: Andrei Pistirica <andrei.pistirica@xxxxxxxxxxxxx>

This adds UART and a serial console driver for Microchip PIC32 class
devices.

Signed-off-by: Andrei Pistirica <andrei.pistirica@xxxxxxxxxxxxx>
Signed-off-by: Joshua Henderson <joshua.henderson@xxxxxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
---
drivers/tty/serial/Kconfig | 21 +
drivers/tty/serial/Makefile | 1 +
drivers/tty/serial/pic32_uart.c | 927 ++++++++++++++++++++++++++++++++++++++
drivers/tty/serial/pic32_uart.h | 198 ++++++++
include/uapi/linux/serial_core.h | 3 +
5 files changed, 1150 insertions(+)
create mode 100644 drivers/tty/serial/pic32_uart.c
create mode 100644 drivers/tty/serial/pic32_uart.h

diff --git a/drivers/tty/serial/Kconfig b/drivers/tty/serial/Kconfig
index f38beb2..8853b1e 100644
--- a/drivers/tty/serial/Kconfig
+++ b/drivers/tty/serial/Kconfig
@@ -901,6 +901,27 @@ config SERIAL_SGI_L1_CONSOLE
controller serial port as your console (you want this!),
say Y. Otherwise, say N.

+config SERIAL_PIC32
+ tristate "Microchip PIC32 serial support"
+ depends on MACH_PIC32
+ select SERIAL_CORE
+ help
+ If you have a PIC32, this driver supports the serial ports.
+
+ Say Y or M to use PIC32 serial ports, otherwise say N. Note that
+ to use a serial port as a console, this must be included in kernel and
+ not as a module.
+
+config SERIAL_PIC32_CONSOLE
+ bool "PIC32 serial console support"
+ depends on SERIAL_PIC32
+ select SERIAL_CORE_CONSOLE
+ help
+ If you have a PIC32, this driver supports the putting a console on one
+ of the serial ports.
+
+ Say Y to use the PIC32 console, otherwise say N.
+
config SERIAL_MPC52xx
tristate "Freescale MPC52xx/MPC512x family PSC serial support"
depends on PPC_MPC52xx || PPC_MPC512x
diff --git a/drivers/tty/serial/Makefile b/drivers/tty/serial/Makefile
index 5ab4111..bc5e354 100644
--- a/drivers/tty/serial/Makefile
+++ b/drivers/tty/serial/Makefile
@@ -93,6 +93,7 @@ obj-$(CONFIG_SERIAL_CONEXANT_DIGICOLOR) += digicolor-usart.o
obj-$(CONFIG_SERIAL_MEN_Z135) += men_z135_uart.o
obj-$(CONFIG_SERIAL_SPRD) += sprd_serial.o
obj-$(CONFIG_SERIAL_STM32) += stm32-usart.o
+obj-$(CONFIG_SERIAL_PIC32) += pic32_uart.o

# GPIOLIB helpers for modem control lines
obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o
diff --git a/drivers/tty/serial/pic32_uart.c b/drivers/tty/serial/pic32_uart.c
new file mode 100644
index 0000000..5c05c11
--- /dev/null
+++ b/drivers/tty/serial/pic32_uart.c
@@ -0,0 +1,927 @@
+/*
+ * PIC32 Integrated Serial Driver.
+ *
+ * Copyright (C) 2015 Microchip Technology, Inc.
+ *
+ * Authors:
+ * Steve Scott <steve.scott@xxxxxxxxxxxxx>,
+ * Sorin-Andrei Pistirica <andrei.pistirica@xxxxxxxxxxxxx>
+ *
+ * Licensed under GPLv2 or later.
+ */
+
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/of_irq.h>
+#include <linux/of_gpio.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/console.h>
+#include <linux/clk-provider.h>
+#include <linux/clk.h>
+#include <linux/clkdev.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/sysrq.h>
+#include <linux/serial.h>
+#include <linux/serial_core.h>
+#include <uapi/linux/serial_core.h>
+#include <linux/delay.h>
+
+#include "pic32_uart.h"
+
+/* UART name and device definitions */
+#define PIC32_DEV_NAME "pic32-uart"
+#define PIC32_MAX_UARTS 6
+
+#define PIC32_SDEV_NAME "ttyS"
+#define PIC32_SDEV_MAJOR TTY_MAJOR
+#define PIC32_SDEV_MINOR 64
+
+/* pic32_sport pointer for console use */
+static struct pic32_sport *pic32_sports[PIC32_MAX_UARTS];
+
+static inline int pic32_enable_clock(struct pic32_sport *sport)
+{
+ sport->ref_clk++;
+
+ return clk_prepare_enable(sport->clk);
+}
+
+static inline void pic32_disable_clock(struct pic32_sport *sport)
+{
+ sport->ref_clk--;
+ clk_disable_unprepare(sport->clk);
+}
+
+/* serial core request to check if uart tx buffer is empty */
+static unsigned int pic32_uart_tx_empty(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+ u32 val = pic32_uart_read(sport, PIC32_UART_STA);
+
+ return (val & PIC32_UART_STA_TRMT) ? 1 : 0;
+}
+
+/* serial core request to set UART outputs */
+static void pic32_uart_set_mctrl(struct uart_port *port, unsigned int mctrl)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+
+ /* set loopback mode */
+ if (mctrl & TIOCM_LOOP)
+ pic32_uart_rset(PIC32_UART_MODE_LPBK, sport, PIC32_UART_MODE);
+ else
+ pic32_uart_rclr(PIC32_UART_MODE_LPBK, sport, PIC32_UART_MODE);
+}
+
+/* get the state of CTS input pin for this port */
+static unsigned int get_cts_state(struct pic32_sport *sport)
+{
+ /* default state must be asserted */
+ int val = 1;
+
+ /* read and invert UxCTS */
+ if (gpio_is_valid(sport->cts_gpio))
+ val = !gpio_get_value(sport->cts_gpio);
+
+ return val;
+}
+
+/* serial core request to return the state of misc UART input pins */
+static unsigned int pic32_uart_get_mctrl(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+ unsigned int mctrl = 0;
+
+ if (!sport->hw_flow_ctrl) {
+ mctrl |= TIOCM_CTS;
+ goto ret;
+ }
+
+ if (get_cts_state(sport))
+ mctrl |= TIOCM_CTS;
+
+ret:
+ /* DSR and CD are not supported in PIC32, so return 1
+ * RI is not supported in PIC32, so return 0
+ */
+ mctrl |= TIOCM_CD;
+ mctrl |= TIOCM_DSR;
+
+ return mctrl;
+}
+
+/* stop tx and start tx are not called in pairs, therefore a flag indicates
+ * the status of irq to control the irq-depth.
+ */
+static inline void pic32_uart_irqtxen(struct pic32_sport *sport, u8 en)
+{
+ if (en && !tx_irq_enabled(sport)) {
+ enable_irq(sport->irq_tx);
+ tx_irq_enabled(sport) = 1;
+ } else if (!en && tx_irq_enabled(sport)) {
+ /* use disable_irq_nosync() and not disable_irq() to avoid self
+ * imposed deadlock by not waiting for irq handler to end,
+ * since this callback is called from interrupt context.
+ */
+ disable_irq_nosync(sport->irq_tx);
+ tx_irq_enabled(sport) = 0;
+ }
+}
+
+/* serial core request to disable tx ASAP (used for flow control) */
+static void pic32_uart_stop_tx(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+
+ if (!(pic32_uart_read(sport, PIC32_UART_MODE) & PIC32_UART_MODE_ON))
+ return;
+
+ if (!(pic32_uart_read(sport, PIC32_UART_STA) & PIC32_UART_STA_UTXEN))
+ return;
+
+ /* wait for tx empty */
+ while (!(pic32_uart_read(sport, PIC32_UART_STA) & PIC32_UART_STA_TRMT))
+ udelay(1);
+
+ pic32_uart_rclr(PIC32_UART_STA_UTXEN, sport, PIC32_UART_STA);
+ pic32_uart_irqtxen(sport, 0);
+}
+
+/* serial core request to (re)enable tx */
+static void pic32_uart_start_tx(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+
+ pic32_uart_irqtxen(sport, 1);
+ pic32_uart_rset(PIC32_UART_STA_UTXEN, sport, PIC32_UART_STA);
+}
+
+/* serial core request to stop rx, called before port shutdown */
+static void pic32_uart_stop_rx(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+
+ /* disable rx interrupts */
+ disable_irq(sport->irq_rx);
+
+ /* receiver Enable bit OFF */
+ pic32_uart_rclr(PIC32_UART_STA_URXEN, sport, PIC32_UART_STA);
+}
+
+/* serial core request to start/stop emitting break char */
+static void pic32_uart_break_ctl(struct uart_port *port, int ctl)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+ unsigned long flags = 0;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ if (ctl)
+ pic32_uart_rset(PIC32_UART_STA_UTXBRK, sport, PIC32_UART_STA);
+ else
+ pic32_uart_rclr(PIC32_UART_STA_UTXBRK, sport, PIC32_UART_STA);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/* get port type in string format */
+static const char *pic32_uart_type(struct uart_port *port)
+{
+ return (port->type == PORT_PIC32) ? PIC32_DEV_NAME : NULL;
+}
+
+/* read all chars in rx fifo and send them to core */
+static void pic32_uart_do_rx(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+ struct tty_port *tty;
+ unsigned int max_count;
+
+ /* limit number of char read in interrupt, should not be
+ * higher than fifo size anyway since we're much faster than
+ * serial port
+ */
+ max_count = PIC32_UART_RX_FIFO_DEPTH;
+
+ spin_lock(&port->lock);
+
+ tty = &port->state->port;
+
+ do {
+ u32 sta_reg, c;
+ char flag;
+
+ /* get overrun/fifo empty information from status register */
+ sta_reg = pic32_uart_read(sport, PIC32_UART_STA);
+ if (unlikely(sta_reg & PIC32_UART_STA_OERR)) {
+
+ /* fifo reset is required to clear interrupt */
+ pic32_uart_rclr(PIC32_UART_STA_OERR, sport,
+ PIC32_UART_STA);
+
+ port->icount.overrun++;
+ tty_insert_flip_char(tty, 0, TTY_OVERRUN);
+ }
+
+ /* Can at least one more character can be read? */
+ if (!(sta_reg & PIC32_UART_STA_URXDA))
+ break;
+
+ /* read the character and increment the rx counter */
+ c = pic32_uart_read(sport, PIC32_UART_RX);
+
+ port->icount.rx++;
+ flag = TTY_NORMAL;
+ c &= 0xff;
+
+ if (unlikely((sta_reg & PIC32_UART_STA_PERR) ||
+ (sta_reg & PIC32_UART_STA_FERR))) {
+
+ /* do stats first */
+ if (sta_reg & PIC32_UART_STA_PERR)
+ port->icount.parity++;
+ if (sta_reg & PIC32_UART_STA_FERR)
+ port->icount.frame++;
+
+ /* update flag wrt read_status_mask */
+ sta_reg &= port->read_status_mask;
+
+ if (sta_reg & PIC32_UART_STA_FERR)
+ flag = TTY_FRAME;
+ if (sta_reg & PIC32_UART_STA_PERR)
+ flag = TTY_PARITY;
+ }
+
+ if (uart_handle_sysrq_char(port, c))
+ continue;
+
+ if ((sta_reg & port->ignore_status_mask) == 0)
+ tty_insert_flip_char(tty, c, flag);
+
+ } while (--max_count);
+
+ spin_unlock(&port->lock);
+
+ tty_flip_buffer_push(tty);
+}
+
+/* fill tx fifo with chars to send, stop when fifo is about to be full
+ * or when all chars have been sent.
+ */
+static void pic32_uart_do_tx(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+ struct circ_buf *xmit = &port->state->xmit;
+ unsigned int max_count = PIC32_UART_TX_FIFO_DEPTH;
+
+ if (port->x_char) {
+ pic32_uart_write(port->x_char, sport, PIC32_UART_TX);
+ port->icount.tx++;
+ port->x_char = 0;
+ return;
+ }
+
+ if (uart_tx_stopped(port)) {
+ pic32_uart_stop_tx(port);
+ return;
+ }
+
+ if (uart_circ_empty(xmit))
+ goto txq_empty;
+
+ /* keep stuffing chars into uart tx buffer
+ * 1) until uart fifo is full
+ * or
+ * 2) until the circ buffer is empty
+ * (all chars have been sent)
+ * or
+ * 3) until the max count is reached
+ * (prevents lingering here for too long in certain cases)
+ */
+ while (!(PIC32_UART_STA_UTXBF &
+ pic32_uart_rval(sport, PIC32_UART_STA))) {
+ unsigned int c = xmit->buf[xmit->tail];
+
+ pic32_uart_write(c, sport, PIC32_UART_TX);
+
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ port->icount.tx++;
+ --max_count;
+ if (uart_circ_empty(xmit))
+ break;
+ if (max_count == 0)
+ break;
+ }
+
+ if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+ uart_write_wakeup(port);
+
+ if (uart_circ_empty(xmit))
+ goto txq_empty;
+
+ return;
+
+txq_empty:
+ pic32_uart_irqtxen(sport, 0);
+}
+
+/* RX interrupt handler */
+static irqreturn_t pic32_uart_rx_interrupt(int irq, void *dev_id)
+{
+ struct uart_port *port = dev_id;
+
+ pic32_uart_do_rx(port);
+
+ return IRQ_HANDLED;
+}
+
+/* TX interrupt handler */
+static irqreturn_t pic32_uart_tx_interrupt(int irq, void *dev_id)
+{
+ struct uart_port *port = dev_id;
+ unsigned long flags;
+
+ spin_lock_irqsave(&port->lock, flags);
+ pic32_uart_do_tx(port);
+ spin_unlock_irqrestore(&port->lock, flags);
+
+ return IRQ_HANDLED;
+}
+
+/* FAULT interrupt handler */
+static irqreturn_t pic32_uart_fault_interrupt(int irq, void *dev_id)
+{
+ /* do nothing: pic32_uart_do_rx() handles faults. */
+ return IRQ_HANDLED;
+}
+
+/* enable rx & tx operation on uart */
+static void pic32_uart_en_and_unmask(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+
+ pic32_uart_rset(PIC32_UART_STA_UTXEN | PIC32_UART_STA_URXEN,
+ sport, PIC32_UART_STA);
+ pic32_uart_rset(PIC32_UART_MODE_ON, sport, PIC32_UART_MODE);
+}
+
+/* disable rx & tx operation on uart */
+static void pic32_uart_dsbl_and_mask(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+
+ pic32_uart_rclr(PIC32_UART_MODE_ON, sport, PIC32_UART_MODE);
+ pic32_uart_rclr(PIC32_UART_STA_UTXEN | PIC32_UART_STA_URXEN,
+ sport, PIC32_UART_STA);
+}
+
+/* serial core request to initialize uart and start rx operation */
+static int pic32_uart_startup(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+ u32 dflt_baud = ((port->uartclk / PIC32_UART_DFLT_BRATE) / 16) - 1;
+ unsigned long flags;
+ int ret = 0;
+
+ local_irq_save(flags);
+
+ ret = pic32_enable_clock(sport);
+ if (ret)
+ goto out_unlock;
+
+ /* clear status and mode registers */
+ pic32_uart_write(0, sport, PIC32_UART_MODE);
+ pic32_uart_write(0, sport, PIC32_UART_STA);
+
+ /* disable uart and mask all interrupts */
+ pic32_uart_dsbl_and_mask(port);
+
+ /* set default baud */
+ pic32_uart_write(dflt_baud, sport, PIC32_UART_BRG);
+
+ local_irq_restore(flags);
+
+ /* Each UART of a PIC32 has three interrupts therefore,
+ * we setup driver to register the 3 irqs for the device.
+ *
+ * For each irq request_irq() is called with interrupt disabled.
+ * And the irq is enabled as soon as we are ready to handle them.
+ */
+ tx_irq_enabled(sport) = 0;
+
+ sport->irq_fault_name = kasprintf(GFP_KERNEL, "%s%d-fault",
+ pic32_uart_type(port),
+ sport->idx);
+ irq_set_status_flags(sport->irq_fault, IRQ_NOAUTOEN);
+ ret = request_irq(sport->irq_fault, pic32_uart_fault_interrupt,
+ sport->irqflags_fault, sport->irq_fault_name, port);
+ if (ret) {
+ dev_err(port->dev, "%s: request irq(%d) err! ret:%d name:%s\n",
+ __func__, sport->irq_fault, ret,
+ pic32_uart_type(port));
+ goto out_done;
+ }
+
+ sport->irq_rx_name = kasprintf(GFP_KERNEL, "%s%d-rx",
+ pic32_uart_type(port),
+ sport->idx);
+ irq_set_status_flags(sport->irq_rx, IRQ_NOAUTOEN);
+ ret = request_irq(sport->irq_rx, pic32_uart_rx_interrupt,
+ sport->irqflags_rx, sport->irq_rx_name, port);
+ if (ret) {
+ dev_err(port->dev, "%s: request irq(%d) err! ret:%d name:%s\n",
+ __func__, sport->irq_rx, ret,
+ pic32_uart_type(port));
+ goto out_done;
+ }
+
+ sport->irq_tx_name = kasprintf(GFP_KERNEL, "%s%d-tx",
+ pic32_uart_type(port),
+ sport->idx);
+ irq_set_status_flags(sport->irq_tx, IRQ_NOAUTOEN);
+ ret = request_irq(sport->irq_tx, pic32_uart_tx_interrupt,
+ sport->irqflags_tx, sport->irq_tx_name, port);
+ if (ret) {
+ dev_err(port->dev, "%s: request irq(%d) err! ret:%d name:%s\n",
+ __func__, sport->irq_tx, ret,
+ pic32_uart_type(port));
+ goto out_done;
+ }
+
+ local_irq_save(flags);
+
+ /* set rx interrupt on first receive */
+ pic32_uart_rclr(PIC32_UART_STA_URXISEL1 | PIC32_UART_STA_URXISEL0,
+ sport, PIC32_UART_STA);
+
+ /* set interrupt on empty */
+ pic32_uart_rclr(PIC32_UART_STA_UTXISEL1, sport, PIC32_UART_STA);
+
+ /* enable all interrupts and eanable uart */
+ pic32_uart_en_and_unmask(port);
+
+ enable_irq(sport->irq_fault);
+ enable_irq(sport->irq_rx);
+
+out_unlock:
+ local_irq_restore(flags);
+
+out_done:
+ return ret;
+}
+
+/* serial core request to flush & disable uart */
+static void pic32_uart_shutdown(struct uart_port *port)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+ unsigned long flags;
+
+ /* disable uart */
+ spin_lock_irqsave(&port->lock, flags);
+ pic32_uart_dsbl_and_mask(port);
+ spin_unlock_irqrestore(&port->lock, flags);
+ pic32_disable_clock(sport);
+
+ /* free all 3 interrupts for this UART */
+ free_irq(sport->irq_fault, port);
+ free_irq(sport->irq_tx, port);
+ free_irq(sport->irq_rx, port);
+}
+
+/* serial core request to change current uart setting */
+static void pic32_uart_set_termios(struct uart_port *port,
+ struct ktermios *new,
+ struct ktermios *old)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+ unsigned int baud;
+ unsigned int quot;
+ unsigned long flags;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ /* disable uart and mask all interrupts while changing speed */
+ pic32_uart_dsbl_and_mask(port);
+
+ /* stop bit options */
+ if (new->c_cflag & CSTOPB)
+ pic32_uart_rset(PIC32_UART_MODE_STSEL, sport, PIC32_UART_MODE);
+ else
+ pic32_uart_rclr(PIC32_UART_MODE_STSEL, sport, PIC32_UART_MODE);
+
+ /* parity options */
+ if (new->c_cflag & PARENB) {
+ if (new->c_cflag & PARODD) {
+ pic32_uart_rset(PIC32_UART_MODE_PDSEL1, sport,
+ PIC32_UART_MODE);
+ pic32_uart_rclr(PIC32_UART_MODE_PDSEL0, sport,
+ PIC32_UART_MODE);
+ } else {
+ pic32_uart_rset(PIC32_UART_MODE_PDSEL0, sport,
+ PIC32_UART_MODE);
+ pic32_uart_rclr(PIC32_UART_MODE_PDSEL1, sport,
+ PIC32_UART_MODE);
+ }
+ } else {
+ pic32_uart_rclr(PIC32_UART_MODE_PDSEL1 | PIC32_UART_MODE_PDSEL0,
+ sport, PIC32_UART_MODE);
+ }
+ /* if hw flow ctrl, then the pins must be specified in device tree */
+ if ((new->c_cflag & CRTSCTS) && sport->hw_flow_ctrl) {
+ /* enable hardware flow control */
+ pic32_uart_rset(PIC32_UART_MODE_UEN1, sport, PIC32_UART_MODE);
+ pic32_uart_rclr(PIC32_UART_MODE_UEN0, sport, PIC32_UART_MODE);
+ pic32_uart_rclr(PIC32_UART_MODE_RTSMD, sport, PIC32_UART_MODE);
+ } else {
+ /* disable hardware flow control */
+ pic32_uart_rclr(PIC32_UART_MODE_UEN1, sport, PIC32_UART_MODE);
+ pic32_uart_rclr(PIC32_UART_MODE_UEN0, sport, PIC32_UART_MODE);
+ pic32_uart_rclr(PIC32_UART_MODE_RTSMD, sport, PIC32_UART_MODE);
+ }
+
+ /* update baud */
+ baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16);
+ quot = uart_get_divisor(port, baud) - 1;
+ pic32_uart_write(quot, sport, PIC32_UART_BRG);
+ uart_update_timeout(port, new->c_cflag, baud);
+
+ /* enable uart */
+ pic32_uart_en_and_unmask(port);
+
+ spin_unlock_irqrestore(&port->lock, flags);
+}
+
+/* serial core request to claim uart iomem */
+static int pic32_uart_request_port(struct uart_port *port)
+{
+ struct platform_device *pdev = to_platform_device(port->dev);
+ struct resource *res_mem;
+ unsigned int res_size;
+
+ res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (unlikely(!res_mem))
+ return -EINVAL;
+ res_size = resource_size(res_mem);
+
+ if (!request_mem_region(port->mapbase, res_size, "pic32_uart_mem")) {
+ dev_err(port->dev, "Memory region busy\n");
+ return -EBUSY;
+ }
+
+ port->membase = devm_ioremap_nocache(port->dev,
+ port->mapbase, res_size);
+ if (!port->membase) {
+ dev_err(port->dev, "Unable to map registers\n");
+ release_mem_region(port->mapbase, res_size);
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
+/* serial core request to release uart iomem */
+static void pic32_uart_release_port(struct uart_port *port)
+{
+ struct platform_device *pdev = to_platform_device(port->dev);
+ struct resource *res_mem;
+ unsigned int res_size;
+
+ res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (unlikely(!res_mem))
+ return;
+ res_size = resource_size(res_mem);
+
+ release_mem_region(port->mapbase, res_size);
+ devm_iounmap(port->dev, port->membase);
+}
+
+/* serial core request to do any port required auto-configuration */
+static void pic32_uart_config_port(struct uart_port *port, int flags)
+{
+ if (flags & UART_CONFIG_TYPE) {
+ if (pic32_uart_request_port(port))
+ return;
+ port->type = PORT_PIC32;
+ }
+}
+
+/* serial core request to check that port information in serinfo are suitable */
+static int pic32_uart_verify_port(struct uart_port *port,
+ struct serial_struct *serinfo)
+{
+ if (port->type != PORT_PIC32)
+ return -EINVAL;
+ if (port->irq != serinfo->irq)
+ return -EINVAL;
+ if (port->iotype != serinfo->io_type)
+ return -EINVAL;
+ if (port->mapbase != (unsigned long)serinfo->iomem_base)
+ return -EINVAL;
+
+ return 0;
+}
+
+/* serial core callbacks */
+static const struct uart_ops pic32_uart_ops = {
+ .tx_empty = pic32_uart_tx_empty,
+ .get_mctrl = pic32_uart_get_mctrl,
+ .set_mctrl = pic32_uart_set_mctrl,
+ .start_tx = pic32_uart_start_tx,
+ .stop_tx = pic32_uart_stop_tx,
+ .stop_rx = pic32_uart_stop_rx,
+ .break_ctl = pic32_uart_break_ctl,
+ .startup = pic32_uart_startup,
+ .shutdown = pic32_uart_shutdown,
+ .set_termios = pic32_uart_set_termios,
+ .type = pic32_uart_type,
+ .release_port = pic32_uart_release_port,
+ .request_port = pic32_uart_request_port,
+ .config_port = pic32_uart_config_port,
+ .verify_port = pic32_uart_verify_port,
+};
+
+#ifdef CONFIG_SERIAL_PIC32_CONSOLE
+/* output given char */
+static void pic32_console_putchar(struct uart_port *port, int ch)
+{
+ struct pic32_sport *sport = to_pic32_sport(port);
+
+ if (!(pic32_uart_read(sport, PIC32_UART_MODE) & PIC32_UART_MODE_ON))
+ return;
+
+ if (!(pic32_uart_read(sport, PIC32_UART_STA) & PIC32_UART_STA_UTXEN))
+ return;
+
+ /* wait for tx empty */
+ while (!(pic32_uart_read(sport, PIC32_UART_STA) & PIC32_UART_STA_TRMT))
+ udelay(1);
+
+ pic32_uart_write(ch & 0xff, sport, PIC32_UART_TX);
+}
+
+/* console core request to output given string */
+static void pic32_console_write(struct console *co, const char *s,
+ unsigned int count)
+{
+ struct pic32_sport *sport = pic32_sports[co->index];
+ struct uart_port *port = pic32_get_port(sport);
+
+ /* call uart helper to deal with \r\n */
+ uart_console_write(port, s, count, pic32_console_putchar);
+}
+
+/* console core request to setup given console, find matching uart
+ * port and setup it.
+ */
+static int pic32_console_setup(struct console *co, char *options)
+{
+ struct pic32_sport *sport;
+ struct uart_port *port = NULL;
+ int baud = 115200;
+ int bits = 8;
+ int parity = 'n';
+ int flow = 'n';
+ int ret = 0;
+
+ if (unlikely(co->index < 0 || co->index >= PIC32_MAX_UARTS))
+ return -ENODEV;
+
+ sport = pic32_sports[co->index];
+ if (!sport)
+ return -ENODEV;
+ port = pic32_get_port(sport);
+
+ ret = pic32_enable_clock(sport);
+ if (ret)
+ return ret;
+
+ if (options)
+ uart_parse_options(options, &baud, &parity, &bits, &flow);
+
+ return uart_set_options(port, co, baud, parity, bits, flow);
+}
+
+static struct uart_driver pic32_uart_driver;
+static struct console pic32_console = {
+ .name = PIC32_SDEV_NAME,
+ .write = pic32_console_write,
+ .device = uart_console_device,
+ .setup = pic32_console_setup,
+ .flags = CON_PRINTBUFFER,
+ .index = -1,
+ .data = &pic32_uart_driver,
+};
+#define PIC32_SCONSOLE (&pic32_console)
+
+static int __init pic32_console_init(void)
+{
+ register_console(&pic32_console);
+ return 0;
+}
+console_initcall(pic32_console_init);
+
+static inline bool is_pic32_console_port(struct uart_port *port)
+{
+ return (port->cons && port->cons->index == port->line);
+}
+
+/*
+ * Late console initialization.
+ */
+static int __init pic32_late_console_init(void)
+{
+ if (!(pic32_console.flags & CON_ENABLED))
+ register_console(&pic32_console);
+
+ return 0;
+}
+
+core_initcall(pic32_late_console_init);
+
+#else
+#define PIC32_SCONSOLE NULL
+#endif
+
+static struct uart_driver pic32_uart_driver = {
+ .owner = THIS_MODULE,
+ .driver_name = PIC32_DEV_NAME,
+ .dev_name = PIC32_SDEV_NAME,
+ .major = PIC32_SDEV_MAJOR,
+ .minor = PIC32_SDEV_MINOR,
+ .nr = PIC32_MAX_UARTS,
+ .cons = PIC32_SCONSOLE,
+};
+
+static int pic32_uart_probe(struct platform_device *pdev)
+{
+ struct device_node *np = pdev->dev.of_node;
+ struct pic32_sport *sport;
+ int uart_idx = 0;
+ struct resource *res_mem;
+ struct uart_port *port;
+ int ret = 0;
+
+ uart_idx = of_alias_get_id(np, "serial");
+ if (uart_idx < 0 || uart_idx >= PIC32_MAX_UARTS)
+ return -EINVAL;
+
+ res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res_mem)
+ return -EINVAL;
+
+ sport = devm_kzalloc(&pdev->dev, sizeof(*sport), GFP_KERNEL);
+ if (!sport)
+ return -ENOMEM;
+
+ sport->idx = uart_idx;
+ sport->irq_fault = irq_of_parse_and_map(np, 0);
+ sport->irqflags_fault = IRQF_NO_THREAD;
+ sport->irq_rx = irq_of_parse_and_map(np, 1);
+ sport->irqflags_rx = IRQF_NO_THREAD;
+ sport->irq_tx = irq_of_parse_and_map(np, 2);
+ sport->irqflags_tx = IRQF_NO_THREAD;
+ sport->clk = devm_clk_get(&pdev->dev, NULL);
+ sport->cts_gpio = -EINVAL;
+ sport->dev = &pdev->dev;
+
+ ret = pic32_enable_clock(sport);
+ if (ret) {
+ dev_err(&pdev->dev, "clk enable ?\n");
+ goto err;
+ }
+
+ /* Hardware flow control: gpios
+ * !Note: Basically, CTS is needed for reading the status.
+ */
+ sport->hw_flow_ctrl = false;
+ sport->cts_gpio = of_get_named_gpio(np, "cts-gpios", 0);
+ if (gpio_is_valid(sport->cts_gpio)) {
+ sport->hw_flow_ctrl = true;
+
+ ret = devm_gpio_request(sport->dev,
+ sport->cts_gpio, "CTS");
+ if (ret) {
+ dev_err(&pdev->dev,
+ "error requesting CTS GPIO\n");
+ goto err_disable_clk;
+ }
+
+ ret = gpio_direction_input(sport->cts_gpio);
+ if (ret) {
+ dev_err(&pdev->dev, "error setting CTS GPIO\n");
+ goto err_disable_clk;
+ }
+ }
+
+ pic32_sports[uart_idx] = sport;
+ port = &sport->port;
+ memset(port, 0, sizeof(*port));
+ port->iotype = UPIO_MEM;
+ port->mapbase = res_mem->start;
+ port->ops = &pic32_uart_ops;
+ port->flags = UPF_BOOT_AUTOCONF;
+ port->dev = &pdev->dev;
+ port->fifosize = PIC32_UART_TX_FIFO_DEPTH;
+ port->uartclk = clk_get_rate(sport->clk);
+ port->line = uart_idx;
+
+ ret = uart_add_one_port(&pic32_uart_driver, port);
+ if (ret) {
+ port->membase = NULL;
+ dev_err(port->dev, "%s: uart add port error!\n", __func__);
+ goto err_disable_clk;
+ }
+
+#ifdef CONFIG_SERIAL_PIC32_CONSOLE
+ if (is_pic32_console_port(port) &&
+ (pic32_console.flags & CON_ENABLED)) {
+ /* The peripheral clock has been enabled by console_setup,
+ * so disable it till the port is used.
+ */
+ pic32_disable_clock(sport);
+ }
+#endif
+
+ platform_set_drvdata(pdev, port);
+
+ dev_info(&pdev->dev, "%s: uart(%d) driver initialized.\n",
+ __func__, uart_idx);
+ ret = 0;
+
+err_disable_clk:
+ /* disable clock till the port is used. */
+ pic32_disable_clock(sport);
+err:
+ /* automatic unroll of sport and gpios */
+ return ret;
+}
+
+static int pic32_uart_remove(struct platform_device *pdev)
+{
+ struct uart_port *port = platform_get_drvdata(pdev);
+ struct pic32_sport *sport = to_pic32_sport(port);
+
+ uart_remove_one_port(&pic32_uart_driver, port);
+ pic32_disable_clock(sport);
+ platform_set_drvdata(pdev, NULL);
+ pic32_sports[sport->idx] = NULL;
+
+ /* automatic unroll of sport and gpios */
+ return 0;
+}
+
+static const struct of_device_id pic32_serial_dt_ids[] = {
+ { .compatible = "microchip,pic32mzda-uart" },
+ { /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, pic32_serial_dt_ids);
+
+static struct platform_driver pic32_uart_platform_driver = {
+ .probe = pic32_uart_probe,
+ .remove = pic32_uart_remove,
+ .driver = {
+ .name = PIC32_DEV_NAME,
+ .owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(pic32_serial_dt_ids),
+ },
+};
+
+static int __init pic32_uart_init(void)
+{
+ int ret;
+
+ ret = uart_register_driver(&pic32_uart_driver);
+ if (ret) {
+ pr_err("failed to register %s:%d\n",
+ pic32_uart_driver.driver_name, ret);
+ return ret;
+ }
+
+ ret = platform_driver_register(&pic32_uart_platform_driver);
+ if (ret) {
+ pr_err("fail to register pic32 uart\n");
+ uart_unregister_driver(&pic32_uart_driver);
+ }
+
+ return ret;
+}
+arch_initcall(pic32_uart_init);
+
+static void __exit pic32_uart_exit(void)
+{
+#ifdef CONFIG_SERIAL_PIC32_CONSOLE
+ unregister_console(&pic32_console);
+#endif
+ platform_driver_unregister(&pic32_uart_platform_driver);
+ uart_unregister_driver(&pic32_uart_driver);
+}
+module_exit(pic32_uart_exit);
+
+MODULE_AUTHOR("Steve Scott <steve.scott@xxxxxxxxxxxxx>");
+MODULE_DESCRIPTION("Microchip PIC32 integrated serial port driver");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/tty/serial/pic32_uart.h b/drivers/tty/serial/pic32_uart.h
new file mode 100644
index 0000000..b2f6960
--- /dev/null
+++ b/drivers/tty/serial/pic32_uart.h
@@ -0,0 +1,198 @@
+/*
+ * PIC32 Integrated Serial Driver.
+ *
+ * Copyright (C) 2015 Microchip Technology, Inc.
+ *
+ * Authors:
+ * Sorin-Andrei Pistirica <andrei.pistirica@xxxxxxxxxxxxx>
+ *
+ * Licensed under GPLv2 or later.
+ */
+#ifndef __DT_PIC32_UART_H__
+#define __DT_PIC32_UART_H__
+
+#define PIC32_UART_DFLT_BRATE (9600)
+#define PIC32_UART_TX_FIFO_DEPTH (8)
+#define PIC32_UART_RX_FIFO_DEPTH (8)
+
+struct pic32_console_opt {
+ int baud;
+ int parity;
+ int bits;
+ int flow;
+};
+/* struct pic32_sport - pic32 serial port descriptor
+ * @port: uart port descriptor
+ * @idx: port index
+ * @irq_fault: virtual fault interrupt number
+ * @irqflags_fault: flags related to fault irq
+ * @irq_fault_name: irq fault name
+ * @irq_rx: virtual rx interrupt number
+ * @irqflags_rx: flags related to rx irq
+ * @irq_rx_name: irq rx name
+ * @irq_tx: virtual tx interrupt number
+ * @irqflags_tx: : flags related to tx irq
+ * @irq_tx_name: irq tx name
+ * @cts_gpio: clear to send gpio
+ * @dev: device descriptor
+ **/
+struct pic32_sport {
+ struct uart_port port;
+ struct pic32_console_opt opt;
+ int idx;
+
+ int irq_fault;
+ int irqflags_fault;
+ const char *irq_fault_name;
+ int irq_rx;
+ int irqflags_rx;
+ const char *irq_rx_name;
+ int irq_tx;
+ int irqflags_tx;
+ const char *irq_tx_name;
+ u8 enable_tx_irq;
+
+ bool hw_flow_ctrl;
+ int cts_gpio;
+
+ int ref_clk;
+ struct clk *clk;
+
+ struct device *dev;
+};
+#define to_pic32_sport(c) container_of(c, struct pic32_sport, port)
+#define pic32_get_port(sport) (&sport->port)
+#define pic32_get_opt(sport) (&sport->opt)
+#define tx_irq_enabled(sport) (sport->enable_tx_irq)
+
+struct pic32_reg {
+ u32 val;
+ u32 clr;
+ u32 set;
+ u32 inv;
+} __packed;
+#define PIC32_REGS 4
+#define PIC32_REG_SIZE 4
+
+enum pic32_uart_regs {
+ PIC32_UART_UNKNOWN = 0,
+ PIC32_UART_MODE = 1,
+ PIC32_UART_STA = 2,
+ PIC32_UART_TX = 3,
+ PIC32_UART_RX = 4,
+ PIC32_UART_BRG = 5,
+
+ /* add above this line */
+ PIC32_UART_LAST
+};
+
+/* uart register offsets */
+static u32 pic32_uart_lookup_reg[PIC32_UART_LAST] = {
+ [PIC32_UART_MODE] = 0 * PIC32_REGS * PIC32_REG_SIZE,
+ [PIC32_UART_STA] = 1 * PIC32_REGS * PIC32_REG_SIZE,
+ [PIC32_UART_TX] = 2 * PIC32_REGS * PIC32_REG_SIZE,
+ [PIC32_UART_RX] = 3 * PIC32_REGS * PIC32_REG_SIZE,
+ [PIC32_UART_BRG] = 4 * PIC32_REGS * PIC32_REG_SIZE,
+};
+
+static inline void __iomem *pic32_uart_get_reg(struct pic32_sport *sport,
+ enum pic32_uart_regs reg)
+{
+ struct uart_port *port = pic32_get_port(sport);
+
+ return port->membase + pic32_uart_lookup_reg[reg];
+}
+
+static inline u32 pic32_uart_rval(struct pic32_sport *sport,
+ enum pic32_uart_regs reg)
+{
+ void __iomem *addr = pic32_uart_get_reg(sport, reg);
+ struct pic32_reg __iomem *reg_addr = (struct pic32_reg __iomem *)addr;
+
+ return readl(&reg_addr->val);
+}
+
+static inline void pic32_uart_rset(u32 val,
+ struct pic32_sport *sport,
+ enum pic32_uart_regs reg)
+{
+ void __iomem *addr = pic32_uart_get_reg(sport, reg);
+ struct pic32_reg __iomem *reg_addr = (struct pic32_reg __iomem *)addr;
+
+ writel(val, &reg_addr->set);
+}
+
+static inline void pic32_uart_rclr(u32 val,
+ struct pic32_sport *sport,
+ enum pic32_uart_regs reg)
+{
+ void __iomem *addr = pic32_uart_get_reg(sport, reg);
+ struct pic32_reg __iomem *reg_addr = (struct pic32_reg __iomem *)addr;
+
+ writel(val, &reg_addr->clr);
+}
+
+static inline void pic32_uart_rinv(u32 val,
+ struct pic32_sport *sport,
+ enum pic32_uart_regs reg)
+{
+ void __iomem *addr = pic32_uart_get_reg(sport, reg);
+ struct pic32_reg __iomem *reg_addr = (struct pic32_reg __iomem *)addr;
+
+ writel(val, &reg_addr->inv);
+}
+
+static inline void pic32_uart_write(u32 val,
+ struct pic32_sport *sport,
+ enum pic32_uart_regs reg)
+{
+ void __iomem *addr = pic32_uart_get_reg(sport, reg);
+
+ writel(val, addr);
+}
+
+static inline u32 pic32_uart_read(struct pic32_sport *sport,
+ enum pic32_uart_regs reg)
+{
+ void __iomem *addr = pic32_uart_get_reg(sport, reg);
+
+ return readl(addr);
+}
+
+/* pic32 uart mode register bits */
+#define PIC32_UART_MODE_ON (1 << 15)
+#define PIC32_UART_MODE_FRZ (1 << 14)
+#define PIC32_UART_MODE_SIDL (1 << 13)
+#define PIC32_UART_MODE_IREN (1 << 12)
+#define PIC32_UART_MODE_RTSMD (1 << 11)
+#define PIC32_UART_MODE_RESV1 (1 << 10)
+#define PIC32_UART_MODE_UEN1 (1 << 9)
+#define PIC32_UART_MODE_UEN0 (1 << 8)
+#define PIC32_UART_MODE_WAKE (1 << 7)
+#define PIC32_UART_MODE_LPBK (1 << 6)
+#define PIC32_UART_MODE_ABAUD (1 << 5)
+#define PIC32_UART_MODE_RXINV (1 << 4)
+#define PIC32_UART_MODE_BRGH (1 << 3)
+#define PIC32_UART_MODE_PDSEL1 (1 << 2)
+#define PIC32_UART_MODE_PDSEL0 (1 << 1)
+#define PIC32_UART_MODE_STSEL (1 << 0)
+
+/* pic32 uart status register bits */
+#define PIC32_UART_STA_UTXISEL1 (1 << 15)
+#define PIC32_UART_STA_UTXISEL0 (1 << 14)
+#define PIC32_UART_STA_UTXINV (1 << 13)
+#define PIC32_UART_STA_URXEN (1 << 12)
+#define PIC32_UART_STA_UTXBRK (1 << 11)
+#define PIC32_UART_STA_UTXEN (1 << 10)
+#define PIC32_UART_STA_UTXBF (1 << 9)
+#define PIC32_UART_STA_TRMT (1 << 8)
+#define PIC32_UART_STA_URXISEL1 (1 << 7)
+#define PIC32_UART_STA_URXISEL0 (1 << 6)
+#define PIC32_UART_STA_ADDEN (1 << 5)
+#define PIC32_UART_STA_RIDLE (1 << 4)
+#define PIC32_UART_STA_PERR (1 << 3)
+#define PIC32_UART_STA_FERR (1 << 2)
+#define PIC32_UART_STA_OERR (1 << 1)
+#define PIC32_UART_STA_URXDA (1 << 0)
+
+#endif /* __DT_PIC32_UART_H__ */
diff --git a/include/uapi/linux/serial_core.h b/include/uapi/linux/serial_core.h
index 93ba148..9df0a98 100644
--- a/include/uapi/linux/serial_core.h
+++ b/include/uapi/linux/serial_core.h
@@ -261,4 +261,7 @@
/* STM32 USART */
#define PORT_STM32 113

+/* Microchip PIC32 UART */
+#define PORT_PIC32 114
+
#endif /* _UAPILINUX_SERIAL_CORE_H */
--
1.7.9.5

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