serial: pic32_uart: Add PIC32 UART driver
This adds UART and a serial console driver for Microchip PIC32 class
devices.
[ralf@linux-mips.org: Resolved merge conflict.]
Signed-off-by: Andrei Pistirica <andrei.pistirica@microchip.com>
Signed-off-by: Joshua Henderson <joshua.henderson@microchip.com>
Reviewed-by: Alan Cox <alan@linux.intel.com>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Cc: linux-serial@vger.kernel.org
Cc: linux-api@vger.kernel.org
Patchwork: https://patchwork.linux-mips.org/patch/12101/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/drivers/tty/serial/pic32_uart.c b/drivers/tty/serial/pic32_uart.c
new file mode 100644
index 0000000..62a43bf
--- /dev/null
+++ b/drivers/tty/serial/pic32_uart.c
@@ -0,0 +1,960 @@
+/*
+ * PIC32 Integrated Serial Driver.
+ *
+ * Copyright (C) 2015 Microchip Technology, Inc.
+ *
+ * Authors:
+ * Sorin-Andrei Pistirica <andrei.pistirica@microchip.com>
+ *
+ * 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.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial_core.h>
+#include <linux/delay.h>
+
+#include <asm/mach-pic32/pic32.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 "ttyPIC"
+
+/* pic32_sport pointer for console use */
+static struct pic32_sport *pic32_sports[PIC32_MAX_UARTS];
+
+static inline void pic32_wait_deplete_txbuf(struct pic32_sport *sport)
+{
+ /* wait for tx empty, otherwise chars will be lost or corrupted */
+ while (!(pic32_uart_readl(sport, PIC32_UART_STA) & PIC32_UART_STA_TRMT))
+ udelay(1);
+}
+
+static inline int pic32_enable_clock(struct pic32_sport *sport)
+{
+ int ret = clk_prepare_enable(sport->clk);
+
+ if (ret)
+ return ret;
+
+ sport->ref_clk++;
+ return 0;
+}
+
+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_readl(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_writel(sport, PIC32_SET(PIC32_UART_MODE),
+ PIC32_UART_MODE_LPBK);
+ else
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_LPBK);
+}
+
+/* get the state of CTS input pin for this port */
+static unsigned int get_cts_state(struct pic32_sport *sport)
+{
+ /* read and invert UxCTS */
+ if (gpio_is_valid(sport->cts_gpio))
+ return !gpio_get_value(sport->cts_gpio);
+
+ return 1;
+}
+
+/* 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;
+ else if (get_cts_state(sport))
+ mctrl |= TIOCM_CTS;
+
+ /* 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_readl(sport, PIC32_UART_MODE) & PIC32_UART_MODE_ON))
+ return;
+
+ if (!(pic32_uart_readl(sport, PIC32_UART_STA) & PIC32_UART_STA_UTXEN))
+ return;
+
+ /* wait for tx empty */
+ pic32_wait_deplete_txbuf(sport);
+
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
+ PIC32_UART_STA_UTXEN);
+ 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_writel(sport, PIC32_SET(PIC32_UART_STA),
+ PIC32_UART_STA_UTXEN);
+}
+
+/* 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_writel(sport, PIC32_CLR(PIC32_UART_STA),
+ PIC32_UART_STA_URXEN);
+}
+
+/* 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;
+
+ spin_lock_irqsave(&port->lock, flags);
+
+ if (ctl)
+ pic32_uart_writel(sport, PIC32_SET(PIC32_UART_STA),
+ PIC32_UART_STA_UTXBRK);
+ else
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
+ PIC32_UART_STA_UTXBRK);
+
+ 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_readl(sport, PIC32_UART_STA);
+ if (unlikely(sta_reg & PIC32_UART_STA_OERR)) {
+
+ /* fifo reset is required to clear interrupt */
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
+ PIC32_UART_STA_OERR);
+
+ 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_readl(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_writel(sport, PIC32_UART_TX, port->x_char);
+ 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_readl(sport, PIC32_UART_STA))) {
+ unsigned int c = xmit->buf[xmit->tail];
+
+ pic32_uart_writel(sport, PIC32_UART_TX, c);
+
+ xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+ port->icount.tx++;
+ 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_writel(sport, PIC32_SET(PIC32_UART_STA),
+ PIC32_UART_STA_UTXEN | PIC32_UART_STA_URXEN);
+ pic32_uart_writel(sport, PIC32_SET(PIC32_UART_MODE),
+ PIC32_UART_MODE_ON);
+}
+
+/* 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);
+
+ /* wait for tx empty, otherwise chars will be lost or corrupted */
+ pic32_wait_deplete_txbuf(sport);
+
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
+ PIC32_UART_STA_UTXEN | PIC32_UART_STA_URXEN);
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_ON);
+}
+
+/* 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;
+
+ local_irq_save(flags);
+
+ ret = pic32_enable_clock(sport);
+ if (ret) {
+ local_irq_restore(flags);
+ goto out_done;
+ }
+
+ /* clear status and mode registers */
+ pic32_uart_writel(sport, PIC32_UART_MODE, 0);
+ pic32_uart_writel(sport, PIC32_UART_STA, 0);
+
+ /* disable uart and mask all interrupts */
+ pic32_uart_dsbl_and_mask(port);
+
+ /* set default baud */
+ pic32_uart_writel(sport, PIC32_UART_BRG, dflt_baud);
+
+ 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);
+ if (!sport->irq_fault_name) {
+ dev_err(port->dev, "%s: kasprintf err!", __func__);
+ ret = -ENOMEM;
+ goto out_done;
+ }
+ 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_f;
+ }
+
+ sport->irq_rx_name = kasprintf(GFP_KERNEL, "%s%d-rx",
+ pic32_uart_type(port),
+ sport->idx);
+ if (!sport->irq_rx_name) {
+ dev_err(port->dev, "%s: kasprintf err!", __func__);
+ kfree(sport->irq_fault_name);
+ ret = -ENOMEM;
+ goto out_f;
+ }
+ 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_r;
+ }
+
+ sport->irq_tx_name = kasprintf(GFP_KERNEL, "%s%d-tx",
+ pic32_uart_type(port),
+ sport->idx);
+ if (!sport->irq_tx_name) {
+ dev_err(port->dev, "%s: kasprintf err!", __func__);
+ ret = -ENOMEM;
+ goto out_r;
+ }
+ 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_t;
+ }
+
+ local_irq_save(flags);
+
+ /* set rx interrupt on first receive */
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
+ PIC32_UART_STA_URXISEL1 | PIC32_UART_STA_URXISEL0);
+
+ /* set interrupt on empty */
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_STA),
+ PIC32_UART_STA_UTXISEL1);
+
+ /* enable all interrupts and eanable uart */
+ pic32_uart_en_and_unmask(port);
+
+ enable_irq(sport->irq_rx);
+
+ return 0;
+
+out_t:
+ kfree(sport->irq_tx_name);
+ free_irq(sport->irq_tx, sport);
+out_r:
+ kfree(sport->irq_rx_name);
+ free_irq(sport->irq_rx, sport);
+out_f:
+ kfree(sport->irq_fault_name);
+ free_irq(sport->irq_fault, sport);
+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_writel(sport, PIC32_SET(PIC32_UART_MODE),
+ PIC32_UART_MODE_STSEL);
+ else
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_STSEL);
+
+ /* parity options */
+ if (new->c_cflag & PARENB) {
+ if (new->c_cflag & PARODD) {
+ pic32_uart_writel(sport, PIC32_SET(PIC32_UART_MODE),
+ PIC32_UART_MODE_PDSEL1);
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_PDSEL0);
+ } else {
+ pic32_uart_writel(sport, PIC32_SET(PIC32_UART_MODE),
+ PIC32_UART_MODE_PDSEL0);
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_PDSEL1);
+ }
+ } else {
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_PDSEL1 |
+ PIC32_UART_MODE_PDSEL0);
+ }
+ /* 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_writel(sport, PIC32_SET(PIC32_UART_MODE),
+ PIC32_UART_MODE_UEN1);
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_UEN0);
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_RTSMD);
+ } else {
+ /* disable hardware flow control */
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_UEN1);
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_UEN0);
+ pic32_uart_writel(sport, PIC32_CLR(PIC32_UART_MODE),
+ PIC32_UART_MODE_RTSMD);
+ }
+
+ /* Always 8-bit */
+ new->c_cflag |= CS8;
+
+ /* Mark/Space parity is not supported */
+ new->c_cflag &= ~CMSPAR;
+
+ /* update baud */
+ baud = uart_get_baud_rate(port, new, old, 0, port->uartclk / 16);
+ quot = uart_get_divisor(port, baud) - 1;
+ pic32_uart_writel(sport, PIC32_UART_BRG, quot);
+ uart_update_timeout(port, new->c_cflag, baud);
+
+ if (tty_termios_baud_rate(new))
+ tty_termios_encode_baud_rate(new, baud, 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;
+
+ res_mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (unlikely(!res_mem))
+ return -EINVAL;
+
+ if (!request_mem_region(port->mapbase, resource_size(res_mem),
+ "pic32_uart_mem"))
+ return -EBUSY;
+
+ port->membase = devm_ioremap_nocache(port->dev, port->mapbase,
+ resource_size(res_mem));
+ if (!port->membase) {
+ dev_err(port->dev, "Unable to map registers\n");
+ release_mem_region(port->mapbase, resource_size(res_mem));
+ 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);
+}
+
+/* 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_readl(sport, PIC32_UART_MODE) & PIC32_UART_MODE_ON))
+ return;
+
+ if (!(pic32_uart_readl(sport, PIC32_UART_STA) & PIC32_UART_STA_UTXEN))
+ return;
+
+ /* wait for tx empty */
+ pic32_wait_deplete_txbuf(sport);
+
+ pic32_uart_writel(sport, PIC32_UART_TX, ch & 0xff);
+}
+
+/* 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,
+ .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;
+
+ 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;
+
+ /* 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;
+ }
+
+ ret = gpio_direction_input(sport->cts_gpio);
+ if (ret) {
+ dev_err(&pdev->dev, "error setting CTS GPIO\n");
+ goto err;
+ }
+ }
+
+ 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;
+ }
+
+#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);
+
+ return 0;
+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,
+ .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("Sorin-Andrei Pistirica <andrei.pistirica@microchip.com>");
+MODULE_DESCRIPTION("Microchip PIC32 integrated serial port driver");
+MODULE_LICENSE("GPL v2");