diff options
Diffstat (limited to 'drivers/tty/serial/pic32_uart.c')
| -rw-r--r-- | drivers/tty/serial/pic32_uart.c | 1004 |
1 files changed, 1004 insertions, 0 deletions
diff --git a/drivers/tty/serial/pic32_uart.c b/drivers/tty/serial/pic32_uart.c new file mode 100644 index 000000000..2beada66c --- /dev/null +++ b/drivers/tty/serial/pic32_uart.c @@ -0,0 +1,1004 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * PIC32 Integrated Serial Driver. + * + * Copyright (C) 2015 Microchip Technology, Inc. + * + * Authors: + * Sorin-Andrei Pistirica <andrei.pistirica@microchip.com> + */ + +#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> + +/* UART name and device definitions */ +#define PIC32_DEV_NAME "pic32-uart" +#define PIC32_MAX_UARTS 6 +#define PIC32_SDEV_NAME "ttyPIC" + +#define PIC32_UART_DFLT_BRATE 9600 +#define PIC32_UART_TX_FIFO_DEPTH 8 +#define PIC32_UART_RX_FIFO_DEPTH 8 + +#define PIC32_UART_MODE 0x00 +#define PIC32_UART_STA 0x10 +#define PIC32_UART_TX 0x20 +#define PIC32_UART_RX 0x30 +#define PIC32_UART_BRG 0x40 + +/* struct pic32_sport - pic32 serial port descriptor + * @port: uart port descriptor + * @idx: port index + * @irq_fault: virtual fault interrupt number + * @irq_fault_name: irq fault name + * @irq_rx: virtual rx interrupt number + * @irq_rx_name: irq rx name + * @irq_tx: virtual tx interrupt number + * @irq_tx_name: irq tx name + * @cts_gpiod: clear to send GPIO + * @dev: device descriptor + **/ +struct pic32_sport { + struct uart_port port; + int idx; + + int irq_fault; + const char *irq_fault_name; + int irq_rx; + const char *irq_rx_name; + int irq_tx; + const char *irq_tx_name; + bool enable_tx_irq; + + struct gpio_desc *cts_gpiod; + + struct clk *clk; + + struct device *dev; +}; + +static inline struct pic32_sport *to_pic32_sport(struct uart_port *port) +{ + return container_of(port, struct pic32_sport, port); +} + +static inline void pic32_uart_writel(struct pic32_sport *sport, + u32 reg, u32 val) +{ + __raw_writel(val, sport->port.membase + reg); +} + +static inline u32 pic32_uart_readl(struct pic32_sport *sport, u32 reg) +{ + return __raw_readl(sport->port.membase + reg); +} + +/* pic32 uart mode register bits */ +#define PIC32_UART_MODE_ON BIT(15) +#define PIC32_UART_MODE_FRZ BIT(14) +#define PIC32_UART_MODE_SIDL BIT(13) +#define PIC32_UART_MODE_IREN BIT(12) +#define PIC32_UART_MODE_RTSMD BIT(11) +#define PIC32_UART_MODE_RESV1 BIT(10) +#define PIC32_UART_MODE_UEN1 BIT(9) +#define PIC32_UART_MODE_UEN0 BIT(8) +#define PIC32_UART_MODE_WAKE BIT(7) +#define PIC32_UART_MODE_LPBK BIT(6) +#define PIC32_UART_MODE_ABAUD BIT(5) +#define PIC32_UART_MODE_RXINV BIT(4) +#define PIC32_UART_MODE_BRGH BIT(3) +#define PIC32_UART_MODE_PDSEL1 BIT(2) +#define PIC32_UART_MODE_PDSEL0 BIT(1) +#define PIC32_UART_MODE_STSEL BIT(0) + +/* pic32 uart status register bits */ +#define PIC32_UART_STA_UTXISEL1 BIT(15) +#define PIC32_UART_STA_UTXISEL0 BIT(14) +#define PIC32_UART_STA_UTXINV BIT(13) +#define PIC32_UART_STA_URXEN BIT(12) +#define PIC32_UART_STA_UTXBRK BIT(11) +#define PIC32_UART_STA_UTXEN BIT(10) +#define PIC32_UART_STA_UTXBF BIT(9) +#define PIC32_UART_STA_TRMT BIT(8) +#define PIC32_UART_STA_URXISEL1 BIT(7) +#define PIC32_UART_STA_URXISEL0 BIT(6) +#define PIC32_UART_STA_ADDEN BIT(5) +#define PIC32_UART_STA_RIDLE BIT(4) +#define PIC32_UART_STA_PERR BIT(3) +#define PIC32_UART_STA_FERR BIT(2) +#define PIC32_UART_STA_OERR BIT(1) +#define PIC32_UART_STA_URXDA BIT(0) + +/* 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); +} + +/* 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); +} + +/* 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; + + /* get the state of CTS input pin for this port */ + if (!sport->cts_gpiod) + mctrl |= TIOCM_CTS; + else if (gpiod_get_value(sport->cts_gpiod)) + 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 && !sport->enable_tx_irq) { + enable_irq(sport->irq_tx); + sport->enable_tx_irq = true; + } else if (!en && sport->enable_tx_irq) { + /* 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); + sport->enable_tx_irq = false; + } +} + +/* 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 = clk_prepare_enable(sport->clk); + 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. + */ + sport->enable_tx_irq = false; + + 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_disable_clk; + } + irq_set_status_flags(sport->irq_fault, IRQ_NOAUTOEN); + ret = request_irq(sport->irq_fault, pic32_uart_fault_interrupt, + IRQF_NO_THREAD, 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__); + ret = -ENOMEM; + goto out_f; + } + irq_set_status_flags(sport->irq_rx, IRQ_NOAUTOEN); + ret = request_irq(sport->irq_rx, pic32_uart_rx_interrupt, + IRQF_NO_THREAD, 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, + IRQF_NO_THREAD, 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); + + local_irq_restore(flags); + + enable_irq(sport->irq_rx); + + return 0; + +out_t: + free_irq(sport->irq_tx, port); + kfree(sport->irq_tx_name); +out_r: + free_irq(sport->irq_rx, port); + kfree(sport->irq_rx_name); +out_f: + free_irq(sport->irq_fault, port); + kfree(sport->irq_fault_name); +out_disable_clk: + clk_disable_unprepare(sport->clk); +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); + clk_disable_unprepare(sport->clk); + + /* free all 3 interrupts for this UART */ + free_irq(sport->irq_fault, port); + kfree(sport->irq_fault_name); + free_irq(sport->irq_tx, port); + kfree(sport->irq_tx_name); + free_irq(sport->irq_rx, port); + kfree(sport->irq_rx_name); +} + +/* serial core request to change current uart setting */ +static void pic32_uart_set_termios(struct uart_port *port, + struct ktermios *new, + const 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->cts_gpiod) { + /* 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(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, unsigned char 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]; + + /* call uart helper to deal with \r\n */ + uart_console_write(&sport->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; + 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; + + ret = clk_prepare_enable(sport->clk); + if (ret) + return ret; + + if (options) + uart_parse_options(options, &baud, &parity, &bits, &flow); + + return uart_set_options(&sport->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); + +/* + * 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 *dev = &pdev->dev; + struct device_node *np = 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->irq_rx = irq_of_parse_and_map(np, 1); + sport->irq_tx = irq_of_parse_and_map(np, 2); + sport->clk = devm_clk_get(&pdev->dev, NULL); + sport->dev = &pdev->dev; + + /* Hardware flow control: gpios + * !Note: Basically, CTS is needed for reading the status. + */ + sport->cts_gpiod = devm_gpiod_get_optional(dev, "cts", GPIOD_IN); + if (IS_ERR(sport->cts_gpiod)) + return dev_err_probe(dev, PTR_ERR(sport->cts_gpiod), "error requesting CTS GPIO\n"); + gpiod_set_consumer_name(sport->cts_gpiod, "CTS"); + + pic32_sports[uart_idx] = sport; + port = &sport->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 (uart_console_enabled(port)) { + /* The peripheral clock has been enabled by console_setup, + * so disable it till the port is used. + */ + clk_disable_unprepare(sport->clk); + } +#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); + clk_disable_unprepare(sport->clk); + 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), + .suppress_bind_attrs = IS_BUILTIN(CONFIG_SERIAL_PIC32), + }, +}; + +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"); |