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serial: pic32_uart: Add PIC32 UART driver

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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>
This commit is contained in:
Andrei Pistirica 2016-01-13 18:15:43 -07:00 committed by Ralf Baechle
parent 81dfdd39c7
commit 157b939470
5 changed files with 1111 additions and 0 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

21
drivers/tty/serial/Kconfig
View file

@ -900,6 +900,27 @@ 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

1
drivers/tty/serial/Makefile
View file

@ -91,6 +91,7 @@ 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_MVEBU_UART) += mvebu-uart.o
obj-$(CONFIG_SERIAL_PIC32) += pic32_uart.o
# GPIOLIB helpers for modem control lines
obj-$(CONFIG_SERIAL_MCTRL_GPIO) += serial_mctrl_gpio.o

960
drivers/tty/serial/pic32_uart.c Normal file
View file

@ -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");

126
drivers/tty/serial/pic32_uart.h Normal file
View file

@ -0,0 +1,126 @@
/*
* PIC32 Integrated Serial Driver.
*
* Copyright (C) 2015 Microchip Technology, Inc.
*
* Authors:
* Sorin-Andrei Pistirica <andrei.pistirica@microchip.com>
*
* 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)
#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_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)
static inline void pic32_uart_writel(struct pic32_sport *sport,
u32 reg, u32 val)
{
struct uart_port *port = pic32_get_port(sport);
__raw_writel(val, port->membase + reg);
}
static inline u32 pic32_uart_readl(struct pic32_sport *sport, u32 reg)
{
struct uart_port *port = pic32_get_port(sport);
return __raw_readl(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)
#endif /* __DT_PIC32_UART_H__ */

3
include/uapi/linux/serial_core.h
View file

@ -264,4 +264,7 @@
/* MVEBU UART */
#define PORT_MVEBU 114
/* Microchip PIC32 UART */
#define PORT_PIC32 114
#endif /* _UAPILINUX_SERIAL_CORE_H */