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original_kernel/drivers/tty/serial/mvebu-uart.c

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// SPDX-License-Identifier: GPL-2.0+
/*
* ***************************************************************************
* Marvell Armada-3700 Serial Driver
* Author: Wilson Ding <dingwei@marvell.com>
* Copyright (C) 2015 Marvell International Ltd.
* ***************************************************************************
*/
#include <linux/clk.h>
#include <linux/clk-provider.h>
#include <linux/console.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/init.h>
#include <linux/io.h>
#include <linux/iopoll.h>
#include <linux/math64.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_device.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/serial.h>
#include <linux/serial_core.h>
#include <linux/slab.h>
#include <linux/tty.h>
#include <linux/tty_flip.h>
/* Register Map */
#define UART_STD_RBR 0x00
#define UART_EXT_RBR 0x18
#define UART_STD_TSH 0x04
#define UART_EXT_TSH 0x1C
#define UART_STD_CTRL1 0x08
#define UART_EXT_CTRL1 0x04
#define CTRL_SOFT_RST BIT(31)
#define CTRL_TXFIFO_RST BIT(15)
#define CTRL_RXFIFO_RST BIT(14)
#define CTRL_SND_BRK_SEQ BIT(11)
#define CTRL_BRK_DET_INT BIT(3)
#define CTRL_FRM_ERR_INT BIT(2)
#define CTRL_PAR_ERR_INT BIT(1)
#define CTRL_OVR_ERR_INT BIT(0)
#define CTRL_BRK_INT (CTRL_BRK_DET_INT | CTRL_FRM_ERR_INT | \
CTRL_PAR_ERR_INT | CTRL_OVR_ERR_INT)
#define UART_STD_CTRL2 UART_STD_CTRL1
#define UART_EXT_CTRL2 0x20
#define CTRL_STD_TX_RDY_INT BIT(5)
#define CTRL_EXT_TX_RDY_INT BIT(6)
#define CTRL_STD_RX_RDY_INT BIT(4)
#define CTRL_EXT_RX_RDY_INT BIT(5)
#define UART_STAT 0x0C
#define STAT_TX_FIFO_EMP BIT(13)
#define STAT_TX_FIFO_FUL BIT(11)
#define STAT_TX_EMP BIT(6)
#define STAT_STD_TX_RDY BIT(5)
#define STAT_EXT_TX_RDY BIT(15)
#define STAT_STD_RX_RDY BIT(4)
#define STAT_EXT_RX_RDY BIT(14)
#define STAT_BRK_DET BIT(3)
#define STAT_FRM_ERR BIT(2)
#define STAT_PAR_ERR BIT(1)
#define STAT_OVR_ERR BIT(0)
#define STAT_BRK_ERR (STAT_BRK_DET | STAT_FRM_ERR \
| STAT_PAR_ERR | STAT_OVR_ERR)
/*
* Marvell Armada 3700 Functional Specifications describes that bit 21 of UART
* Clock Control register controls UART1 and bit 20 controls UART2. But in
* reality bit 21 controls UART2 and bit 20 controls UART1. This seems to be an
* error in Marvell's documentation. Hence following CLK_DIS macros are swapped.
*/
#define UART_BRDV 0x10
/* These bits are located in UART1 address space and control UART2 */
#define UART2_CLK_DIS BIT(21)
/* These bits are located in UART1 address space and control UART1 */
#define UART1_CLK_DIS BIT(20)
/* These bits are located in UART1 address space and control both UARTs */
#define CLK_NO_XTAL BIT(19)
#define CLK_TBG_DIV1_SHIFT 15
#define CLK_TBG_DIV1_MASK 0x7
#define CLK_TBG_DIV1_MAX 6
#define CLK_TBG_DIV2_SHIFT 12
#define CLK_TBG_DIV2_MASK 0x7
#define CLK_TBG_DIV2_MAX 6
#define CLK_TBG_SEL_SHIFT 10
#define CLK_TBG_SEL_MASK 0x3
/* These bits are located in both UARTs address space */
#define BRDV_BAUD_MASK 0x3FF
#define BRDV_BAUD_MAX BRDV_BAUD_MASK
#define UART_OSAMP 0x14
#define OSAMP_DEFAULT_DIVISOR 16
#define OSAMP_DIVISORS_MASK 0x3F3F3F3F
#define OSAMP_MAX_DIVISOR 63
#define MVEBU_NR_UARTS 2
#define MVEBU_UART_TYPE "mvebu-uart"
#define DRIVER_NAME "mvebu_serial"
enum {
/* Either there is only one summed IRQ... */
UART_IRQ_SUM = 0,
/* ...or there are two separate IRQ for RX and TX */
UART_RX_IRQ = 0,
UART_TX_IRQ,
UART_IRQ_COUNT
};
/* Diverging register offsets */
struct uart_regs_layout {
unsigned int rbr;
unsigned int tsh;
unsigned int ctrl;
unsigned int intr;
};
/* Diverging flags */
struct uart_flags {
unsigned int ctrl_tx_rdy_int;
unsigned int ctrl_rx_rdy_int;
unsigned int stat_tx_rdy;
unsigned int stat_rx_rdy;
};
/* Driver data, a structure for each UART port */
struct mvebu_uart_driver_data {
bool is_ext;
struct uart_regs_layout regs;
struct uart_flags flags;
};
/* Saved registers during suspend */
struct mvebu_uart_pm_regs {
unsigned int rbr;
unsigned int tsh;
unsigned int ctrl;
unsigned int intr;
unsigned int stat;
unsigned int brdv;
unsigned int osamp;
};
/* MVEBU UART driver structure */
struct mvebu_uart {
struct uart_port *port;
struct clk *clk;
int irq[UART_IRQ_COUNT];
struct mvebu_uart_driver_data *data;
#if defined(CONFIG_PM)
struct mvebu_uart_pm_regs pm_regs;
#endif /* CONFIG_PM */
};
static struct mvebu_uart *to_mvuart(struct uart_port *port)
{
return (struct mvebu_uart *)port->private_data;
}
#define IS_EXTENDED(port) (to_mvuart(port)->data->is_ext)
#define UART_RBR(port) (to_mvuart(port)->data->regs.rbr)
#define UART_TSH(port) (to_mvuart(port)->data->regs.tsh)
#define UART_CTRL(port) (to_mvuart(port)->data->regs.ctrl)
#define UART_INTR(port) (to_mvuart(port)->data->regs.intr)
#define CTRL_TX_RDY_INT(port) (to_mvuart(port)->data->flags.ctrl_tx_rdy_int)
#define CTRL_RX_RDY_INT(port) (to_mvuart(port)->data->flags.ctrl_rx_rdy_int)
#define STAT_TX_RDY(port) (to_mvuart(port)->data->flags.stat_tx_rdy)
#define STAT_RX_RDY(port) (to_mvuart(port)->data->flags.stat_rx_rdy)
static struct uart_port mvebu_uart_ports[MVEBU_NR_UARTS];
static DEFINE_SPINLOCK(mvebu_uart_lock);
/* Core UART Driver Operations */
static unsigned int mvebu_uart_tx_empty(struct uart_port *port)
{
unsigned long flags;
unsigned int st;
spin_lock_irqsave(&port->lock, flags);
st = readl(port->membase + UART_STAT);
spin_unlock_irqrestore(&port->lock, flags);
return (st & STAT_TX_EMP) ? TIOCSER_TEMT : 0;
}
static unsigned int mvebu_uart_get_mctrl(struct uart_port *port)
{
return TIOCM_CTS | TIOCM_DSR | TIOCM_CAR;
}
static void mvebu_uart_set_mctrl(struct uart_port *port,
unsigned int mctrl)
{
/*
* Even if we do not support configuring the modem control lines, this
* function must be proided to the serial core
*/
}
static void mvebu_uart_stop_tx(struct uart_port *port)
{
unsigned int ctl = readl(port->membase + UART_INTR(port));
ctl &= ~CTRL_TX_RDY_INT(port);
writel(ctl, port->membase + UART_INTR(port));
}
static void mvebu_uart_start_tx(struct uart_port *port)
{
unsigned int ctl;
struct circ_buf *xmit = &port->state->xmit;
if (IS_EXTENDED(port) && !uart_circ_empty(xmit)) {
writel(xmit->buf[xmit->tail], port->membase + UART_TSH(port));
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
}
ctl = readl(port->membase + UART_INTR(port));
ctl |= CTRL_TX_RDY_INT(port);
writel(ctl, port->membase + UART_INTR(port));
}
static void mvebu_uart_stop_rx(struct uart_port *port)
{
unsigned int ctl;
ctl = readl(port->membase + UART_CTRL(port));
ctl &= ~CTRL_BRK_INT;
writel(ctl, port->membase + UART_CTRL(port));
ctl = readl(port->membase + UART_INTR(port));
ctl &= ~CTRL_RX_RDY_INT(port);
writel(ctl, port->membase + UART_INTR(port));
}
static void mvebu_uart_break_ctl(struct uart_port *port, int brk)
{
unsigned int ctl;
unsigned long flags;
spin_lock_irqsave(&port->lock, flags);
ctl = readl(port->membase + UART_CTRL(port));
if (brk == -1)
ctl |= CTRL_SND_BRK_SEQ;
else
ctl &= ~CTRL_SND_BRK_SEQ;
writel(ctl, port->membase + UART_CTRL(port));
spin_unlock_irqrestore(&port->lock, flags);
}
static void mvebu_uart_rx_chars(struct uart_port *port, unsigned int status)
{
struct tty_port *tport = &port->state->port;
unsigned char ch = 0;
char flag = 0;
do {
if (status & STAT_RX_RDY(port)) {
ch = readl(port->membase + UART_RBR(port));
ch &= 0xff;
flag = TTY_NORMAL;
port->icount.rx++;
if (status & STAT_PAR_ERR)
port->icount.parity++;
}
if (status & STAT_BRK_DET) {
port->icount.brk++;
status &= ~(STAT_FRM_ERR | STAT_PAR_ERR);
if (uart_handle_break(port))
goto ignore_char;
}
if (status & STAT_OVR_ERR)
port->icount.overrun++;
if (status & STAT_FRM_ERR)
port->icount.frame++;
if (uart_handle_sysrq_char(port, ch))
goto ignore_char;
if (status & port->ignore_status_mask & STAT_PAR_ERR)
status &= ~STAT_RX_RDY(port);
status &= port->read_status_mask;
if (status & STAT_PAR_ERR)
flag = TTY_PARITY;
status &= ~port->ignore_status_mask;
if (status & STAT_RX_RDY(port))
tty_insert_flip_char(tport, ch, flag);
if (status & STAT_BRK_DET)
tty_insert_flip_char(tport, 0, TTY_BREAK);
if (status & STAT_FRM_ERR)
tty_insert_flip_char(tport, 0, TTY_FRAME);
if (status & STAT_OVR_ERR)
tty_insert_flip_char(tport, 0, TTY_OVERRUN);
ignore_char:
status = readl(port->membase + UART_STAT);
} while (status & (STAT_RX_RDY(port) | STAT_BRK_DET));
tty_flip_buffer_push(tport);
}
static void mvebu_uart_tx_chars(struct uart_port *port, unsigned int status)
{
struct circ_buf *xmit = &port->state->xmit;
unsigned int count;
unsigned int st;
if (port->x_char) {
writel(port->x_char, port->membase + UART_TSH(port));
port->icount.tx++;
port->x_char = 0;
return;
}
if (uart_circ_empty(xmit) || uart_tx_stopped(port)) {
mvebu_uart_stop_tx(port);
return;
}
for (count = 0; count < port->fifosize; count++) {
writel(xmit->buf[xmit->tail], port->membase + UART_TSH(port));
xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
port->icount.tx++;
if (uart_circ_empty(xmit))
break;
st = readl(port->membase + UART_STAT);
if (st & STAT_TX_FIFO_FUL)
break;
}
if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
uart_write_wakeup(port);
if (uart_circ_empty(xmit))
mvebu_uart_stop_tx(port);
}
static irqreturn_t mvebu_uart_isr(int irq, void *dev_id)
{
struct uart_port *port = (struct uart_port *)dev_id;
unsigned int st = readl(port->membase + UART_STAT);
if (st & (STAT_RX_RDY(port) | STAT_OVR_ERR | STAT_FRM_ERR |
STAT_BRK_DET))
mvebu_uart_rx_chars(port, st);
if (st & STAT_TX_RDY(port))
mvebu_uart_tx_chars(port, st);
return IRQ_HANDLED;
}
static irqreturn_t mvebu_uart_rx_isr(int irq, void *dev_id)
{
struct uart_port *port = (struct uart_port *)dev_id;
unsigned int st = readl(port->membase + UART_STAT);
if (st & (STAT_RX_RDY(port) | STAT_OVR_ERR | STAT_FRM_ERR |
STAT_BRK_DET))
mvebu_uart_rx_chars(port, st);
return IRQ_HANDLED;
}
static irqreturn_t mvebu_uart_tx_isr(int irq, void *dev_id)
{
struct uart_port *port = (struct uart_port *)dev_id;
unsigned int st = readl(port->membase + UART_STAT);
if (st & STAT_TX_RDY(port))
mvebu_uart_tx_chars(port, st);
return IRQ_HANDLED;
}
static int mvebu_uart_startup(struct uart_port *port)
{
struct mvebu_uart *mvuart = to_mvuart(port);
unsigned int ctl;
int ret;
writel(CTRL_TXFIFO_RST | CTRL_RXFIFO_RST,
port->membase + UART_CTRL(port));
udelay(1);
/* Clear the error bits of state register before IRQ request */
ret = readl(port->membase + UART_STAT);
ret |= STAT_BRK_ERR;
writel(ret, port->membase + UART_STAT);
writel(CTRL_BRK_INT, port->membase + UART_CTRL(port));
ctl = readl(port->membase + UART_INTR(port));
ctl |= CTRL_RX_RDY_INT(port);
writel(ctl, port->membase + UART_INTR(port));
if (!mvuart->irq[UART_TX_IRQ]) {
/* Old bindings with just one interrupt (UART0 only) */
ret = devm_request_irq(port->dev, mvuart->irq[UART_IRQ_SUM],
mvebu_uart_isr, port->irqflags,
dev_name(port->dev), port);
if (ret) {
dev_err(port->dev, "unable to request IRQ %d\n",
mvuart->irq[UART_IRQ_SUM]);
return ret;
}
} else {
/* New bindings with an IRQ for RX and TX (both UART) */
ret = devm_request_irq(port->dev, mvuart->irq[UART_RX_IRQ],
mvebu_uart_rx_isr, port->irqflags,
dev_name(port->dev), port);
if (ret) {
dev_err(port->dev, "unable to request IRQ %d\n",
mvuart->irq[UART_RX_IRQ]);
return ret;
}
ret = devm_request_irq(port->dev, mvuart->irq[UART_TX_IRQ],
mvebu_uart_tx_isr, port->irqflags,
dev_name(port->dev),
port);
if (ret) {
dev_err(port->dev, "unable to request IRQ %d\n",
mvuart->irq[UART_TX_IRQ]);
devm_free_irq(port->dev, mvuart->irq[UART_RX_IRQ],
port);
return ret;
}
}
return 0;
}
static void mvebu_uart_shutdown(struct uart_port *port)
{
struct mvebu_uart *mvuart = to_mvuart(port);
writel(0, port->membase + UART_INTR(port));
if (!mvuart->irq[UART_TX_IRQ]) {
devm_free_irq(port->dev, mvuart->irq[UART_IRQ_SUM], port);
} else {
devm_free_irq(port->dev, mvuart->irq[UART_RX_IRQ], port);
devm_free_irq(port->dev, mvuart->irq[UART_TX_IRQ], port);
}
}
static int mvebu_uart_baud_rate_set(struct uart_port *port, unsigned int baud)
{
unsigned int d_divisor, m_divisor;
unsigned long flags;
u32 brdv, osamp;
if (!port->uartclk)
return -EOPNOTSUPP;
/*
* The baudrate is derived from the UART clock thanks to divisors:
* > d1 * d2 ("TBG divisors"): can divide only TBG clock from 1 to 6
* > D ("baud generator"): can divide the clock from 1 to 1023
* > M ("fractional divisor"): allows a better accuracy (from 1 to 63)
*
* Exact formulas for calculating baudrate:
*
* with default x16 scheme:
* baudrate = xtal / (d * 16)
* baudrate = tbg / (d1 * d2 * d * 16)
*
* with fractional divisor:
* baudrate = 10 * xtal / (d * (3 * (m1 + m2) + 2 * (m3 + m4)))
* baudrate = 10 * tbg / (d1*d2 * d * (3 * (m1 + m2) + 2 * (m3 + m4)))
*
* Oversampling value:
* osamp = (m1 << 0) | (m2 << 8) | (m3 << 16) | (m4 << 24);
*
* Where m1 controls number of clock cycles per bit for bits 1,2,3;
* m2 for bits 4,5,6; m3 for bits 7,8 and m4 for bits 9,10.
*
* To simplify baudrate setup set all the M prescalers to the same
* value. For baudrates 9600 Bd and higher, it is enough to use the
* default (x16) divisor or fractional divisor with M = 63, so there
* is no need to use real fractional support (where the M prescalers
* are not equal).
*
* When all the M prescalers are zeroed then default (x16) divisor is
* used. Default x16 scheme is more stable than M (fractional divisor),
* so use M only when D divisor is not enough to derive baudrate.
*
* Member port->uartclk is either xtal clock rate or TBG clock rate
* divided by (d1 * d2). So d1 and d2 are already set by the UART clock
* driver (and UART driver itself cannot change them). Moreover they are
* shared between both UARTs.
*/
m_divisor = OSAMP_DEFAULT_DIVISOR;
d_divisor = DIV_ROUND_CLOSEST(port->uartclk, baud * m_divisor);
if (d_divisor > BRDV_BAUD_MAX) {
/*
* Experiments show that small M divisors are unstable.
* Use maximal possible M = 63 and calculate D divisor.
*/
m_divisor = OSAMP_MAX_DIVISOR;
d_divisor = DIV_ROUND_CLOSEST(port->uartclk, baud * m_divisor);
}
if (d_divisor < 1)
d_divisor = 1;
else if (d_divisor > BRDV_BAUD_MAX)
d_divisor = BRDV_BAUD_MAX;
spin_lock_irqsave(&mvebu_uart_lock, flags);
brdv = readl(port->membase + UART_BRDV);
brdv &= ~BRDV_BAUD_MASK;
brdv |= d_divisor;
writel(brdv, port->membase + UART_BRDV);
spin_unlock_irqrestore(&mvebu_uart_lock, flags);
osamp = readl(port->membase + UART_OSAMP);
osamp &= ~OSAMP_DIVISORS_MASK;
if (m_divisor != OSAMP_DEFAULT_DIVISOR)
osamp |= (m_divisor << 0) | (m_divisor << 8) |
(m_divisor << 16) | (m_divisor << 24);
writel(osamp, port->membase + UART_OSAMP);
return 0;
}
static void mvebu_uart_set_termios(struct uart_port *port,
struct ktermios *termios,
struct ktermios *old)
{
unsigned long flags;
unsigned int baud, min_baud, max_baud;
spin_lock_irqsave(&port->lock, flags);
port->read_status_mask = STAT_RX_RDY(port) | STAT_OVR_ERR |
STAT_TX_RDY(port) | STAT_TX_FIFO_FUL;
if (termios->c_iflag & INPCK)
port->read_status_mask |= STAT_FRM_ERR | STAT_PAR_ERR;
port->ignore_status_mask = 0;
if (termios->c_iflag & IGNPAR)
port->ignore_status_mask |=
STAT_FRM_ERR | STAT_PAR_ERR | STAT_OVR_ERR;
if ((termios->c_cflag & CREAD) == 0)
port->ignore_status_mask |= STAT_RX_RDY(port) | STAT_BRK_ERR;
/*
* Maximal divisor is 1023 and maximal fractional divisor is 63. And
* experiments show that baudrates above 1/80 of parent clock rate are
* not stable. So disallow baudrates above 1/80 of the parent clock
* rate. If port->uartclk is not available, then
* mvebu_uart_baud_rate_set() fails, so values min_baud and max_baud
* in this case do not matter.
*/
min_baud = DIV_ROUND_UP(port->uartclk, BRDV_BAUD_MAX *
OSAMP_MAX_DIVISOR);
max_baud = port->uartclk / 80;
baud = uart_get_baud_rate(port, termios, old, min_baud, max_baud);
if (mvebu_uart_baud_rate_set(port, baud)) {
/* No clock available, baudrate cannot be changed */
if (old)
baud = uart_get_baud_rate(port, old, NULL,
min_baud, max_baud);
} else {
tty_termios_encode_baud_rate(termios, baud, baud);
uart_update_timeout(port, termios->c_cflag, baud);
}
/* Only the following flag changes are supported */
if (old) {
termios->c_iflag &= INPCK | IGNPAR;
termios->c_iflag |= old->c_iflag & ~(INPCK | IGNPAR);
termios->c_cflag &= CREAD | CBAUD;
termios->c_cflag |= old->c_cflag & ~(CREAD | CBAUD);
termios->c_cflag |= CS8;
}
spin_unlock_irqrestore(&port->lock, flags);
}
static const char *mvebu_uart_type(struct uart_port *port)
{
return MVEBU_UART_TYPE;
}
static void mvebu_uart_release_port(struct uart_port *port)
{
/* Nothing to do here */
}
static int mvebu_uart_request_port(struct uart_port *port)
{
return 0;
}
#ifdef CONFIG_CONSOLE_POLL
static int mvebu_uart_get_poll_char(struct uart_port *port)
{
unsigned int st = readl(port->membase + UART_STAT);
if (!(st & STAT_RX_RDY(port)))
return NO_POLL_CHAR;
return readl(port->membase + UART_RBR(port));
}
static void mvebu_uart_put_poll_char(struct uart_port *port, unsigned char c)
{
unsigned int st;
for (;;) {
st = readl(port->membase + UART_STAT);
if (!(st & STAT_TX_FIFO_FUL))
break;
udelay(1);
}
writel(c, port->membase + UART_TSH(port));
}
#endif
static const struct uart_ops mvebu_uart_ops = {
.tx_empty = mvebu_uart_tx_empty,
.set_mctrl = mvebu_uart_set_mctrl,
.get_mctrl = mvebu_uart_get_mctrl,
.stop_tx = mvebu_uart_stop_tx,
.start_tx = mvebu_uart_start_tx,
.stop_rx = mvebu_uart_stop_rx,
.break_ctl = mvebu_uart_break_ctl,
.startup = mvebu_uart_startup,
.shutdown = mvebu_uart_shutdown,
.set_termios = mvebu_uart_set_termios,
.type = mvebu_uart_type,
.release_port = mvebu_uart_release_port,
.request_port = mvebu_uart_request_port,
#ifdef CONFIG_CONSOLE_POLL
.poll_get_char = mvebu_uart_get_poll_char,
.poll_put_char = mvebu_uart_put_poll_char,
#endif
};
/* Console Driver Operations */
#ifdef CONFIG_SERIAL_MVEBU_CONSOLE
/* Early Console */
static void mvebu_uart_putc(struct uart_port *port, unsigned char c)
{
unsigned int st;
for (;;) {
st = readl(port->membase + UART_STAT);
if (!(st & STAT_TX_FIFO_FUL))
break;
}
/* At early stage, DT is not parsed yet, only use UART0 */
writel(c, port->membase + UART_STD_TSH);
for (;;) {
st = readl(port->membase + UART_STAT);
if (st & STAT_TX_FIFO_EMP)
break;
}
}
static void mvebu_uart_putc_early_write(struct console *con,
const char *s,
unsigned int n)
{
struct earlycon_device *dev = con->data;
uart_console_write(&dev->port, s, n, mvebu_uart_putc);
}
static int __init
mvebu_uart_early_console_setup(struct earlycon_device *device,
const char *opt)
{
if (!device->port.membase)
return -ENODEV;
device->con->write = mvebu_uart_putc_early_write;
return 0;
}
EARLYCON_DECLARE(ar3700_uart, mvebu_uart_early_console_setup);
OF_EARLYCON_DECLARE(ar3700_uart, "marvell,armada-3700-uart",
mvebu_uart_early_console_setup);
static void wait_for_xmitr(struct uart_port *port)
{
u32 val;
readl_poll_timeout_atomic(port->membase + UART_STAT, val,
(val & STAT_TX_RDY(port)), 1, 10000);
}
static void wait_for_xmite(struct uart_port *port)
{
u32 val;
readl_poll_timeout_atomic(port->membase + UART_STAT, val,
(val & STAT_TX_EMP), 1, 10000);
}
static void mvebu_uart_console_putchar(struct uart_port *port, unsigned char ch)
{
wait_for_xmitr(port);
writel(ch, port->membase + UART_TSH(port));
}
static void mvebu_uart_console_write(struct console *co, const char *s,
unsigned int count)
{
struct uart_port *port = &mvebu_uart_ports[co->index];
unsigned long flags;
unsigned int ier, intr, ctl;
int locked = 1;
if (oops_in_progress)
locked = spin_trylock_irqsave(&port->lock, flags);
else
spin_lock_irqsave(&port->lock, flags);
ier = readl(port->membase + UART_CTRL(port)) & CTRL_BRK_INT;
intr = readl(port->membase + UART_INTR(port)) &
(CTRL_RX_RDY_INT(port) | CTRL_TX_RDY_INT(port));
writel(0, port->membase + UART_CTRL(port));
writel(0, port->membase + UART_INTR(port));
uart_console_write(port, s, count, mvebu_uart_console_putchar);
wait_for_xmite(port);
if (ier)
writel(ier, port->membase + UART_CTRL(port));
if (intr) {
ctl = intr | readl(port->membase + UART_INTR(port));
writel(ctl, port->membase + UART_INTR(port));
}
if (locked)
spin_unlock_irqrestore(&port->lock, flags);
}
static int mvebu_uart_console_setup(struct console *co, char *options)
{
struct uart_port *port;
int baud = 9600;
int bits = 8;
int parity = 'n';
int flow = 'n';
if (co->index < 0 || co->index >= MVEBU_NR_UARTS)
return -EINVAL;
port = &mvebu_uart_ports[co->index];
if (!port->mapbase || !port->membase) {
pr_debug("console on ttyMV%i not present\n", co->index);
return -ENODEV;
}
if (options)
uart_parse_options(options, &baud, &parity, &bits, &flow);
return uart_set_options(port, co, baud, parity, bits, flow);
}
static struct uart_driver mvebu_uart_driver;
static struct console mvebu_uart_console = {
.name = "ttyMV",
.write = mvebu_uart_console_write,
.device = uart_console_device,
.setup = mvebu_uart_console_setup,
.flags = CON_PRINTBUFFER,
.index = -1,
.data = &mvebu_uart_driver,
};
static int __init mvebu_uart_console_init(void)
{
register_console(&mvebu_uart_console);
return 0;
}
console_initcall(mvebu_uart_console_init);
#endif /* CONFIG_SERIAL_MVEBU_CONSOLE */
static struct uart_driver mvebu_uart_driver = {
.owner = THIS_MODULE,
.driver_name = DRIVER_NAME,
.dev_name = "ttyMV",
.nr = MVEBU_NR_UARTS,
#ifdef CONFIG_SERIAL_MVEBU_CONSOLE
.cons = &mvebu_uart_console,
#endif
};
#if defined(CONFIG_PM)
static int mvebu_uart_suspend(struct device *dev)
{
struct mvebu_uart *mvuart = dev_get_drvdata(dev);
struct uart_port *port = mvuart->port;
unsigned long flags;
uart_suspend_port(&mvebu_uart_driver, port);
mvuart->pm_regs.rbr = readl(port->membase + UART_RBR(port));
mvuart->pm_regs.tsh = readl(port->membase + UART_TSH(port));
mvuart->pm_regs.ctrl = readl(port->membase + UART_CTRL(port));
mvuart->pm_regs.intr = readl(port->membase + UART_INTR(port));
mvuart->pm_regs.stat = readl(port->membase + UART_STAT);
spin_lock_irqsave(&mvebu_uart_lock, flags);
mvuart->pm_regs.brdv = readl(port->membase + UART_BRDV);
spin_unlock_irqrestore(&mvebu_uart_lock, flags);
mvuart->pm_regs.osamp = readl(port->membase + UART_OSAMP);
device_set_wakeup_enable(dev, true);
return 0;
}
static int mvebu_uart_resume(struct device *dev)
{
struct mvebu_uart *mvuart = dev_get_drvdata(dev);
struct uart_port *port = mvuart->port;
unsigned long flags;
writel(mvuart->pm_regs.rbr, port->membase + UART_RBR(port));
writel(mvuart->pm_regs.tsh, port->membase + UART_TSH(port));
writel(mvuart->pm_regs.ctrl, port->membase + UART_CTRL(port));
writel(mvuart->pm_regs.intr, port->membase + UART_INTR(port));
writel(mvuart->pm_regs.stat, port->membase + UART_STAT);
spin_lock_irqsave(&mvebu_uart_lock, flags);
writel(mvuart->pm_regs.brdv, port->membase + UART_BRDV);
spin_unlock_irqrestore(&mvebu_uart_lock, flags);
writel(mvuart->pm_regs.osamp, port->membase + UART_OSAMP);
uart_resume_port(&mvebu_uart_driver, port);
return 0;
}
static const struct dev_pm_ops mvebu_uart_pm_ops = {
.suspend = mvebu_uart_suspend,
.resume = mvebu_uart_resume,
};
#endif /* CONFIG_PM */
static const struct of_device_id mvebu_uart_of_match[];
/* Counter to keep track of each UART port id when not using CONFIG_OF */
static int uart_num_counter;
static int mvebu_uart_probe(struct platform_device *pdev)
{
struct resource *reg = platform_get_resource(pdev, IORESOURCE_MEM, 0);
const struct of_device_id *match = of_match_device(mvebu_uart_of_match,
&pdev->dev);
struct uart_port *port;
struct mvebu_uart *mvuart;
int id, irq;
if (!reg) {
dev_err(&pdev->dev, "no registers defined\n");
return -EINVAL;
}
/* Assume that all UART ports have a DT alias or none has */
id = of_alias_get_id(pdev->dev.of_node, "serial");
if (!pdev->dev.of_node || id < 0)
pdev->id = uart_num_counter++;
else
pdev->id = id;
if (pdev->id >= MVEBU_NR_UARTS) {
dev_err(&pdev->dev, "cannot have more than %d UART ports\n",
MVEBU_NR_UARTS);
return -EINVAL;
}
port = &mvebu_uart_ports[pdev->id];
spin_lock_init(&port->lock);
port->dev = &pdev->dev;
port->type = PORT_MVEBU;
port->ops = &mvebu_uart_ops;
port->regshift = 0;
port->fifosize = 32;
port->iotype = UPIO_MEM32;
port->flags = UPF_FIXED_PORT;
port->line = pdev->id;
/*
* IRQ number is not stored in this structure because we may have two of
* them per port (RX and TX). Instead, use the driver UART structure
* array so called ->irq[].
*/
port->irq = 0;
port->irqflags = 0;
port->mapbase = reg->start;
port->membase = devm_ioremap_resource(&pdev->dev, reg);
if (IS_ERR(port->membase))
return PTR_ERR(port->membase);
mvuart = devm_kzalloc(&pdev->dev, sizeof(struct mvebu_uart),
GFP_KERNEL);
if (!mvuart)
return -ENOMEM;
/* Get controller data depending on the compatible string */
mvuart->data = (struct mvebu_uart_driver_data *)match->data;
mvuart->port = port;
port->private_data = mvuart;
platform_set_drvdata(pdev, mvuart);
/* Get fixed clock frequency */
mvuart->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(mvuart->clk)) {
if (PTR_ERR(mvuart->clk) == -EPROBE_DEFER)
return PTR_ERR(mvuart->clk);
if (IS_EXTENDED(port)) {
dev_err(&pdev->dev, "unable to get UART clock\n");
return PTR_ERR(mvuart->clk);
}
} else {
if (!clk_prepare_enable(mvuart->clk))
port->uartclk = clk_get_rate(mvuart->clk);
}
/* Manage interrupts */
if (platform_irq_count(pdev) == 1) {
/* Old bindings: no name on the single unamed UART0 IRQ */
irq = platform_get_irq(pdev, 0);
if (irq < 0)
return irq;
mvuart->irq[UART_IRQ_SUM] = irq;
} else {
/*
* New bindings: named interrupts (RX, TX) for both UARTS,
* only make use of uart-rx and uart-tx interrupts, do not use
* uart-sum of UART0 port.
*/
irq = platform_get_irq_byname(pdev, "uart-rx");
if (irq < 0)
return irq;
mvuart->irq[UART_RX_IRQ] = irq;
irq = platform_get_irq_byname(pdev, "uart-tx");
if (irq < 0)
return irq;
mvuart->irq[UART_TX_IRQ] = irq;
}
/* UART Soft Reset*/
writel(CTRL_SOFT_RST, port->membase + UART_CTRL(port));
udelay(1);
writel(0, port->membase + UART_CTRL(port));
return uart_add_one_port(&mvebu_uart_driver, port);
}
static struct mvebu_uart_driver_data uart_std_driver_data = {
.is_ext = false,
.regs.rbr = UART_STD_RBR,
.regs.tsh = UART_STD_TSH,
.regs.ctrl = UART_STD_CTRL1,
.regs.intr = UART_STD_CTRL2,
.flags.ctrl_tx_rdy_int = CTRL_STD_TX_RDY_INT,
.flags.ctrl_rx_rdy_int = CTRL_STD_RX_RDY_INT,
.flags.stat_tx_rdy = STAT_STD_TX_RDY,
.flags.stat_rx_rdy = STAT_STD_RX_RDY,
};
static struct mvebu_uart_driver_data uart_ext_driver_data = {
.is_ext = true,
.regs.rbr = UART_EXT_RBR,
.regs.tsh = UART_EXT_TSH,
.regs.ctrl = UART_EXT_CTRL1,
.regs.intr = UART_EXT_CTRL2,
.flags.ctrl_tx_rdy_int = CTRL_EXT_TX_RDY_INT,
.flags.ctrl_rx_rdy_int = CTRL_EXT_RX_RDY_INT,
.flags.stat_tx_rdy = STAT_EXT_TX_RDY,
.flags.stat_rx_rdy = STAT_EXT_RX_RDY,
};
/* Match table for of_platform binding */
static const struct of_device_id mvebu_uart_of_match[] = {
{
.compatible = "marvell,armada-3700-uart",
.data = (void *)&uart_std_driver_data,
},
{
.compatible = "marvell,armada-3700-uart-ext",
.data = (void *)&uart_ext_driver_data,
},
{}
};
static struct platform_driver mvebu_uart_platform_driver = {
.probe = mvebu_uart_probe,
.driver = {
.name = "mvebu-uart",
.of_match_table = of_match_ptr(mvebu_uart_of_match),
.suppress_bind_attrs = true,
#if defined(CONFIG_PM)
.pm = &mvebu_uart_pm_ops,
#endif /* CONFIG_PM */
},
};
/* This code is based on clk-fixed-factor.c driver and modified. */
struct mvebu_uart_clock {
struct clk_hw clk_hw;
int clock_idx;
u32 pm_context_reg1;
u32 pm_context_reg2;
};
struct mvebu_uart_clock_base {
struct mvebu_uart_clock clocks[2];
unsigned int parent_rates[5];
int parent_idx;
unsigned int div;
void __iomem *reg1;
void __iomem *reg2;
bool configured;
};
#define PARENT_CLOCK_XTAL 4
#define to_uart_clock(hw) container_of(hw, struct mvebu_uart_clock, clk_hw)
#define to_uart_clock_base(uart_clock) container_of(uart_clock, \
struct mvebu_uart_clock_base, clocks[uart_clock->clock_idx])
static int mvebu_uart_clock_prepare(struct clk_hw *hw)
{
struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
struct mvebu_uart_clock_base *uart_clock_base =
to_uart_clock_base(uart_clock);
unsigned int prev_clock_idx, prev_clock_rate, prev_d1d2;
unsigned int parent_clock_idx, parent_clock_rate;
unsigned long flags;
unsigned int d1, d2;
u64 divisor;
u32 val;
/*
* This function just reconfigures UART Clock Control register (located
* in UART1 address space which controls both UART1 and UART2) to
* selected UART base clock and recalculates current UART1/UART2
* divisors in their address spaces, so that final baudrate will not be
* changed by switching UART parent clock. This is required for
* otherwise kernel's boot log stops working - we need to ensure that
* UART baudrate does not change during this setup. It is a one time
* operation, it will execute only once and set `configured` to true,
* and be skipped on subsequent calls. Because this UART Clock Control
* register (UART_BRDV) is shared between UART1 baudrate function,
* UART1 clock selector and UART2 clock selector, every access to
* UART_BRDV (reg1) needs to be protected by a lock.
*/
spin_lock_irqsave(&mvebu_uart_lock, flags);
if (uart_clock_base->configured) {
spin_unlock_irqrestore(&mvebu_uart_lock, flags);
return 0;
}
parent_clock_idx = uart_clock_base->parent_idx;
parent_clock_rate = uart_clock_base->parent_rates[parent_clock_idx];
val = readl(uart_clock_base->reg1);
if (uart_clock_base->div > CLK_TBG_DIV1_MAX) {
d1 = CLK_TBG_DIV1_MAX;
d2 = uart_clock_base->div / CLK_TBG_DIV1_MAX;
} else {
d1 = uart_clock_base->div;
d2 = 1;
}
if (val & CLK_NO_XTAL) {
prev_clock_idx = (val >> CLK_TBG_SEL_SHIFT) & CLK_TBG_SEL_MASK;
prev_d1d2 = ((val >> CLK_TBG_DIV1_SHIFT) & CLK_TBG_DIV1_MASK) *
((val >> CLK_TBG_DIV2_SHIFT) & CLK_TBG_DIV2_MASK);
} else {
prev_clock_idx = PARENT_CLOCK_XTAL;
prev_d1d2 = 1;
}
/* Note that uart_clock_base->parent_rates[i] may not be available */
prev_clock_rate = uart_clock_base->parent_rates[prev_clock_idx];
/* Recalculate UART1 divisor so UART1 baudrate does not change */
if (prev_clock_rate) {
divisor = DIV_U64_ROUND_CLOSEST((u64)(val & BRDV_BAUD_MASK) *
parent_clock_rate * prev_d1d2,
prev_clock_rate * d1 * d2);
if (divisor < 1)
divisor = 1;
else if (divisor > BRDV_BAUD_MAX)
divisor = BRDV_BAUD_MAX;
val = (val & ~BRDV_BAUD_MASK) | divisor;
}
if (parent_clock_idx != PARENT_CLOCK_XTAL) {
/* Do not use XTAL, select TBG clock and TBG d1 * d2 divisors */
val |= CLK_NO_XTAL;
val &= ~(CLK_TBG_DIV1_MASK << CLK_TBG_DIV1_SHIFT);
val |= d1 << CLK_TBG_DIV1_SHIFT;
val &= ~(CLK_TBG_DIV2_MASK << CLK_TBG_DIV2_SHIFT);
val |= d2 << CLK_TBG_DIV2_SHIFT;
val &= ~(CLK_TBG_SEL_MASK << CLK_TBG_SEL_SHIFT);
val |= parent_clock_idx << CLK_TBG_SEL_SHIFT;
} else {
/* Use XTAL, TBG bits are then ignored */
val &= ~CLK_NO_XTAL;
}
writel(val, uart_clock_base->reg1);
/* Recalculate UART2 divisor so UART2 baudrate does not change */
if (prev_clock_rate) {
val = readl(uart_clock_base->reg2);
divisor = DIV_U64_ROUND_CLOSEST((u64)(val & BRDV_BAUD_MASK) *
parent_clock_rate * prev_d1d2,
prev_clock_rate * d1 * d2);
if (divisor < 1)
divisor = 1;
else if (divisor > BRDV_BAUD_MAX)
divisor = BRDV_BAUD_MAX;
val = (val & ~BRDV_BAUD_MASK) | divisor;
writel(val, uart_clock_base->reg2);
}
uart_clock_base->configured = true;
spin_unlock_irqrestore(&mvebu_uart_lock, flags);
return 0;
}
static int mvebu_uart_clock_enable(struct clk_hw *hw)
{
struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
struct mvebu_uart_clock_base *uart_clock_base =
to_uart_clock_base(uart_clock);
unsigned long flags;
u32 val;
spin_lock_irqsave(&mvebu_uart_lock, flags);
val = readl(uart_clock_base->reg1);
if (uart_clock->clock_idx == 0)
val &= ~UART1_CLK_DIS;
else
val &= ~UART2_CLK_DIS;
writel(val, uart_clock_base->reg1);
spin_unlock_irqrestore(&mvebu_uart_lock, flags);
return 0;
}
static void mvebu_uart_clock_disable(struct clk_hw *hw)
{
struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
struct mvebu_uart_clock_base *uart_clock_base =
to_uart_clock_base(uart_clock);
unsigned long flags;
u32 val;
spin_lock_irqsave(&mvebu_uart_lock, flags);
val = readl(uart_clock_base->reg1);
if (uart_clock->clock_idx == 0)
val |= UART1_CLK_DIS;
else
val |= UART2_CLK_DIS;
writel(val, uart_clock_base->reg1);
spin_unlock_irqrestore(&mvebu_uart_lock, flags);
}
static int mvebu_uart_clock_is_enabled(struct clk_hw *hw)
{
struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
struct mvebu_uart_clock_base *uart_clock_base =
to_uart_clock_base(uart_clock);
u32 val;
val = readl(uart_clock_base->reg1);
if (uart_clock->clock_idx == 0)
return !(val & UART1_CLK_DIS);
else
return !(val & UART2_CLK_DIS);
}
static int mvebu_uart_clock_save_context(struct clk_hw *hw)
{
struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
struct mvebu_uart_clock_base *uart_clock_base =
to_uart_clock_base(uart_clock);
unsigned long flags;
spin_lock_irqsave(&mvebu_uart_lock, flags);
uart_clock->pm_context_reg1 = readl(uart_clock_base->reg1);
uart_clock->pm_context_reg2 = readl(uart_clock_base->reg2);
spin_unlock_irqrestore(&mvebu_uart_lock, flags);
return 0;
}
static void mvebu_uart_clock_restore_context(struct clk_hw *hw)
{
struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
struct mvebu_uart_clock_base *uart_clock_base =
to_uart_clock_base(uart_clock);
unsigned long flags;
spin_lock_irqsave(&mvebu_uart_lock, flags);
writel(uart_clock->pm_context_reg1, uart_clock_base->reg1);
writel(uart_clock->pm_context_reg2, uart_clock_base->reg2);
spin_unlock_irqrestore(&mvebu_uart_lock, flags);
}
static unsigned long mvebu_uart_clock_recalc_rate(struct clk_hw *hw,
unsigned long parent_rate)
{
struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
struct mvebu_uart_clock_base *uart_clock_base =
to_uart_clock_base(uart_clock);
return parent_rate / uart_clock_base->div;
}
static long mvebu_uart_clock_round_rate(struct clk_hw *hw, unsigned long rate,
unsigned long *parent_rate)
{
struct mvebu_uart_clock *uart_clock = to_uart_clock(hw);
struct mvebu_uart_clock_base *uart_clock_base =
to_uart_clock_base(uart_clock);
return *parent_rate / uart_clock_base->div;
}
static int mvebu_uart_clock_set_rate(struct clk_hw *hw, unsigned long rate,
unsigned long parent_rate)
{
/*
* We must report success but we can do so unconditionally because
* mvebu_uart_clock_round_rate returns values that ensure this call is a
* nop.
*/
return 0;
}
static const struct clk_ops mvebu_uart_clock_ops = {
.prepare = mvebu_uart_clock_prepare,
.enable = mvebu_uart_clock_enable,
.disable = mvebu_uart_clock_disable,
.is_enabled = mvebu_uart_clock_is_enabled,
.save_context = mvebu_uart_clock_save_context,
.restore_context = mvebu_uart_clock_restore_context,
.round_rate = mvebu_uart_clock_round_rate,
.set_rate = mvebu_uart_clock_set_rate,
.recalc_rate = mvebu_uart_clock_recalc_rate,
};
static int mvebu_uart_clock_register(struct device *dev,
struct mvebu_uart_clock *uart_clock,
const char *name,
const char *parent_name)
{
struct clk_init_data init = { };
uart_clock->clk_hw.init = &init;
init.name = name;
init.ops = &mvebu_uart_clock_ops;
init.flags = 0;
init.num_parents = 1;
init.parent_names = &parent_name;
return devm_clk_hw_register(dev, &uart_clock->clk_hw);
}
static int mvebu_uart_clock_probe(struct platform_device *pdev)
{
static const char *const uart_clk_names[] = { "uart_1", "uart_2" };
static const char *const parent_clk_names[] = { "TBG-A-P", "TBG-B-P",
"TBG-A-S", "TBG-B-S",
"xtal" };
struct clk *parent_clks[ARRAY_SIZE(parent_clk_names)];
struct mvebu_uart_clock_base *uart_clock_base;
struct clk_hw_onecell_data *hw_clk_data;
struct device *dev = &pdev->dev;
int i, parent_clk_idx, ret;
unsigned long div, rate;
struct resource *res;
unsigned int d1, d2;
BUILD_BUG_ON(ARRAY_SIZE(uart_clk_names) !=
ARRAY_SIZE(uart_clock_base->clocks));
BUILD_BUG_ON(ARRAY_SIZE(parent_clk_names) !=
ARRAY_SIZE(uart_clock_base->parent_rates));
uart_clock_base = devm_kzalloc(dev,
sizeof(*uart_clock_base),
GFP_KERNEL);
if (!uart_clock_base)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
dev_err(dev, "Couldn't get first register\n");
return -ENOENT;
}
/*
* UART Clock Control register (reg1 / UART_BRDV) is in the address
* space of UART1 (standard UART variant), controls parent clock and
* dividers for both UART1 and UART2 and is supplied via DT as the first
* resource. Therefore use ioremap() rather than ioremap_resource() to
* avoid conflicts with UART1 driver. Access to UART_BRDV is protected
* by a lock shared between clock and UART driver.
*/
uart_clock_base->reg1 = devm_ioremap(dev, res->start,
resource_size(res));
if (!uart_clock_base->reg1)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
if (!res) {
dev_err(dev, "Couldn't get second register\n");
return -ENOENT;
}
/*
* UART 2 Baud Rate Divisor register (reg2 / UART_BRDV) is in address
* space of UART2 (extended UART variant), controls only one UART2
* specific divider and is supplied via DT as second resource.
* Therefore use ioremap() rather than ioremap_resource() to avoid
* conflicts with UART2 driver. Access to UART_BRDV is protected by a
* by lock shared between clock and UART driver.
*/
uart_clock_base->reg2 = devm_ioremap(dev, res->start,
resource_size(res));
if (!uart_clock_base->reg2)
return -ENOMEM;
hw_clk_data = devm_kzalloc(dev,
struct_size(hw_clk_data, hws,
ARRAY_SIZE(uart_clk_names)),
GFP_KERNEL);
if (!hw_clk_data)
return -ENOMEM;
hw_clk_data->num = ARRAY_SIZE(uart_clk_names);
for (i = 0; i < ARRAY_SIZE(uart_clk_names); i++) {
hw_clk_data->hws[i] = &uart_clock_base->clocks[i].clk_hw;
uart_clock_base->clocks[i].clock_idx = i;
}
parent_clk_idx = -1;
for (i = 0; i < ARRAY_SIZE(parent_clk_names); i++) {
parent_clks[i] = devm_clk_get(dev, parent_clk_names[i]);
if (IS_ERR(parent_clks[i])) {
if (PTR_ERR(parent_clks[i]) == -EPROBE_DEFER)
return -EPROBE_DEFER;
dev_warn(dev, "Couldn't get the parent clock %s: %ld\n",
parent_clk_names[i], PTR_ERR(parent_clks[i]));
continue;
}
ret = clk_prepare_enable(parent_clks[i]);
if (ret) {
dev_warn(dev, "Couldn't enable parent clock %s: %d\n",
parent_clk_names[i], ret);
continue;
}
rate = clk_get_rate(parent_clks[i]);
uart_clock_base->parent_rates[i] = rate;
if (i != PARENT_CLOCK_XTAL) {
/*
* Calculate the smallest TBG d1 and d2 divisors that
* still can provide 9600 baudrate.
*/
d1 = DIV_ROUND_UP(rate, 9600 * OSAMP_MAX_DIVISOR *
BRDV_BAUD_MAX);
if (d1 < 1)
d1 = 1;
else if (d1 > CLK_TBG_DIV1_MAX)
d1 = CLK_TBG_DIV1_MAX;
d2 = DIV_ROUND_UP(rate, 9600 * OSAMP_MAX_DIVISOR *
BRDV_BAUD_MAX * d1);
if (d2 < 1)
d2 = 1;
else if (d2 > CLK_TBG_DIV2_MAX)
d2 = CLK_TBG_DIV2_MAX;
} else {
/*
* When UART clock uses XTAL clock as a source then it
* is not possible to use d1 and d2 divisors.
*/
d1 = d2 = 1;
}
/* Skip clock source which cannot provide 9600 baudrate */
if (rate > 9600 * OSAMP_MAX_DIVISOR * BRDV_BAUD_MAX * d1 * d2)
continue;
/*
* Choose TBG clock source with the smallest divisors. Use XTAL
* clock source only in case TBG is not available as XTAL cannot
* be used for baudrates higher than 230400.
*/
if (parent_clk_idx == -1 ||
(i != PARENT_CLOCK_XTAL && div > d1 * d2)) {
parent_clk_idx = i;
div = d1 * d2;
}
}
for (i = 0; i < ARRAY_SIZE(parent_clk_names); i++) {
if (i == parent_clk_idx || IS_ERR(parent_clks[i]))
continue;
clk_disable_unprepare(parent_clks[i]);
devm_clk_put(dev, parent_clks[i]);
}
if (parent_clk_idx == -1) {
dev_err(dev, "No usable parent clock\n");
return -ENOENT;
}
uart_clock_base->parent_idx = parent_clk_idx;
uart_clock_base->div = div;
dev_notice(dev, "Using parent clock %s as base UART clock\n",
__clk_get_name(parent_clks[parent_clk_idx]));
for (i = 0; i < ARRAY_SIZE(uart_clk_names); i++) {
ret = mvebu_uart_clock_register(dev,
&uart_clock_base->clocks[i],
uart_clk_names[i],
__clk_get_name(parent_clks[parent_clk_idx]));
if (ret) {
dev_err(dev, "Can't register UART clock %d: %d\n",
i, ret);
return ret;
}
}
return devm_of_clk_add_hw_provider(dev, of_clk_hw_onecell_get,
hw_clk_data);
}
static const struct of_device_id mvebu_uart_clock_of_match[] = {
{ .compatible = "marvell,armada-3700-uart-clock", },
{ }
};
static struct platform_driver mvebu_uart_clock_platform_driver = {
.probe = mvebu_uart_clock_probe,
.driver = {
.name = "mvebu-uart-clock",
.of_match_table = mvebu_uart_clock_of_match,
},
};
static int __init mvebu_uart_init(void)
{
int ret;
ret = uart_register_driver(&mvebu_uart_driver);
if (ret)
return ret;
ret = platform_driver_register(&mvebu_uart_clock_platform_driver);
if (ret) {
uart_unregister_driver(&mvebu_uart_driver);
return ret;
}
ret = platform_driver_register(&mvebu_uart_platform_driver);
if (ret) {
platform_driver_unregister(&mvebu_uart_clock_platform_driver);
uart_unregister_driver(&mvebu_uart_driver);
return ret;
}
return 0;
}
arch_initcall(mvebu_uart_init);
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