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/*
* Synopsys DesignWare 8250 driver.
*
* Copyright 2011 Picochip, Jamie Iles.
* Copyright 2013 Intel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* The Synopsys DesignWare 8250 has an extra feature whereby it detects if the
* LCR is written whilst busy. If it is, then a busy detect interrupt is
* raised, the LCR needs to be rewritten and the uart status register read.
*/
#include <linux/device.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/serial_8250.h>
#include <linux/serial_reg.h>
#include <linux/of.h>
#include <linux/of_irq.h>
#include <linux/of_platform.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/clk.h>
#include <linux/reset.h>
#include <linux/pm_runtime.h>
#include <asm/byteorder.h>
#include "8250.h"
/* Offsets for the DesignWare specific registers */
#define DW_UART_USR 0x1f /* UART Status Register */
#define DW_UART_CPR 0xf4 /* Component Parameter Register */
#define DW_UART_UCV 0xf8 /* UART Component Version */
/* Component Parameter Register bits */
#define DW_UART_CPR_ABP_DATA_WIDTH (3 << 0)
#define DW_UART_CPR_AFCE_MODE (1 << 4)
#define DW_UART_CPR_THRE_MODE (1 << 5)
#define DW_UART_CPR_SIR_MODE (1 << 6)
#define DW_UART_CPR_SIR_LP_MODE (1 << 7)
#define DW_UART_CPR_ADDITIONAL_FEATURES (1 << 8)
#define DW_UART_CPR_FIFO_ACCESS (1 << 9)
#define DW_UART_CPR_FIFO_STAT (1 << 10)
#define DW_UART_CPR_SHADOW (1 << 11)
#define DW_UART_CPR_ENCODED_PARMS (1 << 12)
#define DW_UART_CPR_DMA_EXTRA (1 << 13)
#define DW_UART_CPR_FIFO_MODE (0xff << 16)
/* Helper for fifo size calculation */
#define DW_UART_CPR_FIFO_SIZE(a) (((a >> 16) & 0xff) * 16)
struct dw8250_data {
u8 usr_reg;
int last_mcr;
int line;
int msr_mask_on;
int msr_mask_off;
struct clk *clk;
struct clk *pclk;
struct reset_control *rst;
struct uart_8250_dma dma;
};
#define BYT_PRV_CLK 0x800
#define BYT_PRV_CLK_EN (1 << 0)
#define BYT_PRV_CLK_M_VAL_SHIFT 1
#define BYT_PRV_CLK_N_VAL_SHIFT 16
#define BYT_PRV_CLK_UPDATE (1 << 31)
static inline int dw8250_modify_msr(struct uart_port *p, int offset, int value)
{
struct dw8250_data *d = p->private_data;
/* If reading MSR, report CTS asserted when auto-CTS/RTS enabled */
if (offset == UART_MSR && d->last_mcr & UART_MCR_AFE) {
value |= UART_MSR_CTS;
value &= ~UART_MSR_DCTS;
}
/* Override any modem control signals if needed */
if (offset == UART_MSR) {
value |= d->msr_mask_on;
value &= ~d->msr_mask_off;
}
return value;
}
static void dw8250_force_idle(struct uart_port *p)
{
struct uart_8250_port *up = up_to_u8250p(p);
serial8250_clear_and_reinit_fifos(up);
(void)p->serial_in(p, UART_RX);
}
static void dw8250_serial_out(struct uart_port *p, int offset, int value)
{
struct dw8250_data *d = p->private_data;
if (offset == UART_MCR)
d->last_mcr = value;
writeb(value, p->membase + (offset << p->regshift));
/* Make sure LCR write wasn't ignored */
if (offset == UART_LCR) {
int tries = 1000;
while (tries--) {
unsigned int lcr = p->serial_in(p, UART_LCR);
if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
return;
dw8250_force_idle(p);
writeb(value, p->membase + (UART_LCR << p->regshift));
}
/*
* FIXME: this deadlocks if port->lock is already held
* dev_err(p->dev, "Couldn't set LCR to %d\n", value);
*/
}
}
static unsigned int dw8250_serial_in(struct uart_port *p, int offset)
{
unsigned int value = readb(p->membase + (offset << p->regshift));
return dw8250_modify_msr(p, offset, value);
}
#ifdef CONFIG_64BIT
static unsigned int dw8250_serial_inq(struct uart_port *p, int offset)
{
unsigned int value;
value = (u8)__raw_readq(p->membase + (offset << p->regshift));
return dw8250_modify_msr(p, offset, value);
}
static void dw8250_serial_outq(struct uart_port *p, int offset, int value)
{
struct dw8250_data *d = p->private_data;
if (offset == UART_MCR)
d->last_mcr = value;
value &= 0xff;
__raw_writeq(value, p->membase + (offset << p->regshift));
/* Read back to ensure register write ordering. */
__raw_readq(p->membase + (UART_LCR << p->regshift));
/* Make sure LCR write wasn't ignored */
if (offset == UART_LCR) {
int tries = 1000;
while (tries--) {
unsigned int lcr = p->serial_in(p, UART_LCR);
if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
return;
dw8250_force_idle(p);
__raw_writeq(value & 0xff,
p->membase + (UART_LCR << p->regshift));
}
/*
* FIXME: this deadlocks if port->lock is already held
* dev_err(p->dev, "Couldn't set LCR to %d\n", value);
*/
}
}
#endif /* CONFIG_64BIT */
static void dw8250_serial_out32(struct uart_port *p, int offset, int value)
{
struct dw8250_data *d = p->private_data;
if (offset == UART_MCR)
d->last_mcr = value;
writel(value, p->membase + (offset << p->regshift));
/* Make sure LCR write wasn't ignored */
if (offset == UART_LCR) {
int tries = 1000;
while (tries--) {
unsigned int lcr = p->serial_in(p, UART_LCR);
if ((value & ~UART_LCR_SPAR) == (lcr & ~UART_LCR_SPAR))
return;
dw8250_force_idle(p);
writel(value, p->membase + (UART_LCR << p->regshift));
}
/*
* FIXME: this deadlocks if port->lock is already held
* dev_err(p->dev, "Couldn't set LCR to %d\n", value);
*/
}
}
static unsigned int dw8250_serial_in32(struct uart_port *p, int offset)
{
unsigned int value = readl(p->membase + (offset << p->regshift));
return dw8250_modify_msr(p, offset, value);
}
static int dw8250_handle_irq(struct uart_port *p)
{
struct dw8250_data *d = p->private_data;
unsigned int iir = p->serial_in(p, UART_IIR);
if (serial8250_handle_irq(p, iir)) {
return 1;
} else if ((iir & UART_IIR_BUSY) == UART_IIR_BUSY) {
/* Clear the USR */
(void)p->serial_in(p, d->usr_reg);
return 1<
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