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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2015-2016 Wills Wang <wills.wang@live.com>
*/
#include <clock_legacy.h>
#include <dm.h>
#include <div64.h>
#include <errno.h>
#include <serial.h>
#include <asm/io.h>
#include <asm/addrspace.h>
#include <asm/types.h>
#include <dm/pinctrl.h>
#include <linux/bitops.h>
#include <mach/ar71xx_regs.h>
#define AR933X_UART_DATA_REG 0x00
#define AR933X_UART_CS_REG 0x04
#define AR933X_UART_CLK_REG 0x08
#define AR933X_UART_DATA_TX_RX_MASK 0xff
#define AR933X_UART_DATA_RX_CSR BIT(8)
#define AR933X_UART_DATA_TX_CSR BIT(9)
#define AR933X_UART_CS_IF_MODE_S 2
#define AR933X_UART_CS_IF_MODE_M 0x3
#define AR933X_UART_CS_IF_MODE_DTE 1
#define AR933X_UART_CS_IF_MODE_DCE 2
#define AR933X_UART_CS_TX_RDY_ORIDE BIT(7)
#define AR933X_UART_CS_RX_RDY_ORIDE BIT(8)
#define AR933X_UART_CLK_STEP_M 0xffff
#define AR933X_UART_CLK_SCALE_M 0xfff
#define AR933X_UART_CLK_SCALE_S 16
#define AR933X_UART_CLK_STEP_S 0
struct ar933x_serial_priv {
void __iomem *regs;
};
/*
* Baudrate algorithm come from Linux/drivers/tty/serial/ar933x_uart.c
* baudrate = (clk / (scale + 1)) * (step * (1 / 2^17))
*/
static u32 ar933x_serial_get_baud(u32 clk, u32 scale, u32 step)
{
u64 t;
u32 div;
div = (2 << 16) * (scale + 1);
t = clk;
t *= step;
t += (div / 2);
do_div(t, div);
return t;
}
static void ar933x_serial_get_scale_step(u32 clk, u32 baud,
u32 *scale, u32 *step)
{
u32 tscale, baudrate;
long min_diff;
*scale = 0;
*step = 0;
min_diff = baud;
for (tscale = 0; tscale < AR933X_UART_CLK_SCALE_M; tscale++) {
u64 tstep;
int diff;
tstep = baud * (tscale + 1);
tstep *= (2 << 16);
do_div(tstep, clk);
if (tstep > AR933X_UART_CLK_STEP_M)
break;
baudrate = ar933x_serial_get_baud(clk, tscale, tstep);
diff = abs(baudrate - baud);
if (diff < min_diff) {
min_diff = diff;
*scale = tscale;
*step = tstep;
}
}
}
static int ar933x_serial_setbrg(struct udevice *dev, int baudrate)
{
struct ar933x_serial_priv *priv = dev_get_priv(dev);
u32 val, scale, step;
val = get_serial_clock();
ar933x_serial_get_scale_step(val, baudrate, &scale, &step);
val = (scale & AR933X_UART_CLK_SCALE_M)
<< AR933X_UART_CLK_SCALE_S;
val |= (step & AR933X_UART_CLK_STEP_M)
<< AR933X_UART_CLK_STEP_S;
writel(val, priv->regs + AR933X_UART_CLK_REG);
return 0;
}
static int ar933x_serial_putc(struct udevice *dev, const char c)
{
struct ar933x_serial_priv *priv = dev_get_priv(dev);
u32 data;
data = readl(priv->regs + AR933X_UART_DATA_REG);
if (!(data & AR933X_UART_DATA_TX_CSR))
return -EAGAIN;
data = (u32)c | AR933X_UART_DATA_TX_CSR;
writel(data, priv->regs + AR933X_UART_DATA_REG);
return 0;
}
static int ar933x_serial_getc(struct udevice *dev)
{
struct ar933x_serial_priv *priv = dev_get_priv(dev);
u32 data;
data = readl(priv->regs + AR933X_UART_DATA_REG);
if (!(data & AR933X_UART_DATA_RX_CSR))
return -EAGAIN;
writel(AR933X_UART_DATA_RX_CSR, priv->regs + AR933X_UART_DATA_REG);
return data & AR933X_UART_DATA_TX_RX_MASK;
}
static int ar933x_serial_pending(struct udevice *dev, bool input)
{
struct ar933x_serial_priv *priv = dev_get_priv(dev);
u32 data;
data = readl(priv->regs + AR933X_UART_DATA_REG);
if (input)
return (data & AR933X_UART_DATA_RX_CSR) ? 1 : 0;
else
return (data & AR933X_UART_DATA_TX_CSR) ? 0 : 1;
}
static int ar933x_serial_probe(struct udevice *dev)
{
struct ar933x_serial_priv *priv = dev_get_priv(dev);
fdt_addr_t addr;
u32 val;
addr = dev_read_addr(dev);
if (addr == FDT_ADDR_T_NONE)
return -EINVAL;
priv->regs = map_physmem(addr, AR933X_UART_SIZE,
MAP_NOCACHE);
/*
* UART controller configuration:
* - no DMA
* - no interrupt
* - DCE mode
* - no flow control
* - set RX ready oride
* - set TX ready oride
*/
val = (AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S) |
AR933X_UART_CS_TX_RDY_ORIDE | AR933X_UART_CS_RX_RDY_ORIDE;
writel(val, priv->regs + AR933X_UART_CS_REG);
return 0;
}
static const struct dm_serial_ops ar933x_serial_ops = {
.putc = ar933x_serial_putc,
.pending = ar933x_serial_pending,
.getc = ar933x_serial_getc,
.setbrg = ar933x_serial_setbrg,
};
static const struct udevice_id ar933x_serial_ids[] = {
{ .compatible = "qca,ar9330-uart" },
{ }
};
U_BOOT_DRIVER(serial_ar933x) = {
.name = "serial_ar933x",
.id = UCLASS_SERIAL,
.of_match = ar933x_serial_ids,
.priv_auto = sizeof(struct ar933x_serial_priv),
.probe = ar933x_serial_probe,
.ops = &ar933x_serial_ops,
};
#ifdef CONFIG_DEBUG_UART_AR933X
#include <debug_uart.h>
static inline void _debug_uart_init(void)
{
void __iomem *regs = (void *)CONFIG_VAL(DEBUG_UART_BASE);
u32 val, scale, step;
/*
* UART controller configuration:
* - no DMA
* - no interrupt
* - DCE mode
* - no flow control
* - set RX ready oride
* - set TX ready oride
*/
val = (AR933X_UART_CS_IF_MODE_DCE << AR933X_UART_CS_IF_MODE_S) |
AR933X_UART_CS_TX_RDY_ORIDE | AR933X_UART_CS_RX_RDY_ORIDE;
writel(val, regs + AR933X_UART_CS_REG);
ar933x_serial_get_scale_step(CONFIG_DEBUG_UART_CLOCK,
CONFIG_BAUDRATE, &scale, &step);
val = (scale & AR933X_UART_CLK_SCALE_M)
<< AR933X_UART_CLK_SCALE_S;
val |= (step & AR933X_UART_CLK_STEP_M)
<< AR933X_UART_CLK_STEP_S;
writel(val, regs + AR933X_UART_CLK_REG);
}
static inline void _debug_uart_putc(int c)
{
void __iomem *regs = (void *)CONFIG_VAL(DEBUG_UART_BASE);
u32 data;
do {
data = readl(regs + AR933X_UART_DATA_REG);
} while (!(data & AR933X_UART_DATA_TX_CSR));
data = (u32)c | AR933X_UART_DATA_TX_CSR;
writel(data, regs + AR933X_UART_DATA_REG);
}
DEBUG_UART_FUNCS
#endif
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