This patch adds support to ASC (asynchronous serial controller) driver, which is basically a standard serial driver. This IP is common across other STMicroelectronics SoCs Signed-off-by: Patrice Chotard <patrice.chotard@st.com> Reviewed-by: Simon Glass <sjg@chromium.org>master
parent
413788cef5
commit
214a17e61d
@ -0,0 +1,211 @@ |
||||
/*
|
||||
* Support for Serial I/O using STMicroelectronics' on-chip ASC. |
||||
* |
||||
* Copyright (c) 2017 |
||||
* Patrice Chotard <patrice.chotard@st.com> |
||||
* |
||||
* SPDX-License-Identifier: GPL-2.0 |
||||
*/ |
||||
|
||||
#include <common.h> |
||||
#include <dm.h> |
||||
#include <serial.h> |
||||
#include <asm/io.h> |
||||
|
||||
DECLARE_GLOBAL_DATA_PTR; |
||||
|
||||
#define BAUDMODE 0x00001000 |
||||
#define RXENABLE 0x00000100 |
||||
#define RUN 0x00000080 |
||||
#define MODE 0x00000001 |
||||
#define MODE_8BIT 0x0001 |
||||
#define STOP_1BIT 0x0008 |
||||
#define PARITYODD 0x0020 |
||||
|
||||
#define STA_TF BIT(9) |
||||
#define STA_RBF BIT(0) |
||||
|
||||
struct sti_asc_uart { |
||||
u32 baudrate; |
||||
u32 txbuf; |
||||
u32 rxbuf; |
||||
u32 control; |
||||
u32 inten; |
||||
u32 status; |
||||
u32 guardtime; |
||||
u32 timeout; |
||||
u32 txreset; |
||||
u32 rxreset; |
||||
}; |
||||
|
||||
struct sti_asc_serial { |
||||
/* address of registers in physical memory */ |
||||
struct sti_asc_uart *regs; |
||||
}; |
||||
|
||||
/* Values for the BAUDRATE Register */ |
||||
#define PCLK (200ul * 1000000ul) |
||||
#define BAUDRATE_VAL_M0(bps) (PCLK / (16 * (bps))) |
||||
#define BAUDRATE_VAL_M1(bps) ((bps * (1 << 14)) + (1<<13)) / (PCLK/(1 << 6)) |
||||
|
||||
/*
|
||||
* MODE 0 |
||||
* ICCLK |
||||
* ASCBaudRate = ---------------- |
||||
* baudrate * 16 |
||||
* |
||||
* MODE 1 |
||||
* baudrate * 16 * 2^16 |
||||
* ASCBaudRate = ------------------------ |
||||
* ICCLK |
||||
* |
||||
* NOTE: |
||||
* Mode 1 should be used for baudrates of 19200, and above, as it |
||||
* has a lower deviation error than Mode 0 for higher frequencies. |
||||
* Mode 0 should be used for all baudrates below 19200. |
||||
*/ |
||||
|
||||
static int sti_asc_pending(struct udevice *dev, bool input) |
||||
{ |
||||
struct sti_asc_serial *priv = dev_get_priv(dev); |
||||
struct sti_asc_uart *const uart = priv->regs; |
||||
unsigned long status; |
||||
|
||||
status = readl(&uart->status); |
||||
if (input) |
||||
return status & STA_RBF; |
||||
else |
||||
return status & STA_TF; |
||||
} |
||||
|
||||
static int _sti_asc_serial_setbrg(struct sti_asc_uart *uart, int baudrate) |
||||
{ |
||||
unsigned long val; |
||||
int t, mode = 1; |
||||
|
||||
switch (baudrate) { |
||||
case 9600: |
||||
t = BAUDRATE_VAL_M0(9600); |
||||
mode = 0; |
||||
break; |
||||
case 19200: |
||||
t = BAUDRATE_VAL_M1(19200); |
||||
break; |
||||
case 38400: |
||||
t = BAUDRATE_VAL_M1(38400); |
||||
break; |
||||
case 57600: |
||||
t = BAUDRATE_VAL_M1(57600); |
||||
break; |
||||
default: |
||||
debug("ASC: unsupported baud rate: %d, using 115200 instead.\n", |
||||
baudrate); |
||||
case 115200: |
||||
t = BAUDRATE_VAL_M1(115200); |
||||
break; |
||||
} |
||||
|
||||
/* disable the baudrate generator */ |
||||
val = readl(&uart->control); |
||||
writel(val & ~RUN, &uart->control); |
||||
|
||||
/* set baud generator reload value */ |
||||
writel(t, &uart->baudrate); |
||||
/* reset the RX & TX buffers */ |
||||
writel(1, &uart->txreset); |
||||
writel(1, &uart->rxreset); |
||||
|
||||
/* set baud generator mode */ |
||||
if (mode) |
||||
val |= BAUDMODE; |
||||
|
||||
/* finally, write value and enable ASC */ |
||||
writel(val, &uart->control); |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
/* called to adjust baud-rate */ |
||||
static int sti_asc_serial_setbrg(struct udevice *dev, int baudrate) |
||||
{ |
||||
struct sti_asc_serial *priv = dev_get_priv(dev); |
||||
struct sti_asc_uart *const uart = priv->regs; |
||||
|
||||
return _sti_asc_serial_setbrg(uart, baudrate); |
||||
} |
||||
|
||||
/* blocking function, that returns next char */ |
||||
static int sti_asc_serial_getc(struct udevice *dev) |
||||
{ |
||||
struct sti_asc_serial *priv = dev_get_priv(dev); |
||||
struct sti_asc_uart *const uart = priv->regs; |
||||
|
||||
/* polling wait: for a char to be read */ |
||||
if (!sti_asc_pending(dev, true)) |
||||
return -EAGAIN; |
||||
|
||||
return readl(&uart->rxbuf); |
||||
} |
||||
|
||||
/* write write out a single char */ |
||||
static int sti_asc_serial_putc(struct udevice *dev, const char c) |
||||
{ |
||||
struct sti_asc_serial *priv = dev_get_priv(dev); |
||||
struct sti_asc_uart *const uart = priv->regs; |
||||
|
||||
/* wait till safe to write next char */ |
||||
if (sti_asc_pending(dev, false)) |
||||
return -EAGAIN; |
||||
|
||||
/* finally, write next char */ |
||||
writel(c, &uart->txbuf); |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
/* initialize the ASC */ |
||||
static int sti_asc_serial_probe(struct udevice *dev) |
||||
{ |
||||
struct sti_asc_serial *priv = dev_get_priv(dev); |
||||
unsigned long val; |
||||
fdt_addr_t base; |
||||
|
||||
base = dev_get_addr(dev); |
||||
if (base == FDT_ADDR_T_NONE) |
||||
return -EINVAL; |
||||
|
||||
priv->regs = (struct sti_asc_uart *)base; |
||||
sti_asc_serial_setbrg(dev, gd->baudrate); |
||||
|
||||
/*
|
||||
* build up the value to be written to CONTROL |
||||
* set character length, bit stop number, odd parity |
||||
*/ |
||||
val = RXENABLE | RUN | MODE_8BIT | STOP_1BIT | PARITYODD; |
||||
writel(val, &priv->regs->control); |
||||
|
||||
return 0; |
||||
} |
||||
|
||||
static const struct dm_serial_ops sti_asc_serial_ops = { |
||||
.putc = sti_asc_serial_putc, |
||||
.pending = sti_asc_pending, |
||||
.getc = sti_asc_serial_getc, |
||||
.setbrg = sti_asc_serial_setbrg, |
||||
}; |
||||
|
||||
static const struct udevice_id sti_serial_of_match[] = { |
||||
{ .compatible = "st,asc" }, |
||||
{ } |
||||
}; |
||||
|
||||
U_BOOT_DRIVER(serial_sti_asc) = { |
||||
.name = "serial_sti_asc", |
||||
.id = UCLASS_SERIAL, |
||||
.of_match = sti_serial_of_match, |
||||
.ops = &sti_asc_serial_ops, |
||||
.probe = sti_asc_serial_probe, |
||||
.priv_auto_alloc_size = sizeof(struct sti_asc_serial), |
||||
.flags = DM_FLAG_PRE_RELOC, |
||||
}; |
||||
|
Loading…
Reference in new issue