[U-Boot] [PATCH v4 4/8] mips: ath79: add serial driver for ar933x SOC

[Daniel Schwierzeck <daniel.schwierzeck@gmail.com>]

Am 25.12.2015 um 19:56 schrieb Wills Wang:
> Signed-off-by: Wills Wang <wills.wang@live.com>
> ---
> 
> Changes in v4: None
> Changes in v3: None
> Changes in v2: None
> 
>  drivers/serial/Makefile        |   1 +
>  drivers/serial/serial_ar933x.c | 225 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 226 insertions(+)
>  create mode 100644 drivers/serial/serial_ar933x.c
> 
> diff --git a/drivers/serial/Makefile b/drivers/serial/Makefile
> index dd87147..9a7ad89 100644
> --- a/drivers/serial/Makefile
> +++ b/drivers/serial/Makefile
> @@ -17,6 +17,7 @@ endif
>  
>  obj-$(CONFIG_ALTERA_UART) += altera_uart.o
>  obj-$(CONFIG_ALTERA_JTAG_UART) += altera_jtag_uart.o
> +obj-$(CONFIG_AR933X_SERIAL) += serial_ar933x.o
>  obj-$(CONFIG_ARM_DCC) += arm_dcc.o
>  obj-$(CONFIG_ATMEL_USART) += atmel_usart.o
>  obj-$(CONFIG_EFI_APP) += serial_efi.o
> diff --git a/drivers/serial/serial_ar933x.c b/drivers/serial/serial_ar933x.c
> new file mode 100644
> index 0000000..efca93c
> --- /dev/null
> +++ b/drivers/serial/serial_ar933x.c
> @@ -0,0 +1,225 @@
> +/*
> + * (C) Copyright 2015
> + * Wills Wang, <wills.wang@live.com>
> + *
> + * SPDX-License-Identifier: GPL-2.0+
> + */
> +
> +#include <common.h>
> +#include <dm.h>
> +#include <errno.h>
> +#include <serial.h>
> +#include <asm/io.h>
> +#include <asm/addrspace.h>
> +#include <asm/div64.h>

use the existing and generic implementation in include/div64.h

> +#include <asm/types.h>
> +#include <asm/arch/ar71xx_regs.h>

#include <mach/ar71xx_regs.h>

I wonder how you can stil compile your code


> +
> +DECLARE_GLOBAL_DATA_PTR;
> +
> +#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_platdata {
> +	void __iomem *regs;
> +};

if you always support device-tree, you do not need platform data

> +
> +struct ar933x_serial_priv {
> +	void __iomem *regs;
> +};
> +
> +static inline u32 ar933x_serial_read(struct udevice *dev, u32 offset)
> +{
> +	struct ar933x_serial_priv *priv = dev_get_priv(dev);
> +	return readl(priv->regs + offset);
> +}
> +
> +static inline void ar933x_serial_write(struct udevice *dev,
> +					u32 val, u32 offset)
> +{
> +	struct ar933x_serial_priv *priv = dev_get_priv(dev);
> +	writel(val, priv->regs + offset);
> +}
> +
> +/*
> + * 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)
> +{
> +	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;
> +	ar933x_serial_write(dev, val, AR933X_UART_CLK_REG);
> +
> +	return 0;
> +}
> +
> +static int ar933x_serial_putc(struct udevice *dev, const char c)
> +{
> +	u32 data;
> +
> +	if (c == '\n')
> +		ar933x_serial_putc(dev, '\r');

remove this, the serial core driver takes care of it

> +
> +	do {
> +		data = ar933x_serial_read(dev, AR933X_UART_DATA_REG);
> +	} while (!(data & AR933X_UART_DATA_TX_CSR));

remove this, the serial core driver takes care of it via your pending
callback (ar933x_serial_pending)

> +
> +	data  = (u32)c | AR933X_UART_DATA_TX_CSR;
> +	ar933x_serial_write(dev, data, AR933X_UART_DATA_REG);
> +
> +	return 0;
> +}
> +
> +static int ar933x_serial_getc(struct udevice *dev)
> +{
> +	u32 data;
> +
> +	do {
> +		data = ar933x_serial_read(dev, AR933X_UART_DATA_REG);
> +	} while (!(data & AR933X_UART_DATA_RX_CSR));

dito

> +
> +	data = ar933x_serial_read(dev, AR933X_UART_DATA_REG);
> +	ar933x_serial_write(dev, AR933X_UART_DATA_RX_CSR,
> +			    AR933X_UART_DATA_REG);
> +	return data & AR933X_UART_DATA_TX_RX_MASK;
> +}
> +
> +static int ar933x_serial_pending(struct udevice *dev, bool input)
> +{
> +	u32 data;
> +
> +	data = ar933x_serial_read(dev, 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);
> +	struct ar933x_serial_platdata *plat = dev_get_platdata(dev);
> +	u32 val;
> +
> +	priv->regs = plat->regs;
> +
> +	/*
> +	 * 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;
> +	ar933x_serial_write(dev, val, AR933X_UART_CS_REG);
> +	return 0;
> +}
> +
> +static int ar933x_serial_ofdata_to_platdata(struct udevice *dev)
> +{
> +	struct ar933x_serial_platdata *plat = dev_get_platdata(dev);
> +	fdt_addr_t addr;
> +
> +	addr = dev_get_addr(dev);
> +	if (addr == FDT_ADDR_T_NONE)
> +		return -EINVAL;
> +
> +	plat->regs = map_physmem(addr,
> +				 AR933X_UART_SIZE,
> +				 MAP_NOCACHE);

move this code to function ar933x_serial_probe and drop this function

> +	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 = "ath79,ar933x-uart" },
> +	{ }
> +};
> +
> +U_BOOT_DRIVER(serial_ar933x) = {
> +	.name   = "serial_ar933x",
> +	.id = UCLASS_SERIAL,
> +	.of_match = ar933x_serial_ids,
> +	.ofdata_to_platdata = ar933x_serial_ofdata_to_platdata,
> +	.platdata_auto_alloc_size = sizeof(struct ar933x_serial_platdata),

drop the two lines, you do not need to allocate platdata

> +	.priv_auto_alloc_size = sizeof(struct ar933x_serial_priv),
> +	.probe = ar933x_serial_probe,
> +	.ops    = &ar933x_serial_ops,
> +	.flags = DM_FLAG_PRE_RELOC,
> +};
> 

-- 
- Daniel