diff options
Diffstat (limited to 'drivers/serial/serial_ar933x.c')
| -rw-r--r-- | drivers/serial/serial_ar933x.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/drivers/serial/serial_ar933x.c b/drivers/serial/serial_ar933x.c new file mode 100644 index 0000000000..aae66dc682 --- /dev/null +++ b/drivers/serial/serial_ar933x.c @@ -0,0 +1,243 @@ +/* + * Copyright (C) 2015-2016 Wills Wang <wills.wang@live.com> + * + * SPDX-License-Identifier: GPL-2.0+ + */ + +#include <common.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 <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_get_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_alloc_size = sizeof(struct ar933x_serial_priv), + .probe = ar933x_serial_probe, + .ops = &ar933x_serial_ops, + .flags = DM_FLAG_PRE_RELOC, +}; + +#ifdef CONFIG_DEBUG_UART_AR933X + +#include <debug_uart.h> + +static inline void _debug_uart_init(void) +{ + void __iomem *regs = (void *)CONFIG_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_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 |
