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199 lines
4.6 KiB
199 lines
4.6 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* (c) 2015 Paul Thacker <[email protected]> |
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* |
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*/ |
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#include <common.h> |
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#include <clk.h> |
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#include <dm.h> |
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#include <serial.h> |
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#include <wait_bit.h> |
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#include <mach/pic32.h> |
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#include <dt-bindings/clock/microchip,clock.h> |
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DECLARE_GLOBAL_DATA_PTR; |
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/* UART Control Registers */ |
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#define U_MOD 0x00 |
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#define U_MODCLR (U_MOD + _CLR_OFFSET) |
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#define U_MODSET (U_MOD + _SET_OFFSET) |
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#define U_STA 0x10 |
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#define U_STACLR (U_STA + _CLR_OFFSET) |
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#define U_STASET (U_STA + _SET_OFFSET) |
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#define U_TXR 0x20 |
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#define U_RXR 0x30 |
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#define U_BRG 0x40 |
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/* U_MOD bits */ |
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#define UART_ENABLE BIT(15) |
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/* U_STA bits */ |
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#define UART_RX_ENABLE BIT(12) |
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#define UART_TX_BRK BIT(11) |
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#define UART_TX_ENABLE BIT(10) |
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#define UART_TX_FULL BIT(9) |
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#define UART_TX_EMPTY BIT(8) |
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#define UART_RX_OVER BIT(1) |
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#define UART_RX_DATA_AVAIL BIT(0) |
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struct pic32_uart_priv { |
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void __iomem *base; |
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ulong uartclk; |
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}; |
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/* |
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* Initialize the serial port with the given baudrate. |
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* The settings are always 8 data bits, no parity, 1 stop bit, no start bits. |
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*/ |
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static int pic32_serial_init(void __iomem *base, ulong clk, u32 baudrate) |
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{ |
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u32 div = DIV_ROUND_CLOSEST(clk, baudrate * 16); |
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/* wait for TX FIFO to empty */ |
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wait_for_bit_le32(base + U_STA, UART_TX_EMPTY, |
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true, CONFIG_SYS_HZ, false); |
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/* send break */ |
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writel(UART_TX_BRK, base + U_STASET); |
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/* disable and clear mode */ |
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writel(0, base + U_MOD); |
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writel(0, base + U_STA); |
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/* set baud rate generator */ |
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writel(div - 1, base + U_BRG); |
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/* enable the UART for TX and RX */ |
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writel(UART_TX_ENABLE | UART_RX_ENABLE, base + U_STASET); |
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/* enable the UART */ |
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writel(UART_ENABLE, base + U_MODSET); |
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return 0; |
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} |
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/* Check whether any char pending in RX fifo */ |
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static int pic32_uart_pending_input(void __iomem *base) |
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{ |
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/* check if rx buffer overrun error has occurred */ |
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if (readl(base + U_STA) & UART_RX_OVER) { |
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readl(base + U_RXR); |
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/* clear overrun error to keep receiving */ |
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writel(UART_RX_OVER, base + U_STACLR); |
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} |
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/* In PIC32 there is no way to know number of outstanding |
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* chars in rx-fifo. Only it can be known whether there is any. |
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*/ |
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return readl(base + U_STA) & UART_RX_DATA_AVAIL; |
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} |
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static int pic32_uart_pending(struct udevice *dev, bool input) |
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{ |
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struct pic32_uart_priv *priv = dev_get_priv(dev); |
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if (input) |
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return pic32_uart_pending_input(priv->base); |
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return !(readl(priv->base + U_STA) & UART_TX_EMPTY); |
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} |
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static int pic32_uart_setbrg(struct udevice *dev, int baudrate) |
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{ |
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struct pic32_uart_priv *priv = dev_get_priv(dev); |
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return pic32_serial_init(priv->base, priv->uartclk, baudrate); |
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} |
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static int pic32_uart_putc(struct udevice *dev, const char ch) |
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{ |
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struct pic32_uart_priv *priv = dev_get_priv(dev); |
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/* Check if Tx FIFO is full */ |
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if (readl(priv->base + U_STA) & UART_TX_FULL) |
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return -EAGAIN; |
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/* pump the char to tx buffer */ |
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writel(ch, priv->base + U_TXR); |
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return 0; |
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} |
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static int pic32_uart_getc(struct udevice *dev) |
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{ |
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struct pic32_uart_priv *priv = dev_get_priv(dev); |
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/* return error if RX fifo is empty */ |
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if (!pic32_uart_pending_input(priv->base)) |
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return -EAGAIN; |
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/* read the character from rx buffer */ |
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return readl(priv->base + U_RXR) & 0xff; |
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} |
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static int pic32_uart_probe(struct udevice *dev) |
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{ |
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struct pic32_uart_priv *priv = dev_get_priv(dev); |
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struct clk clk; |
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fdt_addr_t addr; |
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fdt_size_t size; |
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int ret; |
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/* get address */ |
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addr = fdtdec_get_addr_size(gd->fdt_blob, dev_of_offset(dev), "reg", |
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&size); |
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if (addr == FDT_ADDR_T_NONE) |
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return -EINVAL; |
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priv->base = ioremap(addr, size); |
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/* get clock rate */ |
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ret = clk_get_by_index(dev, 0, &clk); |
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if (ret < 0) |
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return ret; |
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priv->uartclk = clk_get_rate(&clk); |
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clk_free(&clk); |
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/* initialize serial */ |
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return pic32_serial_init(priv->base, priv->uartclk, CONFIG_BAUDRATE); |
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} |
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static const struct dm_serial_ops pic32_uart_ops = { |
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.putc = pic32_uart_putc, |
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.pending = pic32_uart_pending, |
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.getc = pic32_uart_getc, |
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.setbrg = pic32_uart_setbrg, |
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}; |
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static const struct udevice_id pic32_uart_ids[] = { |
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{ .compatible = "microchip,pic32mzda-uart" }, |
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{} |
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}; |
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U_BOOT_DRIVER(pic32_serial) = { |
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.name = "pic32-uart", |
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.id = UCLASS_SERIAL, |
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.of_match = pic32_uart_ids, |
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.probe = pic32_uart_probe, |
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.ops = &pic32_uart_ops, |
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.flags = DM_FLAG_PRE_RELOC, |
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.priv_auto_alloc_size = sizeof(struct pic32_uart_priv), |
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}; |
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#ifdef CONFIG_DEBUG_UART_PIC32 |
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#include <debug_uart.h> |
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static inline void _debug_uart_init(void) |
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{ |
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void __iomem *base = (void __iomem *)CONFIG_DEBUG_UART_BASE; |
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pic32_serial_init(base, CONFIG_DEBUG_UART_CLOCK, CONFIG_BAUDRATE); |
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} |
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static inline void _debug_uart_putc(int ch) |
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{ |
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writel(ch, CONFIG_DEBUG_UART_BASE + U_TXR); |
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} |
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DEBUG_UART_FUNCS |
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#endif
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