diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_bcm7271.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_bcm7271.c | 1202 |
1 files changed, 1202 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_bcm7271.c b/drivers/tty/serial/8250/8250_bcm7271.c new file mode 100644 index 000000000000..725a450058f8 --- /dev/null +++ b/drivers/tty/serial/8250/8250_bcm7271.c @@ -0,0 +1,1202 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* Copyright (c) 2020, Broadcom */ +/* + * 8250-core based driver for Broadcom ns16550a UARTs + * + * This driver uses the standard 8250 driver core but adds additional + * optional features including the ability to use a baud rate clock + * mux for more accurate high speed baud rate selection and also + * an optional DMA engine. + * + */ + +#include <linux/module.h> +#include <linux/types.h> +#include <linux/tty.h> +#include <linux/errno.h> +#include <linux/device.h> +#include <linux/io.h> +#include <linux/of.h> +#include <linux/dma-mapping.h> +#include <linux/tty_flip.h> +#include <linux/delay.h> +#include <linux/clk.h> +#include <linux/debugfs.h> + +#include "8250.h" + +/* Register definitions for UART DMA block. Version 1.1 or later. */ +#define UDMA_ARB_RX 0x00 +#define UDMA_ARB_TX 0x04 +#define UDMA_ARB_REQ 0x00000001 +#define UDMA_ARB_GRANT 0x00000002 + +#define UDMA_RX_REVISION 0x00 +#define UDMA_RX_REVISION_REQUIRED 0x00000101 +#define UDMA_RX_CTRL 0x04 +#define UDMA_RX_CTRL_BUF_CLOSE_MODE 0x00010000 +#define UDMA_RX_CTRL_MASK_WR_DONE 0x00008000 +#define UDMA_RX_CTRL_ENDIAN_OVERRIDE 0x00004000 +#define UDMA_RX_CTRL_ENDIAN 0x00002000 +#define UDMA_RX_CTRL_OE_IS_ERR 0x00001000 +#define UDMA_RX_CTRL_PE_IS_ERR 0x00000800 +#define UDMA_RX_CTRL_FE_IS_ERR 0x00000400 +#define UDMA_RX_CTRL_NUM_BUF_USED_MASK 0x000003c0 +#define UDMA_RX_CTRL_NUM_BUF_USED_SHIFT 6 +#define UDMA_RX_CTRL_BUF_CLOSE_CLK_SEL_SYS 0x00000020 +#define UDMA_RX_CTRL_BUF_CLOSE_ENA 0x00000010 +#define UDMA_RX_CTRL_TIMEOUT_CLK_SEL_SYS 0x00000008 +#define UDMA_RX_CTRL_TIMEOUT_ENA 0x00000004 +#define UDMA_RX_CTRL_ABORT 0x00000002 +#define UDMA_RX_CTRL_ENA 0x00000001 +#define UDMA_RX_STATUS 0x08 +#define UDMA_RX_STATUS_ACTIVE_BUF_MASK 0x0000000f +#define UDMA_RX_TRANSFER_LEN 0x0c +#define UDMA_RX_TRANSFER_TOTAL 0x10 +#define UDMA_RX_BUFFER_SIZE 0x14 +#define UDMA_RX_SRC_ADDR 0x18 +#define UDMA_RX_TIMEOUT 0x1c +#define UDMA_RX_BUFFER_CLOSE 0x20 +#define UDMA_RX_BLOCKOUT_COUNTER 0x24 +#define UDMA_RX_BUF0_PTR_LO 0x28 +#define UDMA_RX_BUF0_PTR_HI 0x2c +#define UDMA_RX_BUF0_STATUS 0x30 +#define UDMA_RX_BUFX_STATUS_OVERRUN_ERR 0x00000010 +#define UDMA_RX_BUFX_STATUS_FRAME_ERR 0x00000008 +#define UDMA_RX_BUFX_STATUS_PARITY_ERR 0x00000004 +#define UDMA_RX_BUFX_STATUS_CLOSE_EXPIRED 0x00000002 +#define UDMA_RX_BUFX_STATUS_DATA_RDY 0x00000001 +#define UDMA_RX_BUF0_DATA_LEN 0x34 +#define UDMA_RX_BUF1_PTR_LO 0x38 +#define UDMA_RX_BUF1_PTR_HI 0x3c +#define UDMA_RX_BUF1_STATUS 0x40 +#define UDMA_RX_BUF1_DATA_LEN 0x44 + +#define UDMA_TX_REVISION 0x00 +#define UDMA_TX_REVISION_REQUIRED 0x00000101 +#define UDMA_TX_CTRL 0x04 +#define UDMA_TX_CTRL_ENDIAN_OVERRIDE 0x00000080 +#define UDMA_TX_CTRL_ENDIAN 0x00000040 +#define UDMA_TX_CTRL_NUM_BUF_USED_MASK 0x00000030 +#define UDMA_TX_CTRL_NUM_BUF_USED_1 0x00000010 +#define UDMA_TX_CTRL_ABORT 0x00000002 +#define UDMA_TX_CTRL_ENA 0x00000001 +#define UDMA_TX_DST_ADDR 0x08 +#define UDMA_TX_BLOCKOUT_COUNTER 0x10 +#define UDMA_TX_TRANSFER_LEN 0x14 +#define UDMA_TX_TRANSFER_TOTAL 0x18 +#define UDMA_TX_STATUS 0x20 +#define UDMA_TX_BUF0_PTR_LO 0x24 +#define UDMA_TX_BUF0_PTR_HI 0x28 +#define UDMA_TX_BUF0_STATUS 0x2c +#define UDMA_TX_BUFX_LAST 0x00000002 +#define UDMA_TX_BUFX_EMPTY 0x00000001 +#define UDMA_TX_BUF0_DATA_LEN 0x30 +#define UDMA_TX_BUF0_DATA_SENT 0x34 +#define UDMA_TX_BUF1_PTR_LO 0x38 + +#define UDMA_INTR_STATUS 0x00 +#define UDMA_INTR_ARB_TX_GRANT 0x00040000 +#define UDMA_INTR_ARB_RX_GRANT 0x00020000 +#define UDMA_INTR_TX_ALL_EMPTY 0x00010000 +#define UDMA_INTR_TX_EMPTY_BUF1 0x00008000 +#define UDMA_INTR_TX_EMPTY_BUF0 0x00004000 +#define UDMA_INTR_TX_ABORT 0x00002000 +#define UDMA_INTR_TX_DONE 0x00001000 +#define UDMA_INTR_RX_ERROR 0x00000800 +#define UDMA_INTR_RX_TIMEOUT 0x00000400 +#define UDMA_INTR_RX_READY_BUF7 0x00000200 +#define UDMA_INTR_RX_READY_BUF6 0x00000100 +#define UDMA_INTR_RX_READY_BUF5 0x00000080 +#define UDMA_INTR_RX_READY_BUF4 0x00000040 +#define UDMA_INTR_RX_READY_BUF3 0x00000020 +#define UDMA_INTR_RX_READY_BUF2 0x00000010 +#define UDMA_INTR_RX_READY_BUF1 0x00000008 +#define UDMA_INTR_RX_READY_BUF0 0x00000004 +#define UDMA_INTR_RX_READY_MASK 0x000003fc +#define UDMA_INTR_RX_READY_SHIFT 2 +#define UDMA_INTR_RX_ABORT 0x00000002 +#define UDMA_INTR_RX_DONE 0x00000001 +#define UDMA_INTR_SET 0x04 +#define UDMA_INTR_CLEAR 0x08 +#define UDMA_INTR_MASK_STATUS 0x0c +#define UDMA_INTR_MASK_SET 0x10 +#define UDMA_INTR_MASK_CLEAR 0x14 + + +#define UDMA_RX_INTERRUPTS ( \ + UDMA_INTR_RX_ERROR | \ + UDMA_INTR_RX_TIMEOUT | \ + UDMA_INTR_RX_READY_BUF0 | \ + UDMA_INTR_RX_READY_BUF1 | \ + UDMA_INTR_RX_READY_BUF2 | \ + UDMA_INTR_RX_READY_BUF3 | \ + UDMA_INTR_RX_READY_BUF4 | \ + UDMA_INTR_RX_READY_BUF5 | \ + UDMA_INTR_RX_READY_BUF6 | \ + UDMA_INTR_RX_READY_BUF7 | \ + UDMA_INTR_RX_ABORT | \ + UDMA_INTR_RX_DONE) + +#define UDMA_RX_ERR_INTERRUPTS ( \ + UDMA_INTR_RX_ERROR | \ + UDMA_INTR_RX_TIMEOUT | \ + UDMA_INTR_RX_ABORT | \ + UDMA_INTR_RX_DONE) + +#define UDMA_TX_INTERRUPTS ( \ + UDMA_INTR_TX_ABORT | \ + UDMA_INTR_TX_DONE) + +#define UDMA_IS_RX_INTERRUPT(status) ((status) & UDMA_RX_INTERRUPTS) +#define UDMA_IS_TX_INTERRUPT(status) ((status) & UDMA_TX_INTERRUPTS) + + +/* Current devices have 8 sets of RX buffer registers */ +#define UDMA_RX_BUFS_COUNT 8 +#define UDMA_RX_BUFS_REG_OFFSET (UDMA_RX_BUF1_PTR_LO - UDMA_RX_BUF0_PTR_LO) +#define UDMA_RX_BUFx_PTR_LO(x) (UDMA_RX_BUF0_PTR_LO + \ + ((x) * UDMA_RX_BUFS_REG_OFFSET)) +#define UDMA_RX_BUFx_PTR_HI(x) (UDMA_RX_BUF0_PTR_HI + \ + ((x) * UDMA_RX_BUFS_REG_OFFSET)) +#define UDMA_RX_BUFx_STATUS(x) (UDMA_RX_BUF0_STATUS + \ + ((x) * UDMA_RX_BUFS_REG_OFFSET)) +#define UDMA_RX_BUFx_DATA_LEN(x) (UDMA_RX_BUF0_DATA_LEN + \ + ((x) * UDMA_RX_BUFS_REG_OFFSET)) + +/* Current devices have 2 sets of TX buffer registers */ +#define UDMA_TX_BUFS_COUNT 2 +#define UDMA_TX_BUFS_REG_OFFSET (UDMA_TX_BUF1_PTR_LO - UDMA_TX_BUF0_PTR_LO) +#define UDMA_TX_BUFx_PTR_LO(x) (UDMA_TX_BUF0_PTR_LO + \ + ((x) * UDMA_TX_BUFS_REG_OFFSET)) +#define UDMA_TX_BUFx_PTR_HI(x) (UDMA_TX_BUF0_PTR_HI + \ + ((x) * UDMA_TX_BUFS_REG_OFFSET)) +#define UDMA_TX_BUFx_STATUS(x) (UDMA_TX_BUF0_STATUS + \ + ((x) * UDMA_TX_BUFS_REG_OFFSET)) +#define UDMA_TX_BUFx_DATA_LEN(x) (UDMA_TX_BUF0_DATA_LEN + \ + ((x) * UDMA_TX_BUFS_REG_OFFSET)) +#define UDMA_TX_BUFx_DATA_SENT(x) (UDMA_TX_BUF0_DATA_SENT + \ + ((x) * UDMA_TX_BUFS_REG_OFFSET)) +#define REGS_8250 0 +#define REGS_DMA_RX 1 +#define REGS_DMA_TX 2 +#define REGS_DMA_ISR 3 +#define REGS_DMA_ARB 4 +#define REGS_MAX 5 + +#define TX_BUF_SIZE 4096 +#define RX_BUF_SIZE 4096 +#define RX_BUFS_COUNT 2 +#define KHZ 1000 +#define MHZ(x) ((x) * KHZ * KHZ) + +static const u32 brcmstb_rate_table[] = { + MHZ(81), + MHZ(108), + MHZ(64), /* Actually 64285715 for some chips */ + MHZ(48), +}; + +static const u32 brcmstb_rate_table_7278[] = { + MHZ(81), + MHZ(108), + 0, + MHZ(48), +}; + +struct brcmuart_priv { + int line; + struct clk *baud_mux_clk; + unsigned long default_mux_rate; + u32 real_rates[ARRAY_SIZE(brcmstb_rate_table)]; + const u32 *rate_table; + ktime_t char_wait; + struct uart_port *up; + struct hrtimer hrt; + bool shutdown; + bool dma_enabled; + struct uart_8250_dma dma; + void __iomem *regs[REGS_MAX]; + dma_addr_t rx_addr; + void *rx_bufs; + size_t rx_size; + int rx_next_buf; + dma_addr_t tx_addr; + void *tx_buf; + size_t tx_size; + bool tx_running; + bool rx_running; + struct dentry *debugfs_dir; + + /* stats exposed through debugfs */ + u64 dma_rx_partial_buf; + u64 dma_rx_full_buf; + u32 rx_bad_timeout_late_char; + u32 rx_bad_timeout_no_char; + u32 rx_missing_close_timeout; + u32 rx_err; + u32 rx_timeout; + u32 rx_abort; +}; + +static struct dentry *brcmuart_debugfs_root; + +/* + * Register access routines + */ +static u32 udma_readl(struct brcmuart_priv *priv, + int reg_type, int offset) +{ + return readl(priv->regs[reg_type] + offset); +} + +static void udma_writel(struct brcmuart_priv *priv, + int reg_type, int offset, u32 value) +{ + writel(value, priv->regs[reg_type] + offset); +} + +static void udma_set(struct brcmuart_priv *priv, + int reg_type, int offset, u32 bits) +{ + void __iomem *reg = priv->regs[reg_type] + offset; + u32 value; + + value = readl(reg); + value |= bits; + writel(value, reg); +} + +static void udma_unset(struct brcmuart_priv *priv, + int reg_type, int offset, u32 bits) +{ + void __iomem *reg = priv->regs[reg_type] + offset; + u32 value; + + value = readl(reg); + value &= ~bits; + writel(value, reg); +} + +/* + * The UART DMA engine hardware can be used by multiple UARTS, but + * only one at a time. Sharing is not currently supported so + * the first UART to request the DMA engine will get it and any + * subsequent requests by other UARTS will fail. + */ +static int brcmuart_arbitration(struct brcmuart_priv *priv, bool acquire) +{ + u32 rx_grant; + u32 tx_grant; + int waits; + int ret = 0; + + if (acquire) { + udma_set(priv, REGS_DMA_ARB, UDMA_ARB_RX, UDMA_ARB_REQ); + udma_set(priv, REGS_DMA_ARB, UDMA_ARB_TX, UDMA_ARB_REQ); + + waits = 1; + while (1) { + rx_grant = udma_readl(priv, REGS_DMA_ARB, UDMA_ARB_RX); + tx_grant = udma_readl(priv, REGS_DMA_ARB, UDMA_ARB_TX); + if (rx_grant & tx_grant & UDMA_ARB_GRANT) + return 0; + if (waits-- == 0) + break; + msleep(1); + } + ret = 1; + } + + udma_unset(priv, REGS_DMA_ARB, UDMA_ARB_RX, UDMA_ARB_REQ); + udma_unset(priv, REGS_DMA_ARB, UDMA_ARB_TX, UDMA_ARB_REQ); + return ret; +} + +static void brcmuart_init_dma_hardware(struct brcmuart_priv *priv) +{ + u32 daddr; + u32 value; + int x; + + /* Start with all interrupts disabled */ + udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_SET, 0xffffffff); + + udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFFER_SIZE, RX_BUF_SIZE); + + /* + * Setup buffer close to happen when 32 character times have + * elapsed since the last character was received. + */ + udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFFER_CLOSE, 16*10*32); + value = (RX_BUFS_COUNT << UDMA_RX_CTRL_NUM_BUF_USED_SHIFT) + | UDMA_RX_CTRL_BUF_CLOSE_MODE + | UDMA_RX_CTRL_BUF_CLOSE_ENA; + udma_writel(priv, REGS_DMA_RX, UDMA_RX_CTRL, value); + + udma_writel(priv, REGS_DMA_RX, UDMA_RX_BLOCKOUT_COUNTER, 0); + daddr = priv->rx_addr; + for (x = 0; x < RX_BUFS_COUNT; x++) { + + /* Set RX transfer length to 0 for unknown */ + udma_writel(priv, REGS_DMA_RX, UDMA_RX_TRANSFER_LEN, 0); + + udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFx_PTR_LO(x), + lower_32_bits(daddr)); + udma_writel(priv, REGS_DMA_RX, UDMA_RX_BUFx_PTR_HI(x), + upper_32_bits(daddr)); + daddr += RX_BUF_SIZE; + } + + daddr = priv->tx_addr; + udma_writel(priv, REGS_DMA_TX, UDMA_TX_BUFx_PTR_LO(0), + lower_32_bits(daddr)); + udma_writel(priv, REGS_DMA_TX, UDMA_TX_BUFx_PTR_HI(0), + upper_32_bits(daddr)); + udma_writel(priv, REGS_DMA_TX, UDMA_TX_CTRL, + UDMA_TX_CTRL_NUM_BUF_USED_1); + + /* clear all interrupts then enable them */ + udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_CLEAR, 0xffffffff); + udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_CLEAR, + UDMA_RX_INTERRUPTS | UDMA_TX_INTERRUPTS); + +} + +static void start_rx_dma(struct uart_8250_port *p) +{ + struct brcmuart_priv *priv = p->port.private_data; + int x; + + udma_unset(priv, REGS_DMA_RX, UDMA_RX_CTRL, UDMA_RX_CTRL_ENA); + + /* Clear the RX ready bit for all buffers */ + for (x = 0; x < RX_BUFS_COUNT; x++) + udma_unset(priv, REGS_DMA_RX, UDMA_RX_BUFx_STATUS(x), + UDMA_RX_BUFX_STATUS_DATA_RDY); + + /* always start with buffer 0 */ + udma_unset(priv, REGS_DMA_RX, UDMA_RX_STATUS, + UDMA_RX_STATUS_ACTIVE_BUF_MASK); + priv->rx_next_buf = 0; + + udma_set(priv, REGS_DMA_RX, UDMA_RX_CTRL, UDMA_RX_CTRL_ENA); + priv->rx_running = true; +} + +static void stop_rx_dma(struct uart_8250_port *p) +{ + struct brcmuart_priv *priv = p->port.private_data; + + /* If RX is running, set the RX ABORT */ + if (priv->rx_running) + udma_set(priv, REGS_DMA_RX, UDMA_RX_CTRL, UDMA_RX_CTRL_ABORT); +} + +static int stop_tx_dma(struct uart_8250_port *p) +{ + struct brcmuart_priv *priv = p->port.private_data; + u32 value; + + /* If TX is running, set the TX ABORT */ + value = udma_readl(priv, REGS_DMA_TX, UDMA_TX_CTRL); + if (value & UDMA_TX_CTRL_ENA) + udma_set(priv, REGS_DMA_TX, UDMA_TX_CTRL, UDMA_TX_CTRL_ABORT); + priv->tx_running = false; + return 0; +} + +/* + * NOTE: printk's in this routine will hang the system if this is + * the console tty + */ +static int brcmuart_tx_dma(struct uart_8250_port *p) +{ + struct brcmuart_priv *priv = p->port.private_data; + struct circ_buf *xmit = &p->port.state->xmit; + u32 tx_size; + + if (uart_tx_stopped(&p->port) || priv->tx_running || + uart_circ_empty(xmit)) { + return 0; + } + tx_size = CIRC_CNT_TO_END(xmit->head, xmit->tail, UART_XMIT_SIZE); + + priv->dma.tx_err = 0; + memcpy(priv->tx_buf, &xmit->buf[xmit->tail], tx_size); + xmit->tail += tx_size; + xmit->tail &= UART_XMIT_SIZE - 1; + p->port.icount.tx += tx_size; + + if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS) + uart_write_wakeup(&p->port); + + udma_writel(priv, REGS_DMA_TX, UDMA_TX_TRANSFER_LEN, tx_size); + udma_writel(priv, REGS_DMA_TX, UDMA_TX_BUF0_DATA_LEN, tx_size); + udma_unset(priv, REGS_DMA_TX, UDMA_TX_BUF0_STATUS, UDMA_TX_BUFX_EMPTY); + udma_set(priv, REGS_DMA_TX, UDMA_TX_CTRL, UDMA_TX_CTRL_ENA); + priv->tx_running = true; + + return 0; +} + +static void brcmuart_rx_buf_done_isr(struct uart_port *up, int index) +{ + struct brcmuart_priv *priv = up->private_data; + struct tty_port *tty_port = &up->state->port; + u32 status; + u32 length; + u32 copied; + + /* Make sure we're still in sync with the hardware */ + status = udma_readl(priv, REGS_DMA_RX, UDMA_RX_BUFx_STATUS(index)); + length = udma_readl(priv, REGS_DMA_RX, UDMA_RX_BUFx_DATA_LEN(index)); + + if ((status & UDMA_RX_BUFX_STATUS_DATA_RDY) == 0) { + dev_err(up->dev, "RX done interrupt but DATA_RDY not found\n"); + return; + } + if (status & (UDMA_RX_BUFX_STATUS_OVERRUN_ERR | + UDMA_RX_BUFX_STATUS_FRAME_ERR | + UDMA_RX_BUFX_STATUS_PARITY_ERR)) { + if (status & UDMA_RX_BUFX_STATUS_OVERRUN_ERR) { + up->icount.overrun++; + dev_warn(up->dev, "RX OVERRUN Error\n"); + } + if (status & UDMA_RX_BUFX_STATUS_FRAME_ERR) { + up->icount.frame++; + dev_warn(up->dev, "RX FRAMING Error\n"); + } + if (status & UDMA_RX_BUFX_STATUS_PARITY_ERR) { + up->icount.parity++; + dev_warn(up->dev, "RX PARITY Error\n"); + } + } + copied = (u32)tty_insert_flip_string( + tty_port, + priv->rx_bufs + (index * RX_BUF_SIZE), + length); + if (copied != length) { + dev_warn(up->dev, "Flip buffer overrun of %d bytes\n", + length - copied); + up->icount.overrun += length - copied; + } + up->icount.rx += length; + if (status & UDMA_RX_BUFX_STATUS_CLOSE_EXPIRED) + priv->dma_rx_partial_buf++; + else if (length != RX_BUF_SIZE) + /* + * This is a bug in the controller that doesn't cause + * any problems but will be fixed in the future. + */ + priv->rx_missing_close_timeout++; + else + priv->dma_rx_full_buf++; + + tty_flip_buffer_push(tty_port); +} + +static void brcmuart_rx_isr(struct uart_port *up, u32 rx_isr) +{ + struct brcmuart_priv *priv = up->private_data; + struct device *dev = up->dev; + u32 rx_done_isr; + u32 check_isr; + + rx_done_isr = (rx_isr & UDMA_INTR_RX_READY_MASK); + while (rx_done_isr) { + check_isr = UDMA_INTR_RX_READY_BUF0 << priv->rx_next_buf; + if (check_isr & rx_done_isr) { + brcmuart_rx_buf_done_isr(up, priv->rx_next_buf); + } else { + dev_err(dev, + "RX buffer ready out of sequence, restarting RX DMA\n"); + start_rx_dma(up_to_u8250p(up)); + break; + } + if (rx_isr & UDMA_RX_ERR_INTERRUPTS) { + if (rx_isr & UDMA_INTR_RX_ERROR) + priv->rx_err++; + if (rx_isr & UDMA_INTR_RX_TIMEOUT) { + priv->rx_timeout++; + dev_err(dev, "RX TIMEOUT Error\n"); + } + if (rx_isr & UDMA_INTR_RX_ABORT) + priv->rx_abort++; + priv->rx_running = false; + } + /* If not ABORT, re-enable RX buffer */ + if (!(rx_isr & UDMA_INTR_RX_ABORT)) + udma_unset(priv, REGS_DMA_RX, + UDMA_RX_BUFx_STATUS(priv->rx_next_buf), + UDMA_RX_BUFX_STATUS_DATA_RDY); + rx_done_isr &= ~check_isr; + priv->rx_next_buf++; + if (priv->rx_next_buf == RX_BUFS_COUNT) + priv->rx_next_buf = 0; + } +} + +static void brcmuart_tx_isr(struct uart_port *up, u32 isr) +{ + struct brcmuart_priv *priv = up->private_data; + struct device *dev = up->dev; + struct uart_8250_port *port_8250 = up_to_u8250p(up); + struct circ_buf *xmit = &port_8250->port.state->xmit; + + if (isr & UDMA_INTR_TX_ABORT) { + if (priv->tx_running) + dev_err(dev, "Unexpected TX_ABORT interrupt\n"); + return; + } + priv->tx_running = false; + if (!uart_circ_empty(xmit) && !uart_tx_stopped(up)) + brcmuart_tx_dma(port_8250); +} + +static irqreturn_t brcmuart_isr(int irq, void *dev_id) +{ + struct uart_port *up = dev_id; + struct device *dev = up->dev; + struct brcmuart_priv *priv = up->private_data; + unsigned long flags; + u32 interrupts; + u32 rval; + u32 tval; + + interrupts = udma_readl(priv, REGS_DMA_ISR, UDMA_INTR_STATUS); + if (interrupts == 0) + return IRQ_NONE; + + spin_lock_irqsave(&up->lock, flags); + + /* Clear all interrupts */ + udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_CLEAR, interrupts); + + rval = UDMA_IS_RX_INTERRUPT(interrupts); + if (rval) + brcmuart_rx_isr(up, rval); + tval = UDMA_IS_TX_INTERRUPT(interrupts); + if (tval) + brcmuart_tx_isr(up, tval); + if ((rval | tval) == 0) + dev_warn(dev, "Spurious interrupt: 0x%x\n", interrupts); + + spin_unlock_irqrestore(&up->lock, flags); + return IRQ_HANDLED; +} + +static int brcmuart_startup(struct uart_port *port) +{ + int res; + struct uart_8250_port *up = up_to_u8250p(port); + struct brcmuart_priv *priv = up->port.private_data; + + priv->shutdown = false; + + /* + * prevent serial8250_do_startup() from allocating non-existent + * DMA resources + */ + up->dma = NULL; + + res = serial8250_do_startup(port); + if (!priv->dma_enabled) + return res; + /* + * Disable the Receive Data Interrupt because the DMA engine + * will handle this. + */ + up->ier &= ~UART_IER_RDI; + serial_port_out(port, UART_IER, up->ier); + + priv->tx_running = false; + priv->dma.rx_dma = NULL; + priv->dma.tx_dma = brcmuart_tx_dma; + up->dma = &priv->dma; + + brcmuart_init_dma_hardware(priv); + start_rx_dma(up); + return res; +} + +static void brcmuart_shutdown(struct uart_port *port) +{ + struct uart_8250_port *up = up_to_u8250p(port); + struct brcmuart_priv *priv = up->port.private_data; + unsigned long flags; + + spin_lock_irqsave(&port->lock, flags); + priv->shutdown = true; + if (priv->dma_enabled) { + stop_rx_dma(up); + stop_tx_dma(up); + /* disable all interrupts */ + udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_SET, + UDMA_RX_INTERRUPTS | UDMA_TX_INTERRUPTS); + } + + /* + * prevent serial8250_do_shutdown() from trying to free + * DMA resources that we never alloc'd for this driver. + */ + up->dma = NULL; + + spin_unlock_irqrestore(&port->lock, flags); + serial8250_do_shutdown(port); +} + +/* + * Not all clocks run at the exact specified rate, so set each requested + * rate and then get the actual rate. + */ +static void init_real_clk_rates(struct device *dev, struct brcmuart_priv *priv) +{ + int x; + int rc; + + priv->default_mux_rate = clk_get_rate(priv->baud_mux_clk); + for (x = 0; x < ARRAY_SIZE(priv->real_rates); x++) { + if (priv->rate_table[x] == 0) { + priv->real_rates[x] = 0; + continue; + } + rc = clk_set_rate(priv->baud_mux_clk, priv->rate_table[x]); + if (rc) { + dev_err(dev, "Error selecting BAUD MUX clock for %u\n", + priv->rate_table[x]); + priv->real_rates[x] = priv->rate_table[x]; + } else { + priv->real_rates[x] = clk_get_rate(priv->baud_mux_clk); + } + } + clk_set_rate(priv->baud_mux_clk, priv->default_mux_rate); +} + +static void set_clock_mux(struct uart_port *up, struct brcmuart_priv *priv, + u32 baud) +{ + u32 percent; + u32 best_percent = UINT_MAX; + u32 quot; + u32 best_quot = 1; + u32 rate; + int best_index = -1; + u64 hires_rate; + u64 hires_baud; + u64 hires_err; + int rc; + int i; + int real_baud; + + /* If the Baud Mux Clock was not specified, just return */ + if (priv->baud_mux_clk == NULL) + return; + + /* Find the closest match for specified baud */ + for (i = 0; i < ARRAY_SIZE(priv->real_rates); i++) { + if (priv->real_rates[i] == 0) + continue; + rate = priv->real_rates[i] / 16; + quot = DIV_ROUND_CLOSEST(rate, baud); + if (!quot) + continue; + + /* increase resolution to get xx.xx percent */ + hires_rate = (u64)rate * 10000; + hires_baud = (u64)baud * 10000; + + hires_err = div_u64(hires_rate, (u64)quot); + + /* get the delta */ + if (hires_err > hires_baud) + hires_err = (hires_err - hires_baud); + else + hires_err = (hires_baud - hires_err); + + percent = (unsigned long)DIV_ROUND_CLOSEST_ULL(hires_err, baud); + dev_dbg(up->dev, + "Baud rate: %u, MUX Clk: %u, Error: %u.%u%%\n", + baud, priv->real_rates[i], percent / 100, + percent % 100); + if (percent < best_percent) { + best_percent = percent; + best_index = i; + best_quot = quot; + } + } + if (best_index == -1) { + dev_err(up->dev, "Error, %d BAUD rate is too fast.\n", baud); + return; + } + rate = priv->real_rates[best_index]; + rc = clk_set_rate(priv->baud_mux_clk, rate); + if (rc) + dev_err(up->dev, "Error selecting BAUD MUX clock\n"); + + /* Error over 3 percent will cause data errors */ + if (best_percent > 300) + dev_err(up->dev, "Error, baud: %d has %u.%u%% error\n", + baud, percent / 100, percent % 100); + + real_baud = rate / 16 / best_quot; + dev_dbg(up->dev, "Selecting BAUD MUX rate: %u\n", rate); + dev_dbg(up->dev, "Requested baud: %u, Actual baud: %u\n", + baud, real_baud); + + /* calc nanoseconds for 1.5 characters time at the given baud rate */ + i = NSEC_PER_SEC / real_baud / 10; + i += (i / 2); + priv->char_wait = ns_to_ktime(i); + + up->uartclk = rate; +} + +static void brcmstb_set_termios(struct uart_port *up, + struct ktermios *termios, + struct ktermios *old) +{ + struct uart_8250_port *p8250 = up_to_u8250p(up); + struct brcmuart_priv *priv = up->private_data; + + if (priv->dma_enabled) + stop_rx_dma(p8250); + set_clock_mux(up, priv, tty_termios_baud_rate(termios)); + serial8250_do_set_termios(up, termios, old); + if (p8250->mcr & UART_MCR_AFE) + p8250->port.status |= UPSTAT_AUTOCTS; + if (priv->dma_enabled) + start_rx_dma(p8250); +} + +static int brcmuart_handle_irq(struct uart_port *p) +{ + unsigned int iir = serial_port_in(p, UART_IIR); + struct brcmuart_priv *priv = p->private_data; + struct uart_8250_port *up = up_to_u8250p(p); + unsigned int status; + unsigned long flags; + unsigned int ier; + unsigned int mcr; + int handled = 0; + + /* + * There's a bug in some 8250 cores where we get a timeout + * interrupt but there is no data ready. + */ + if (((iir & UART_IIR_ID) == UART_IIR_RX_TIMEOUT) && !(priv->shutdown)) { + spin_lock_irqsave(&p->lock, flags); + status = serial_port_in(p, UART_LSR); + if ((status & UART_LSR_DR) == 0) { + + ier = serial_port_in(p, UART_IER); + /* + * if Receive Data Interrupt is enabled and + * we're uing hardware flow control, deassert + * RTS and wait for any chars in the pipline to + * arrive and then check for DR again. + */ + if ((ier & UART_IER_RDI) && (up->mcr & UART_MCR_AFE)) { + ier &= ~(UART_IER_RLSI | UART_IER_RDI); + serial_port_out(p, UART_IER, ier); + mcr = serial_port_in(p, UART_MCR); + mcr &= ~UART_MCR_RTS; + serial_port_out(p, UART_MCR, mcr); + hrtimer_start(&priv->hrt, priv->char_wait, + HRTIMER_MODE_REL); + } else { + serial_port_in(p, UART_RX); + } + + handled = 1; + } + spin_unlock_irqrestore(&p->lock, flags); + if (handled) + return 1; + } + return serial8250_handle_irq(p, iir); +} + +static enum hrtimer_restart brcmuart_hrtimer_func(struct hrtimer *t) +{ + struct brcmuart_priv *priv = container_of(t, struct brcmuart_priv, hrt); + struct uart_port *p = priv->up; + struct uart_8250_port *up = up_to_u8250p(p); + unsigned int status; + unsigned long flags; + + if (priv->shutdown) + return HRTIMER_NORESTART; + + spin_lock_irqsave(&p->lock, flags); + status = serial_port_in(p, UART_LSR); + + /* + * If a character did not arrive after the timeout, clear the false + * receive timeout. + */ + if ((status & UART_LSR_DR) == 0) { + serial_port_in(p, UART_RX); + priv->rx_bad_timeout_no_char++; + } else { + priv->rx_bad_timeout_late_char++; + } + + /* re-enable receive unless upper layer has disabled it */ + if ((up->ier & (UART_IER_RLSI | UART_IER_RDI)) == + (UART_IER_RLSI | UART_IER_RDI)) { + status = serial_port_in(p, UART_IER); + status |= (UART_IER_RLSI | UART_IER_RDI); + serial_port_out(p, UART_IER, status); + status = serial_port_in(p, UART_MCR); + status |= UART_MCR_RTS; + serial_port_out(p, UART_MCR, status); + } + spin_unlock_irqrestore(&p->lock, flags); + return HRTIMER_NORESTART; +} + +static const struct of_device_id brcmuart_dt_ids[] = { + { + .compatible = "brcm,bcm7278-uart", + .data = brcmstb_rate_table_7278, + }, + { + .compatible = "brcm,bcm7271-uart", + .data = brcmstb_rate_table, + }, + {}, +}; + +MODULE_DEVICE_TABLE(of, brcmuart_dt_ids); + +static void brcmuart_free_bufs(struct device *dev, struct brcmuart_priv *priv) +{ + if (priv->rx_bufs) + dma_free_coherent(dev, priv->rx_size, priv->rx_bufs, + priv->rx_addr); + if (priv->tx_buf) + dma_free_coherent(dev, priv->tx_size, priv->tx_buf, + priv->tx_addr); +} + +static void brcmuart_throttle(struct uart_port *port) +{ + struct brcmuart_priv *priv = port->private_data; + + udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_SET, UDMA_RX_INTERRUPTS); +} + +static void brcmuart_unthrottle(struct uart_port *port) +{ + struct brcmuart_priv *priv = port->private_data; + + udma_writel(priv, REGS_DMA_ISR, UDMA_INTR_MASK_CLEAR, + UDMA_RX_INTERRUPTS); +} + +static int debugfs_stats_show(struct seq_file *s, void *unused) +{ + struct brcmuart_priv *priv = s->private; + + seq_printf(s, "rx_err:\t\t\t\t%u\n", + priv->rx_err); + seq_printf(s, "rx_timeout:\t\t\t%u\n", + priv->rx_timeout); + seq_printf(s, "rx_abort:\t\t\t%u\n", + priv->rx_abort); + seq_printf(s, "rx_bad_timeout_late_char:\t%u\n", + priv->rx_bad_timeout_late_char); + seq_printf(s, "rx_bad_timeout_no_char:\t\t%u\n", + priv->rx_bad_timeout_no_char); + seq_printf(s, "rx_missing_close_timeout:\t%u\n", + priv->rx_missing_close_timeout); + if (priv->dma_enabled) { + seq_printf(s, "dma_rx_partial_buf:\t\t%llu\n", + priv->dma_rx_partial_buf); + seq_printf(s, "dma_rx_full_buf:\t\t%llu\n", + priv->dma_rx_full_buf); + } + return 0; +} +DEFINE_SHOW_ATTRIBUTE(debugfs_stats); + +static void brcmuart_init_debugfs(struct brcmuart_priv *priv, + const char *device) +{ + priv->debugfs_dir = debugfs_create_dir(device, brcmuart_debugfs_root); + debugfs_create_file("stats", 0444, priv->debugfs_dir, priv, + &debugfs_stats_fops); +} + + +static int brcmuart_probe(struct platform_device *pdev) +{ + struct resource *regs; + struct device_node *np = pdev->dev.of_node; + const struct of_device_id *of_id = NULL; + struct uart_8250_port *new_port; + struct device *dev = &pdev->dev; + struct brcmuart_priv *priv; + struct clk *baud_mux_clk; + struct uart_8250_port up; + struct resource *irq; + void __iomem *membase = 0; + resource_size_t mapbase = 0; + u32 clk_rate = 0; + int ret; + int x; + int dma_irq; + static const char * const reg_names[REGS_MAX] = { + "uart", "dma_rx", "dma_tx", "dma_intr2", "dma_arb" + }; + + irq = platform_get_resource(pdev, IORESOURCE_IRQ, 0); + if (!irq) { + dev_err(dev, "missing irq\n"); + return -EINVAL; + } + priv = devm_kzalloc(dev, sizeof(struct brcmuart_priv), + GFP_KERNEL); + if (!priv) + return -ENOMEM; + + of_id = of_match_node(brcmuart_dt_ids, np); + if (!of_id || !of_id->data) + priv->rate_table = brcmstb_rate_table; + else + priv->rate_table = of_id->data; + + for (x = 0; x < REGS_MAX; x++) { + regs = platform_get_resource_byname(pdev, IORESOURCE_MEM, + reg_names[x]); + if (!regs) + break; + priv->regs[x] = devm_ioremap(dev, regs->start, + resource_size(regs)); + if (!priv->regs[x]) + return -ENOMEM; + if (x == REGS_8250) { + mapbase = regs->start; + membase = priv->regs[x]; + } + } + + /* We should have just the uart base registers or all the registers */ + if (x != 1 && x != REGS_MAX) { + dev_warn(dev, "%s registers not specified\n", reg_names[x]); + return -EINVAL; + } + + /* if the DMA registers were specified, try to enable DMA */ + if (x > REGS_DMA_RX) { + if (brcmuart_arbitration(priv, 1) == 0) { + u32 txrev = 0; + u32 rxrev = 0; + + txrev = udma_readl(priv, REGS_DMA_RX, UDMA_RX_REVISION); + rxrev = udma_readl(priv, REGS_DMA_TX, UDMA_TX_REVISION); + if ((txrev >= UDMA_TX_REVISION_REQUIRED) && + (rxrev >= UDMA_RX_REVISION_REQUIRED)) { + + /* Enable the use of the DMA hardware */ + priv->dma_enabled = true; + } else { + brcmuart_arbitration(priv, 0); + dev_err(dev, + "Unsupported DMA Hardware Revision\n"); + } + } else { + dev_err(dev, + "Timeout arbitrating for UART DMA hardware\n"); + } + } + + of_property_read_u32(np, "clock-frequency", &clk_rate); + + /* See if a Baud clock has been specified */ + baud_mux_clk = of_clk_get_by_name(np, "sw_baud"); + if (IS_ERR(baud_mux_clk)) { + if (PTR_ERR(baud_mux_clk) == -EPROBE_DEFER) + return -EPROBE_DEFER; + dev_dbg(dev, "BAUD MUX clock not specified\n"); + } else { + dev_dbg(dev, "BAUD MUX clock found\n"); + ret = clk_prepare_enable(baud_mux_clk); + if (ret) + return ret; + priv->baud_mux_clk = baud_mux_clk; + init_real_clk_rates(dev, priv); + clk_rate = priv->default_mux_rate; + } + + if (clk_rate == 0) { + dev_err(dev, "clock-frequency or clk not defined\n"); + return -EINVAL; + } + + dev_dbg(dev, "DMA is %senabled\n", priv->dma_enabled ? "" : "not "); + + memset(&up, 0, sizeof(up)); + up.port.type = PORT_16550A; + up.port.uartclk = clk_rate; + up.port.dev = dev; + up.port.mapbase = mapbase; + up.port.membase = membase; + up.port.irq = irq->start; + up.port.handle_irq = brcmuart_handle_irq; + up.port.regshift = 2; + up.port.iotype = of_device_is_big_endian(np) ? + UPIO_MEM32BE : UPIO_MEM32; + up.port.flags = UPF_SHARE_IRQ | UPF_BOOT_AUTOCONF + | UPF_FIXED_PORT | UPF_FIXED_TYPE; + up.port.dev = dev; + up.port.private_data = priv; + up.capabilities = UART_CAP_FIFO | UART_CAP_AFE; + up.port.fifosize = 32; + + /* Check for a fixed line number */ + ret = of_alias_get_id(np, "serial"); + if (ret >= 0) + up.port.line = ret; + + /* setup HR timer */ + hrtimer_init(&priv->hrt, CLOCK_MONOTONIC, HRTIMER_MODE_ABS); + priv->hrt.function = brcmuart_hrtimer_func; + + up.port.shutdown = brcmuart_shutdown; + up.port.startup = brcmuart_startup; + up.port.throttle = brcmuart_throttle; + up.port.unthrottle = brcmuart_unthrottle; + up.port.set_termios = brcmstb_set_termios; + + if (priv->dma_enabled) { + priv->rx_size = RX_BUF_SIZE * RX_BUFS_COUNT; + priv->rx_bufs = dma_alloc_coherent(dev, + priv->rx_size, + &priv->rx_addr, GFP_KERNEL); + if (!priv->rx_bufs) + goto err; + priv->tx_size = UART_XMIT_SIZE; + priv->tx_buf = dma_alloc_coherent(dev, + priv->tx_size, + &priv->tx_addr, GFP_KERNEL); + if (!priv->tx_buf) + goto err; + } + + ret = serial8250_register_8250_port(&up); + if (ret < 0) { + dev_err(dev, "unable to register 8250 port\n"); + goto err; + } + priv->line = ret; + new_port = serial8250_get_port(ret); + priv->up = &new_port->port; + if (priv->dma_enabled) { + dma_irq = platform_get_irq_byname(pdev, "dma"); + if (dma_irq < 0) { + dev_err(dev, "no IRQ resource info\n"); + goto err1; + } + ret = devm_request_irq(dev, dma_irq, brcmuart_isr, + IRQF_SHARED, "uart DMA irq", &new_port->port); + if (ret) { + dev_err(dev, "unable to register IRQ handler\n"); + goto err1; + } + } + platform_set_drvdata(pdev, priv); + brcmuart_init_debugfs(priv, dev_name(&pdev->dev)); + return 0; + +err1: + serial8250_unregister_port(priv->line); +err: + brcmuart_free_bufs(dev, priv); + brcmuart_arbitration(priv, 0); + return -ENODEV; +} + +static int brcmuart_remove(struct platform_device *pdev) +{ + struct brcmuart_priv *priv = platform_get_drvdata(pdev); + + debugfs_remove_recursive(priv->debugfs_dir); + hrtimer_cancel(&priv->hrt); + serial8250_unregister_port(priv->line); + brcmuart_free_bufs(&pdev->dev, priv); + brcmuart_arbitration(priv, 0); + return 0; +} + +static int __maybe_unused brcmuart_suspend(struct device *dev) +{ + struct brcmuart_priv *priv = dev_get_drvdata(dev); + + serial8250_suspend_port(priv->line); + clk_disable_unprepare(priv->baud_mux_clk); + + return 0; +} + +static int __maybe_unused brcmuart_resume(struct device *dev) +{ + struct brcmuart_priv *priv = dev_get_drvdata(dev); + int ret; + + ret = clk_prepare_enable(priv->baud_mux_clk); + if (ret) + dev_err(dev, "Error enabling BAUD MUX clock\n"); + + /* + * The hardware goes back to it's default after suspend + * so get the "clk" back in sync. + */ + ret = clk_set_rate(priv->baud_mux_clk, priv->default_mux_rate); + if (ret) + dev_err(dev, "Error restoring default BAUD MUX clock\n"); + if (priv->dma_enabled) { + if (brcmuart_arbitration(priv, 1)) { + dev_err(dev, "Timeout arbitrating for DMA hardware on resume\n"); + return(-EBUSY); + } + brcmuart_init_dma_hardware(priv); + start_rx_dma(serial8250_get_port(priv->line)); + } + serial8250_resume_port(priv->line); + return 0; +} + +static const struct dev_pm_ops brcmuart_dev_pm_ops = { + SET_SYSTEM_SLEEP_PM_OPS(brcmuart_suspend, brcmuart_resume) +}; + +static struct platform_driver brcmuart_platform_driver = { + .driver = { + .name = "bcm7271-uart", + .pm = &brcmuart_dev_pm_ops, + .of_match_table = brcmuart_dt_ids, + }, + .probe = brcmuart_probe, + .remove = brcmuart_remove, +}; + +static int __init brcmuart_init(void) +{ + brcmuart_debugfs_root = debugfs_create_dir( + brcmuart_platform_driver.driver.name, NULL); + return platform_driver_register(&brcmuart_platform_driver); +} +module_init(brcmuart_init); + +static void __exit brcmuart_deinit(void) +{ + platform_driver_unregister(&brcmuart_platform_driver); + debugfs_remove_recursive(brcmuart_debugfs_root); +} +module_exit(brcmuart_deinit); + +MODULE_AUTHOR("Al Cooper"); +MODULE_DESCRIPTION("Broadcom NS16550A compatible serial port driver"); +MODULE_LICENSE("GPL v2"); |