diff options
Diffstat (limited to 'drivers/tty/serial/8250/8250_lpss.c')
| -rw-r--r-- | drivers/tty/serial/8250/8250_lpss.c | 280 |
1 files changed, 280 insertions, 0 deletions
diff --git a/drivers/tty/serial/8250/8250_lpss.c b/drivers/tty/serial/8250/8250_lpss.c new file mode 100644 index 000000000000..071f8781c65b --- /dev/null +++ b/drivers/tty/serial/8250/8250_lpss.c @@ -0,0 +1,280 @@ +/* + * 8250_lpss.c - Driver for UART on Intel Braswell and various other Intel SoCs + * + * Copyright (C) 2016 Intel Corporation + * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/bitops.h> +#include <linux/module.h> +#include <linux/pci.h> +#include <linux/rational.h> + +#include <linux/dmaengine.h> +#include <linux/platform_data/dma-dw.h> + +#include "8250.h" + +#define PCI_DEVICE_ID_INTEL_BYT_UART1 0x0f0a +#define PCI_DEVICE_ID_INTEL_BYT_UART2 0x0f0c + +#define PCI_DEVICE_ID_INTEL_BSW_UART1 0x228a +#define PCI_DEVICE_ID_INTEL_BSW_UART2 0x228c + +#define PCI_DEVICE_ID_INTEL_BDW_UART1 0x9ce3 +#define PCI_DEVICE_ID_INTEL_BDW_UART2 0x9ce4 + +/* Intel LPSS specific registers */ + +#define BYT_PRV_CLK 0x800 +#define BYT_PRV_CLK_EN BIT(0) +#define BYT_PRV_CLK_M_VAL_SHIFT 1 +#define BYT_PRV_CLK_N_VAL_SHIFT 16 +#define BYT_PRV_CLK_UPDATE BIT(31) + +#define BYT_TX_OVF_INT 0x820 +#define BYT_TX_OVF_INT_MASK BIT(1) + +struct lpss8250; + +struct lpss8250_board { + unsigned long freq; + unsigned int base_baud; + int (*setup)(struct lpss8250 *, struct uart_port *p); +}; + +struct lpss8250 { + int line; + struct lpss8250_board *board; + + /* DMA parameters */ + struct uart_8250_dma dma; + struct dw_dma_slave dma_param; + u8 dma_maxburst; +}; + +static void byt_set_termios(struct uart_port *p, struct ktermios *termios, + struct ktermios *old) +{ + unsigned int baud = tty_termios_baud_rate(termios); + struct lpss8250 *lpss = p->private_data; + unsigned long fref = lpss->board->freq, fuart = baud * 16; + unsigned long w = BIT(15) - 1; + unsigned long m, n; + u32 reg; + + /* Gracefully handle the B0 case: fall back to B9600 */ + fuart = fuart ? fuart : 9600 * 16; + + /* Get Fuart closer to Fref */ + fuart *= rounddown_pow_of_two(fref / fuart); + + /* + * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the + * dividers must be adjusted. + * + * uartclk = (m / n) * 100 MHz, where m <= n + */ + rational_best_approximation(fuart, fref, w, w, &m, &n); + p->uartclk = fuart; + + /* Reset the clock */ + reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT); + writel(reg, p->membase + BYT_PRV_CLK); + reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE; + writel(reg, p->membase + BYT_PRV_CLK); + + p->status &= ~UPSTAT_AUTOCTS; + if (termios->c_cflag & CRTSCTS) + p->status |= UPSTAT_AUTOCTS; + + serial8250_do_set_termios(p, termios, old); +} + +static unsigned int byt_get_mctrl(struct uart_port *port) +{ + unsigned int ret = serial8250_do_get_mctrl(port); + + /* Force DCD and DSR signals to permanently be reported as active */ + ret |= TIOCM_CAR | TIOCM_DSR; + + return ret; +} + +static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port) +{ + struct dw_dma_slave *param = &lpss->dma_param; + struct uart_8250_port *up = up_to_u8250p(port); + struct pci_dev *pdev = to_pci_dev(port->dev); + unsigned int dma_devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0); + struct pci_dev *dma_dev = pci_get_slot(pdev->bus, dma_devfn); + + switch (pdev->device) { + case PCI_DEVICE_ID_INTEL_BYT_UART1: + case PCI_DEVICE_ID_INTEL_BSW_UART1: + case PCI_DEVICE_ID_INTEL_BDW_UART1: + param->src_id = 3; + param->dst_id = 2; + break; + case PCI_DEVICE_ID_INTEL_BYT_UART2: + case PCI_DEVICE_ID_INTEL_BSW_UART2: + case PCI_DEVICE_ID_INTEL_BDW_UART2: + param->src_id = 5; + param->dst_id = 4; + break; + default: + return -EINVAL; + } + + param->dma_dev = &dma_dev->dev; + param->m_master = 0; + param->p_master = 1; + + /* TODO: Detect FIFO size automaticaly for DesignWare 8250 */ + port->fifosize = 64; + up->tx_loadsz = 64; + + lpss->dma_maxburst = 16; + + port->set_termios = byt_set_termios; + port->get_mctrl = byt_get_mctrl; + + /* Disable TX counter interrupts */ + writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT); + + return 0; +} + +static bool lpss8250_dma_filter(struct dma_chan *chan, void *param) +{ + struct dw_dma_slave *dws = param; + + if (dws->dma_dev != chan->device->dev) + return false; + + chan->private = dws; + return true; +} + +static int lpss8250_dma_setup(struct lpss8250 *lpss, struct uart_8250_port *port) +{ + struct uart_8250_dma *dma = &lpss->dma; + struct dw_dma_slave *rx_param, *tx_param; + struct device *dev = port->port.dev; + + rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL); + if (!rx_param) + return -ENOMEM; + + tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL); + if (!tx_param) + return -ENOMEM; + + *rx_param = lpss->dma_param; + dma->rxconf.src_maxburst = lpss->dma_maxburst; + + *tx_param = lpss->dma_param; + dma->txconf.dst_maxburst = lpss->dma_maxburst; + + dma->fn = lpss8250_dma_filter; + dma->rx_param = rx_param; + dma->tx_param = tx_param; + + port->dma = dma; + return 0; +} + +static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id) +{ + struct uart_8250_port uart; + struct lpss8250 *lpss; + int ret; + + ret = pcim_enable_device(pdev); + if (ret) + return ret; + + pci_set_master(pdev); + + lpss = devm_kzalloc(&pdev->dev, sizeof(*lpss), GFP_KERNEL); + if (!lpss) + return -ENOMEM; + + lpss->board = (struct lpss8250_board *)id->driver_data; + + memset(&uart, 0, sizeof(struct uart_8250_port)); + + uart.port.dev = &pdev->dev; + uart.port.irq = pdev->irq; + uart.port.private_data = lpss; + uart.port.type = PORT_16550A; + uart.port.iotype = UPIO_MEM; + uart.port.regshift = 2; + uart.port.uartclk = lpss->board->base_baud * 16; + uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE; + uart.capabilities = UART_CAP_FIFO | UART_CAP_AFE; + uart.port.mapbase = pci_resource_start(pdev, 0); + uart.port.membase = pcim_iomap(pdev, 0, 0); + if (!uart.port.membase) + return -ENOMEM; + + ret = lpss->board->setup(lpss, &uart.port); + if (ret) + return ret; + + ret = lpss8250_dma_setup(lpss, &uart); + if (ret) + return ret; + + ret = serial8250_register_8250_port(&uart); + if (ret < 0) + return ret; + + lpss->line = ret; + + pci_set_drvdata(pdev, lpss); + return 0; +} + +static void lpss8250_remove(struct pci_dev *pdev) +{ + struct lpss8250 *lpss = pci_get_drvdata(pdev); + + serial8250_unregister_port(lpss->line); +} + +static const struct lpss8250_board byt_board = { + .freq = 100000000, + .base_baud = 2764800, + .setup = byt_serial_setup, +}; + +#define LPSS_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board } + +static const struct pci_device_id pci_ids[] = { + LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART1, byt_board), + LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART2, byt_board), + LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART1, byt_board), + LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART2, byt_board), + LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART1, byt_board), + LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART2, byt_board), + { }, +}; +MODULE_DEVICE_TABLE(pci, pci_ids); + +static struct pci_driver lpss8250_pci_driver = { + .name = "8250_lpss", + .id_table = pci_ids, + .probe = lpss8250_probe, + .remove = lpss8250_remove, +}; + +module_pci_driver(lpss8250_pci_driver); + +MODULE_AUTHOR("Intel Corporation"); +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("Intel LPSS UART driver"); |