1 files changed, 426 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 000000000..1349c161c
--- /dev/null
+++ b/drivers/tty/serial/8250/8250_lpss.c
@@ -0,0 +1,426 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * 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>
+ */
+
+#include <linux/bitops.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/rational.h>
+
+#include <linux/dmaengine.h>
+#include <linux/dma/dw.h>
+
+#include "8250_dwlib.h"
+
+#define PCI_DEVICE_ID_INTEL_QRK_UARTx	0x0936
+
+#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_EHL_UART0	0x4b96
+#define PCI_DEVICE_ID_INTEL_EHL_UART1	0x4b97
+#define PCI_DEVICE_ID_INTEL_EHL_UART2	0x4b98
+#define PCI_DEVICE_ID_INTEL_EHL_UART3	0x4b99
+#define PCI_DEVICE_ID_INTEL_EHL_UART4	0x4b9a
+#define PCI_DEVICE_ID_INTEL_EHL_UART5	0x4b9b
+
+#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);
+	void (*exit)(struct lpss8250 *);
+};
+
+struct lpss8250 {
+	struct dw8250_port_data data;
+	struct lpss8250_board *board;
+
+	/* DMA parameters */
+	struct dw_dma_chip dma_chip;
+	struct dw_dma_slave dma_param;
+	u8 dma_maxburst;
+};
+
+static inline struct lpss8250 *to_lpss8250(struct dw8250_port_data *data)
+{
+	return container_of(data, struct lpss8250, data);
+}
+
+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 = to_lpss8250(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 pci_dev *pdev = to_pci_dev(port->dev);
+	struct pci_dev *dma_dev;
+
+	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;
+	}
+
+	dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(PCI_SLOT(pdev->devfn), 0));
+
+	param->dma_dev = &dma_dev->dev;
+	param->m_master = 0;
+	param->p_master = 1;
+
+	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 void byt_serial_exit(struct lpss8250 *lpss)
+{
+	struct dw_dma_slave *param = &lpss->dma_param;
+
+	/* Paired with pci_get_slot() in the byt_serial_setup() above */
+	put_device(param->dma_dev);
+}
+
+static int ehl_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
+{
+	return 0;
+}
+
+static void ehl_serial_exit(struct lpss8250 *lpss)
+{
+	struct uart_8250_port *up = serial8250_get_port(lpss->data.line);
+
+	up->dma = NULL;
+}
+
+#ifdef CONFIG_SERIAL_8250_DMA
+static const struct dw_dma_platform_data qrk_serial_dma_pdata = {
+	.nr_channels = 2,
+	.chan_allocation_order = CHAN_ALLOCATION_ASCENDING,
+	.chan_priority = CHAN_PRIORITY_ASCENDING,
+	.block_size = 4095,
+	.nr_masters = 1,
+	.data_width = {4},
+	.multi_block = {0},
+};
+
+static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)
+{
+	struct uart_8250_dma *dma = &lpss->data.dma;
+	struct dw_dma_chip *chip = &lpss->dma_chip;
+	struct dw_dma_slave *param = &lpss->dma_param;
+	struct pci_dev *pdev = to_pci_dev(port->dev);
+	int ret;
+
+	chip->pdata = &qrk_serial_dma_pdata;
+	chip->dev = &pdev->dev;
+	chip->id = pdev->devfn;
+	chip->irq = pci_irq_vector(pdev, 0);
+	chip->regs = pci_ioremap_bar(pdev, 1);
+	if (!chip->regs)
+		return;
+
+	/* Falling back to PIO mode if DMA probing fails */
+	ret = dw_dma_probe(chip);
+	if (ret)
+		return;
+
+	pci_try_set_mwi(pdev);
+
+	/* Special DMA address for UART */
+	dma->rx_dma_addr = 0xfffff000;
+	dma->tx_dma_addr = 0xfffff000;
+
+	param->dma_dev = &pdev->dev;
+	param->src_id = 0;
+	param->dst_id = 1;
+	param->hs_polarity = true;
+
+	lpss->dma_maxburst = 8;
+}
+
+static void qrk_serial_exit_dma(struct lpss8250 *lpss)
+{
+	struct dw_dma_chip *chip = &lpss->dma_chip;
+	struct dw_dma_slave *param = &lpss->dma_param;
+
+	if (!param->dma_dev)
+		return;
+
+	dw_dma_remove(chip);
+
+	pci_iounmap(to_pci_dev(chip->dev), chip->regs);
+}
+#else	/* CONFIG_SERIAL_8250_DMA */
+static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {}
+static void qrk_serial_exit_dma(struct lpss8250 *lpss) {}
+#endif	/* !CONFIG_SERIAL_8250_DMA */
+
+static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
+{
+	qrk_serial_setup_dma(lpss, port);
+	return 0;
+}
+
+static void qrk_serial_exit(struct lpss8250 *lpss)
+{
+	qrk_serial_exit_dma(lpss);
+}
+
+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->data.dma;
+	struct dw_dma_slave *rx_param, *tx_param;
+	struct device *dev = port->port.dev;
+
+	if (!lpss->dma_param.dma_dev) {
+		dma = port->dma;
+		if (dma)
+			goto out_configuration_only;
+
+		return 0;
+	}
+
+	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;
+	*tx_param = lpss->dma_param;
+
+	dma->fn = lpss8250_dma_filter;
+	dma->rx_param = rx_param;
+	dma->tx_param = tx_param;
+
+	port->dma = dma;
+
+out_configuration_only:
+	dma->rxconf.src_maxburst = lpss->dma_maxburst;
+	dma->txconf.dst_maxburst = lpss->dma_maxburst;
+
+	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;
+
+	ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
+	if (ret < 0)
+		return ret;
+
+	lpss->board = (struct lpss8250_board *)id->driver_data;
+
+	memset(&uart, 0, sizeof(struct uart_8250_port));
+
+	uart.port.dev = &pdev->dev;
+	uart.port.irq = pci_irq_vector(pdev, 0);
+	uart.port.private_data = &lpss->data;
+	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;
+
+	dw8250_setup_port(&uart.port);
+
+	ret = lpss8250_dma_setup(lpss, &uart);
+	if (ret)
+		goto err_exit;
+
+	ret = serial8250_register_8250_port(&uart);
+	if (ret < 0)
+		goto err_exit;
+
+	lpss->data.line = ret;
+
+	pci_set_drvdata(pdev, lpss);
+	return 0;
+
+err_exit:
+	lpss->board->exit(lpss);
+	pci_free_irq_vectors(pdev);
+	return ret;
+}
+
+static void lpss8250_remove(struct pci_dev *pdev)
+{
+	struct lpss8250 *lpss = pci_get_drvdata(pdev);
+
+	serial8250_unregister_port(lpss->data.line);
+
+	lpss->board->exit(lpss);
+	pci_free_irq_vectors(pdev);
+}
+
+static const struct lpss8250_board byt_board = {
+	.freq = 100000000,
+	.base_baud = 2764800,
+	.setup = byt_serial_setup,
+	.exit = byt_serial_exit,
+};
+
+static const struct lpss8250_board ehl_board = {
+	.freq = 200000000,
+	.base_baud = 12500000,
+	.setup = ehl_serial_setup,
+	.exit = ehl_serial_exit,
+};
+
+static const struct lpss8250_board qrk_board = {
+	.freq = 44236800,
+	.base_baud = 2764800,
+	.setup = qrk_serial_setup,
+	.exit = qrk_serial_exit,
+};
+
+static const struct pci_device_id pci_ids[] = {
+	{ PCI_DEVICE_DATA(INTEL, QRK_UARTx, &qrk_board) },
+	{ PCI_DEVICE_DATA(INTEL, EHL_UART0, &ehl_board) },
+	{ PCI_DEVICE_DATA(INTEL, EHL_UART1, &ehl_board) },
+	{ PCI_DEVICE_DATA(INTEL, EHL_UART2, &ehl_board) },
+	{ PCI_DEVICE_DATA(INTEL, EHL_UART3, &ehl_board) },
+	{ PCI_DEVICE_DATA(INTEL, EHL_UART4, &ehl_board) },
+	{ PCI_DEVICE_DATA(INTEL, EHL_UART5, &ehl_board) },
+	{ PCI_DEVICE_DATA(INTEL, BYT_UART1, &byt_board) },
+	{ PCI_DEVICE_DATA(INTEL, BYT_UART2, &byt_board) },
+	{ PCI_DEVICE_DATA(INTEL, BSW_UART1, &byt_board) },
+	{ PCI_DEVICE_DATA(INTEL, BSW_UART2, &byt_board) },
+	{ PCI_DEVICE_DATA(INTEL, BDW_UART1, &byt_board) },
+	{ PCI_DEVICE_DATA(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");