drivers/tty/serial/8250/8250_lpss.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * 8250_lpss.c - Driver for UART on Intel Braswell and various other Intel SoCs
   4  *
   5  * Copyright (C) 2016 Intel Corporation
   6  * Author: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
   7  */
   8
   9 #include <linux/bitops.h>
  10 #include <linux/module.h>
  11 #include <linux/pci.h>
  12 #include <linux/rational.h>
  13
  14 #include <linux/dmaengine.h>
  15 #include <linux/dma/dw.h>
  16
  17 #include "8250_dwlib.h"
  18
  19 #define PCI_DEVICE_ID_INTEL_QRK_UARTx   0x0936
  20
  21 #define PCI_DEVICE_ID_INTEL_BYT_UART1   0x0f0a
  22 #define PCI_DEVICE_ID_INTEL_BYT_UART2   0x0f0c
  23
  24 #define PCI_DEVICE_ID_INTEL_BSW_UART1   0x228a
  25 #define PCI_DEVICE_ID_INTEL_BSW_UART2   0x228c
  26
  27 #define PCI_DEVICE_ID_INTEL_EHL_UART0   0x4b96
  28 #define PCI_DEVICE_ID_INTEL_EHL_UART1   0x4b97
  29 #define PCI_DEVICE_ID_INTEL_EHL_UART2   0x4b98
  30 #define PCI_DEVICE_ID_INTEL_EHL_UART3   0x4b99
  31 #define PCI_DEVICE_ID_INTEL_EHL_UART4   0x4b9a
  32 #define PCI_DEVICE_ID_INTEL_EHL_UART5   0x4b9b
  33
  34 #define PCI_DEVICE_ID_INTEL_BDW_UART1   0x9ce3
  35 #define PCI_DEVICE_ID_INTEL_BDW_UART2   0x9ce4
  36
  37 /* Intel LPSS specific registers */
  38
  39 #define BYT_PRV_CLK                     0x800
  40 #define BYT_PRV_CLK_EN                  BIT(0)
  41 #define BYT_PRV_CLK_M_VAL_SHIFT         1
  42 #define BYT_PRV_CLK_N_VAL_SHIFT         16
  43 #define BYT_PRV_CLK_UPDATE              BIT(31)
  44
  45 #define BYT_TX_OVF_INT                  0x820
  46 #define BYT_TX_OVF_INT_MASK             BIT(1)
  47
  48 struct lpss8250;
  49
  50 struct lpss8250_board {
  51         unsigned long freq;
  52         unsigned int base_baud;
  53         int (*setup)(struct lpss8250 *, struct uart_port *p);
  54         void (*exit)(struct lpss8250 *);
  55 };
  56
  57 struct lpss8250 {
  58         struct dw8250_port_data data;
  59         struct lpss8250_board *board;
  60
  61         /* DMA parameters */
  62         struct dw_dma_chip dma_chip;
  63         struct dw_dma_slave dma_param;
  64         u8 dma_maxburst;
  65 };
  66
  67 static inline struct lpss8250 *to_lpss8250(struct dw8250_port_data *data)
  68 {
  69         return container_of(data, struct lpss8250, data);
  70 }
  71
  72 static void byt_set_termios(struct uart_port *p, struct ktermios *termios,
  73                             struct ktermios *old)
  74 {
  75         unsigned int baud = tty_termios_baud_rate(termios);
  76         struct lpss8250 *lpss = to_lpss8250(p->private_data);
  77         unsigned long fref = lpss->board->freq, fuart = baud * 16;
  78         unsigned long w = BIT(15) - 1;
  79         unsigned long m, n;
  80         u32 reg;
  81
  82         /* Gracefully handle the B0 case: fall back to B9600 */
  83         fuart = fuart ? fuart : 9600 * 16;
  84
  85         /* Get Fuart closer to Fref */
  86         fuart *= rounddown_pow_of_two(fref / fuart);
  87
  88         /*
  89          * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the
  90          * dividers must be adjusted.
  91          *
  92          * uartclk = (m / n) * 100 MHz, where m <= n
  93          */
  94         rational_best_approximation(fuart, fref, w, w, &m, &n);
  95         p->uartclk = fuart;
  96
  97         /* Reset the clock */
  98         reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT);
  99         writel(reg, p->membase + BYT_PRV_CLK);
 100         reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE;
 101         writel(reg, p->membase + BYT_PRV_CLK);
 102
 103         p->status &= ~UPSTAT_AUTOCTS;
 104         if (termios->c_cflag & CRTSCTS)
 105                 p->status |= UPSTAT_AUTOCTS;
 106
 107         serial8250_do_set_termios(p, termios, old);
 108 }
 109
 110 static unsigned int byt_get_mctrl(struct uart_port *port)
 111 {
 112         unsigned int ret = serial8250_do_get_mctrl(port);
 113
 114         /* Force DCD and DSR signals to permanently be reported as active */
 115         ret |= TIOCM_CAR | TIOCM_DSR;
 116
 117         return ret;
 118 }
 119
 120 static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
 121 {
 122         struct dw_dma_slave *param = &lpss->dma_param;
 123         struct pci_dev *pdev = to_pci_dev(port->dev);
 124         unsigned int dma_devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0);
 125         struct pci_dev *dma_dev = pci_get_slot(pdev->bus, dma_devfn);
 126
 127         switch (pdev->device) {
 128         case PCI_DEVICE_ID_INTEL_BYT_UART1:
 129         case PCI_DEVICE_ID_INTEL_BSW_UART1:
 130         case PCI_DEVICE_ID_INTEL_BDW_UART1:
 131                 param->src_id = 3;
 132                 param->dst_id = 2;
 133                 break;
 134         case PCI_DEVICE_ID_INTEL_BYT_UART2:
 135         case PCI_DEVICE_ID_INTEL_BSW_UART2:
 136         case PCI_DEVICE_ID_INTEL_BDW_UART2:
 137                 param->src_id = 5;
 138                 param->dst_id = 4;
 139                 break;
 140         default:
 141                 return -EINVAL;
 142         }
 143
 144         param->dma_dev = &dma_dev->dev;
 145         param->m_master = 0;
 146         param->p_master = 1;
 147
 148         lpss->dma_maxburst = 16;
 149
 150         port->set_termios = byt_set_termios;
 151         port->get_mctrl = byt_get_mctrl;
 152
 153         /* Disable TX counter interrupts */
 154         writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT);
 155
 156         return 0;
 157 }
 158
 159 #ifdef CONFIG_SERIAL_8250_DMA
 160 static const struct dw_dma_platform_data qrk_serial_dma_pdata = {
 161         .nr_channels = 2,
 162         .chan_allocation_order = CHAN_ALLOCATION_ASCENDING,
 163         .chan_priority = CHAN_PRIORITY_ASCENDING,
 164         .block_size = 4095,
 165         .nr_masters = 1,
 166         .data_width = {4},
 167         .multi_block = {0},
 168 };
 169
 170 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)
 171 {
 172         struct uart_8250_dma *dma = &lpss->data.dma;
 173         struct dw_dma_chip *chip = &lpss->dma_chip;
 174         struct dw_dma_slave *param = &lpss->dma_param;
 175         struct pci_dev *pdev = to_pci_dev(port->dev);
 176         int ret;
 177
 178         chip->pdata = &qrk_serial_dma_pdata;
 179         chip->dev = &pdev->dev;
 180         chip->id = pdev->devfn;
 181         chip->irq = pci_irq_vector(pdev, 0);
 182         chip->regs = pci_ioremap_bar(pdev, 1);
 183         if (!chip->regs)
 184                 return;
 185
 186         /* Falling back to PIO mode if DMA probing fails */
 187         ret = dw_dma_probe(chip);
 188         if (ret)
 189                 return;
 190
 191         pci_try_set_mwi(pdev);
 192
 193         /* Special DMA address for UART */
 194         dma->rx_dma_addr = 0xfffff000;
 195         dma->tx_dma_addr = 0xfffff000;
 196
 197         param->dma_dev = &pdev->dev;
 198         param->src_id = 0;
 199         param->dst_id = 1;
 200         param->hs_polarity = true;
 201
 202         lpss->dma_maxburst = 8;
 203 }
 204
 205 static void qrk_serial_exit_dma(struct lpss8250 *lpss)
 206 {
 207         struct dw_dma_chip *chip = &lpss->dma_chip;
 208         struct dw_dma_slave *param = &lpss->dma_param;
 209
 210         if (!param->dma_dev)
 211                 return;
 212
 213         dw_dma_remove(chip);
 214
 215         pci_iounmap(to_pci_dev(chip->dev), chip->regs);
 216 }
 217 #else   /* CONFIG_SERIAL_8250_DMA */
 218 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {}
 219 static void qrk_serial_exit_dma(struct lpss8250 *lpss) {}
 220 #endif  /* !CONFIG_SERIAL_8250_DMA */
 221
 222 static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
 223 {
 224         qrk_serial_setup_dma(lpss, port);
 225         return 0;
 226 }
 227
 228 static void qrk_serial_exit(struct lpss8250 *lpss)
 229 {
 230         qrk_serial_exit_dma(lpss);
 231 }
 232
 233 static bool lpss8250_dma_filter(struct dma_chan *chan, void *param)
 234 {
 235         struct dw_dma_slave *dws = param;
 236
 237         if (dws->dma_dev != chan->device->dev)
 238                 return false;
 239
 240         chan->private = dws;
 241         return true;
 242 }
 243
 244 static int lpss8250_dma_setup(struct lpss8250 *lpss, struct uart_8250_port *port)
 245 {
 246         struct uart_8250_dma *dma = &lpss->data.dma;
 247         struct dw_dma_slave *rx_param, *tx_param;
 248         struct device *dev = port->port.dev;
 249
 250         if (!lpss->dma_param.dma_dev)
 251                 return 0;
 252
 253         rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
 254         if (!rx_param)
 255                 return -ENOMEM;
 256
 257         tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
 258         if (!tx_param)
 259                 return -ENOMEM;
 260
 261         *rx_param = lpss->dma_param;
 262         dma->rxconf.src_maxburst = lpss->dma_maxburst;
 263
 264         *tx_param = lpss->dma_param;
 265         dma->txconf.dst_maxburst = lpss->dma_maxburst;
 266
 267         dma->fn = lpss8250_dma_filter;
 268         dma->rx_param = rx_param;
 269         dma->tx_param = tx_param;
 270
 271         port->dma = dma;
 272         return 0;
 273 }
 274
 275 static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 276 {
 277         struct uart_8250_port uart;
 278         struct lpss8250 *lpss;
 279         int ret;
 280
 281         ret = pcim_enable_device(pdev);
 282         if (ret)
 283                 return ret;
 284
 285         pci_set_master(pdev);
 286
 287         lpss = devm_kzalloc(&pdev->dev, sizeof(*lpss), GFP_KERNEL);
 288         if (!lpss)
 289                 return -ENOMEM;
 290
 291         ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
 292         if (ret < 0)
 293                 return ret;
 294
 295         lpss->board = (struct lpss8250_board *)id->driver_data;
 296
 297         memset(&uart, 0, sizeof(struct uart_8250_port));
 298
 299         uart.port.dev = &pdev->dev;
 300         uart.port.irq = pci_irq_vector(pdev, 0);
 301         uart.port.private_data = &lpss->data;
 302         uart.port.type = PORT_16550A;
 303         uart.port.iotype = UPIO_MEM;
 304         uart.port.regshift = 2;
 305         uart.port.uartclk = lpss->board->base_baud * 16;
 306         uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 307         uart.capabilities = UART_CAP_FIFO | UART_CAP_AFE;
 308         uart.port.mapbase = pci_resource_start(pdev, 0);
 309         uart.port.membase = pcim_iomap(pdev, 0, 0);
 310         if (!uart.port.membase)
 311                 return -ENOMEM;
 312
 313         ret = lpss->board->setup(lpss, &uart.port);
 314         if (ret)
 315                 return ret;
 316
 317         dw8250_setup_port(&uart.port);
 318
 319         ret = lpss8250_dma_setup(lpss, &uart);
 320         if (ret)
 321                 goto err_exit;
 322
 323         ret = serial8250_register_8250_port(&uart);
 324         if (ret < 0)
 325                 goto err_exit;
 326
 327         lpss->data.line = ret;
 328
 329         pci_set_drvdata(pdev, lpss);
 330         return 0;
 331
 332 err_exit:
 333         if (lpss->board->exit)
 334                 lpss->board->exit(lpss);
 335         pci_free_irq_vectors(pdev);
 336         return ret;
 337 }
 338
 339 static void lpss8250_remove(struct pci_dev *pdev)
 340 {
 341         struct lpss8250 *lpss = pci_get_drvdata(pdev);
 342
 343         serial8250_unregister_port(lpss->data.line);
 344
 345         if (lpss->board->exit)
 346                 lpss->board->exit(lpss);
 347         pci_free_irq_vectors(pdev);
 348 }
 349
 350 static const struct lpss8250_board byt_board = {
 351         .freq = 100000000,
 352         .base_baud = 2764800,
 353         .setup = byt_serial_setup,
 354 };
 355
 356 static const struct lpss8250_board ehl_board = {
 357         .freq = 200000000,
 358         .base_baud = 12500000,
 359 };
 360
 361 static const struct lpss8250_board qrk_board = {
 362         .freq = 44236800,
 363         .base_baud = 2764800,
 364         .setup = qrk_serial_setup,
 365         .exit = qrk_serial_exit,
 366 };
 367
 368 static const struct pci_device_id pci_ids[] = {
 369         { PCI_DEVICE_DATA(INTEL, QRK_UARTx, &qrk_board) },
 370         { PCI_DEVICE_DATA(INTEL, EHL_UART0, &ehl_board) },
 371         { PCI_DEVICE_DATA(INTEL, EHL_UART1, &ehl_board) },
 372         { PCI_DEVICE_DATA(INTEL, EHL_UART2, &ehl_board) },
 373         { PCI_DEVICE_DATA(INTEL, EHL_UART3, &ehl_board) },
 374         { PCI_DEVICE_DATA(INTEL, EHL_UART4, &ehl_board) },
 375         { PCI_DEVICE_DATA(INTEL, EHL_UART5, &ehl_board) },
 376         { PCI_DEVICE_DATA(INTEL, BYT_UART1, &byt_board) },
 377         { PCI_DEVICE_DATA(INTEL, BYT_UART2, &byt_board) },
 378         { PCI_DEVICE_DATA(INTEL, BSW_UART1, &byt_board) },
 379         { PCI_DEVICE_DATA(INTEL, BSW_UART2, &byt_board) },
 380         { PCI_DEVICE_DATA(INTEL, BDW_UART1, &byt_board) },
 381         { PCI_DEVICE_DATA(INTEL, BDW_UART2, &byt_board) },
 382         { }
 383 };
 384 MODULE_DEVICE_TABLE(pci, pci_ids);
 385
 386 static struct pci_driver lpss8250_pci_driver = {
 387         .name           = "8250_lpss",
 388         .id_table       = pci_ids,
 389         .probe          = lpss8250_probe,
 390         .remove         = lpss8250_remove,
 391 };
 392
 393 module_pci_driver(lpss8250_pci_driver);
 394
 395 MODULE_AUTHOR("Intel Corporation");
 396 MODULE_LICENSE("GPL v2");
 397 MODULE_DESCRIPTION("Intel LPSS UART driver");