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.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_BDW_UART1   0x9ce3
  28 #define PCI_DEVICE_ID_INTEL_BDW_UART2   0x9ce4
  29
  30 /* Intel LPSS specific registers */
  31
  32 #define BYT_PRV_CLK                     0x800
  33 #define BYT_PRV_CLK_EN                  BIT(0)
  34 #define BYT_PRV_CLK_M_VAL_SHIFT         1
  35 #define BYT_PRV_CLK_N_VAL_SHIFT         16
  36 #define BYT_PRV_CLK_UPDATE              BIT(31)
  37
  38 #define BYT_TX_OVF_INT                  0x820
  39 #define BYT_TX_OVF_INT_MASK             BIT(1)
  40
  41 struct lpss8250;
  42
  43 struct lpss8250_board {
  44         unsigned long freq;
  45         unsigned int base_baud;
  46         int (*setup)(struct lpss8250 *, struct uart_port *p);
  47         void (*exit)(struct lpss8250 *);
  48 };
  49
  50 struct lpss8250 {
  51         int line;
  52         struct lpss8250_board *board;
  53
  54         /* DMA parameters */
  55         struct uart_8250_dma dma;
  56         struct dw_dma_chip dma_chip;
  57         struct dw_dma_slave dma_param;
  58         u8 dma_maxburst;
  59 };
  60
  61 static void byt_set_termios(struct uart_port *p, struct ktermios *termios,
  62                             struct ktermios *old)
  63 {
  64         unsigned int baud = tty_termios_baud_rate(termios);
  65         struct lpss8250 *lpss = p->private_data;
  66         unsigned long fref = lpss->board->freq, fuart = baud * 16;
  67         unsigned long w = BIT(15) - 1;
  68         unsigned long m, n;
  69         u32 reg;
  70
  71         /* Gracefully handle the B0 case: fall back to B9600 */
  72         fuart = fuart ? fuart : 9600 * 16;
  73
  74         /* Get Fuart closer to Fref */
  75         fuart *= rounddown_pow_of_two(fref / fuart);
  76
  77         /*
  78          * For baud rates 0.5M, 1M, 1.5M, 2M, 2.5M, 3M, 3.5M and 4M the
  79          * dividers must be adjusted.
  80          *
  81          * uartclk = (m / n) * 100 MHz, where m <= n
  82          */
  83         rational_best_approximation(fuart, fref, w, w, &m, &n);
  84         p->uartclk = fuart;
  85
  86         /* Reset the clock */
  87         reg = (m << BYT_PRV_CLK_M_VAL_SHIFT) | (n << BYT_PRV_CLK_N_VAL_SHIFT);
  88         writel(reg, p->membase + BYT_PRV_CLK);
  89         reg |= BYT_PRV_CLK_EN | BYT_PRV_CLK_UPDATE;
  90         writel(reg, p->membase + BYT_PRV_CLK);
  91
  92         p->status &= ~UPSTAT_AUTOCTS;
  93         if (termios->c_cflag & CRTSCTS)
  94                 p->status |= UPSTAT_AUTOCTS;
  95
  96         serial8250_do_set_termios(p, termios, old);
  97 }
  98
  99 static unsigned int byt_get_mctrl(struct uart_port *port)
 100 {
 101         unsigned int ret = serial8250_do_get_mctrl(port);
 102
 103         /* Force DCD and DSR signals to permanently be reported as active */
 104         ret |= TIOCM_CAR | TIOCM_DSR;
 105
 106         return ret;
 107 }
 108
 109 static int byt_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
 110 {
 111         struct dw_dma_slave *param = &lpss->dma_param;
 112         struct uart_8250_port *up = up_to_u8250p(port);
 113         struct pci_dev *pdev = to_pci_dev(port->dev);
 114         unsigned int dma_devfn = PCI_DEVFN(PCI_SLOT(pdev->devfn), 0);
 115         struct pci_dev *dma_dev = pci_get_slot(pdev->bus, dma_devfn);
 116
 117         switch (pdev->device) {
 118         case PCI_DEVICE_ID_INTEL_BYT_UART1:
 119         case PCI_DEVICE_ID_INTEL_BSW_UART1:
 120         case PCI_DEVICE_ID_INTEL_BDW_UART1:
 121                 param->src_id = 3;
 122                 param->dst_id = 2;
 123                 break;
 124         case PCI_DEVICE_ID_INTEL_BYT_UART2:
 125         case PCI_DEVICE_ID_INTEL_BSW_UART2:
 126         case PCI_DEVICE_ID_INTEL_BDW_UART2:
 127                 param->src_id = 5;
 128                 param->dst_id = 4;
 129                 break;
 130         default:
 131                 return -EINVAL;
 132         }
 133
 134         param->dma_dev = &dma_dev->dev;
 135         param->m_master = 0;
 136         param->p_master = 1;
 137
 138         /* TODO: Detect FIFO size automaticaly for DesignWare 8250 */
 139         port->fifosize = 64;
 140         up->tx_loadsz = 64;
 141
 142         lpss->dma_maxburst = 16;
 143
 144         port->set_termios = byt_set_termios;
 145         port->get_mctrl = byt_get_mctrl;
 146
 147         /* Disable TX counter interrupts */
 148         writel(BYT_TX_OVF_INT_MASK, port->membase + BYT_TX_OVF_INT);
 149
 150         return 0;
 151 }
 152
 153 #ifdef CONFIG_SERIAL_8250_DMA
 154 static const struct dw_dma_platform_data qrk_serial_dma_pdata = {
 155         .nr_channels = 2,
 156         .is_private = true,
 157         .chan_allocation_order = CHAN_ALLOCATION_ASCENDING,
 158         .chan_priority = CHAN_PRIORITY_ASCENDING,
 159         .block_size = 4095,
 160         .nr_masters = 1,
 161         .data_width = {4},
 162         .multi_block = {0},
 163 };
 164
 165 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)
 166 {
 167         struct uart_8250_dma *dma = &lpss->dma;
 168         struct dw_dma_chip *chip = &lpss->dma_chip;
 169         struct dw_dma_slave *param = &lpss->dma_param;
 170         struct pci_dev *pdev = to_pci_dev(port->dev);
 171         int ret;
 172
 173         chip->dev = &pdev->dev;
 174         chip->irq = pci_irq_vector(pdev, 0);
 175         chip->regs = pci_ioremap_bar(pdev, 1);
 176         chip->pdata = &qrk_serial_dma_pdata;
 177
 178         /* Falling back to PIO mode if DMA probing fails */
 179         ret = dw_dma_probe(chip);
 180         if (ret)
 181                 return;
 182
 183         pci_try_set_mwi(pdev);
 184
 185         /* Special DMA address for UART */
 186         dma->rx_dma_addr = 0xfffff000;
 187         dma->tx_dma_addr = 0xfffff000;
 188
 189         param->dma_dev = &pdev->dev;
 190         param->src_id = 0;
 191         param->dst_id = 1;
 192         param->hs_polarity = true;
 193
 194         lpss->dma_maxburst = 8;
 195 }
 196
 197 static void qrk_serial_exit_dma(struct lpss8250 *lpss)
 198 {
 199         struct dw_dma_slave *param = &lpss->dma_param;
 200
 201         if (!param->dma_dev)
 202                 return;
 203         dw_dma_remove(&lpss->dma_chip);
 204 }
 205 #else   /* CONFIG_SERIAL_8250_DMA */
 206 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {}
 207 static void qrk_serial_exit_dma(struct lpss8250 *lpss) {}
 208 #endif  /* !CONFIG_SERIAL_8250_DMA */
 209
 210 static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
 211 {
 212         struct pci_dev *pdev = to_pci_dev(port->dev);
 213         int ret;
 214
 215         pci_set_master(pdev);
 216
 217         ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
 218         if (ret < 0)
 219                 return ret;
 220
 221         port->irq = pci_irq_vector(pdev, 0);
 222
 223         qrk_serial_setup_dma(lpss, port);
 224         return 0;
 225 }
 226
 227 static void qrk_serial_exit(struct lpss8250 *lpss)
 228 {
 229         qrk_serial_exit_dma(lpss);
 230 }
 231
 232 static bool lpss8250_dma_filter(struct dma_chan *chan, void *param)
 233 {
 234         struct dw_dma_slave *dws = param;
 235
 236         if (dws->dma_dev != chan->device->dev)
 237                 return false;
 238
 239         chan->private = dws;
 240         return true;
 241 }
 242
 243 static int lpss8250_dma_setup(struct lpss8250 *lpss, struct uart_8250_port *port)
 244 {
 245         struct uart_8250_dma *dma = &lpss->dma;
 246         struct dw_dma_slave *rx_param, *tx_param;
 247         struct device *dev = port->port.dev;
 248
 249         if (!lpss->dma_param.dma_dev)
 250                 return 0;
 251
 252         rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
 253         if (!rx_param)
 254                 return -ENOMEM;
 255
 256         tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
 257         if (!tx_param)
 258                 return -ENOMEM;
 259
 260         *rx_param = lpss->dma_param;
 261         dma->rxconf.src_maxburst = lpss->dma_maxburst;
 262
 263         *tx_param = lpss->dma_param;
 264         dma->txconf.dst_maxburst = lpss->dma_maxburst;
 265
 266         dma->fn = lpss8250_dma_filter;
 267         dma->rx_param = rx_param;
 268         dma->tx_param = tx_param;
 269
 270         port->dma = dma;
 271         return 0;
 272 }
 273
 274 static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 275 {
 276         struct uart_8250_port uart;
 277         struct lpss8250 *lpss;
 278         int ret;
 279
 280         ret = pcim_enable_device(pdev);
 281         if (ret)
 282                 return ret;
 283
 284         lpss = devm_kzalloc(&pdev->dev, sizeof(*lpss), GFP_KERNEL);
 285         if (!lpss)
 286                 return -ENOMEM;
 287
 288         lpss->board = (struct lpss8250_board *)id->driver_data;
 289
 290         memset(&uart, 0, sizeof(struct uart_8250_port));
 291
 292         uart.port.dev = &pdev->dev;
 293         uart.port.irq = pdev->irq;
 294         uart.port.private_data = lpss;
 295         uart.port.type = PORT_16550A;
 296         uart.port.iotype = UPIO_MEM;
 297         uart.port.regshift = 2;
 298         uart.port.uartclk = lpss->board->base_baud * 16;
 299         uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 300         uart.capabilities = UART_CAP_FIFO | UART_CAP_AFE;
 301         uart.port.mapbase = pci_resource_start(pdev, 0);
 302         uart.port.membase = pcim_iomap(pdev, 0, 0);
 303         if (!uart.port.membase)
 304                 return -ENOMEM;
 305
 306         ret = lpss->board->setup(lpss, &uart.port);
 307         if (ret)
 308                 return ret;
 309
 310         ret = lpss8250_dma_setup(lpss, &uart);
 311         if (ret)
 312                 goto err_exit;
 313
 314         ret = serial8250_register_8250_port(&uart);
 315         if (ret < 0)
 316                 goto err_exit;
 317
 318         lpss->line = ret;
 319
 320         pci_set_drvdata(pdev, lpss);
 321         return 0;
 322
 323 err_exit:
 324         if (lpss->board->exit)
 325                 lpss->board->exit(lpss);
 326         return ret;
 327 }
 328
 329 static void lpss8250_remove(struct pci_dev *pdev)
 330 {
 331         struct lpss8250 *lpss = pci_get_drvdata(pdev);
 332
 333         serial8250_unregister_port(lpss->line);
 334
 335         if (lpss->board->exit)
 336                 lpss->board->exit(lpss);
 337 }
 338
 339 static const struct lpss8250_board byt_board = {
 340         .freq = 100000000,
 341         .base_baud = 2764800,
 342         .setup = byt_serial_setup,
 343 };
 344
 345 static const struct lpss8250_board qrk_board = {
 346         .freq = 44236800,
 347         .base_baud = 2764800,
 348         .setup = qrk_serial_setup,
 349         .exit = qrk_serial_exit,
 350 };
 351
 352 #define LPSS_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
 353
 354 static const struct pci_device_id pci_ids[] = {
 355         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_QRK_UARTx, qrk_board),
 356         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART1, byt_board),
 357         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART2, byt_board),
 358         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART1, byt_board),
 359         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART2, byt_board),
 360         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART1, byt_board),
 361         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART2, byt_board),
 362         { },
 363 };
 364 MODULE_DEVICE_TABLE(pci, pci_ids);
 365
 366 static struct pci_driver lpss8250_pci_driver = {
 367         .name           = "8250_lpss",
 368         .id_table       = pci_ids,
 369         .probe          = lpss8250_probe,
 370         .remove         = lpss8250_remove,
 371 };
 372
 373 module_pci_driver(lpss8250_pci_driver);
 374
 375 MODULE_AUTHOR("Intel Corporation");
 376 MODULE_LICENSE("GPL v2");
 377 MODULE_DESCRIPTION("Intel LPSS UART driver");