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         .chan_allocation_order = CHAN_ALLOCATION_ASCENDING,
 157         .chan_priority = CHAN_PRIORITY_ASCENDING,
 158         .block_size = 4095,
 159         .nr_masters = 1,
 160         .data_width = {4},
 161         .multi_block = {0},
 162 };
 163
 164 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port)
 165 {
 166         struct uart_8250_dma *dma = &lpss->dma;
 167         struct dw_dma_chip *chip = &lpss->dma_chip;
 168         struct dw_dma_slave *param = &lpss->dma_param;
 169         struct pci_dev *pdev = to_pci_dev(port->dev);
 170         int ret;
 171
 172         chip->dev = &pdev->dev;
 173         chip->irq = pci_irq_vector(pdev, 0);
 174         chip->regs = pci_ioremap_bar(pdev, 1);
 175         chip->pdata = &qrk_serial_dma_pdata;
 176
 177         /* Falling back to PIO mode if DMA probing fails */
 178         ret = dw_dma_probe(chip);
 179         if (ret)
 180                 return;
 181
 182         pci_try_set_mwi(pdev);
 183
 184         /* Special DMA address for UART */
 185         dma->rx_dma_addr = 0xfffff000;
 186         dma->tx_dma_addr = 0xfffff000;
 187
 188         param->dma_dev = &pdev->dev;
 189         param->src_id = 0;
 190         param->dst_id = 1;
 191         param->hs_polarity = true;
 192
 193         lpss->dma_maxburst = 8;
 194 }
 195
 196 static void qrk_serial_exit_dma(struct lpss8250 *lpss)
 197 {
 198         struct dw_dma_slave *param = &lpss->dma_param;
 199
 200         if (!param->dma_dev)
 201                 return;
 202         dw_dma_remove(&lpss->dma_chip);
 203 }
 204 #else   /* CONFIG_SERIAL_8250_DMA */
 205 static void qrk_serial_setup_dma(struct lpss8250 *lpss, struct uart_port *port) {}
 206 static void qrk_serial_exit_dma(struct lpss8250 *lpss) {}
 207 #endif  /* !CONFIG_SERIAL_8250_DMA */
 208
 209 static int qrk_serial_setup(struct lpss8250 *lpss, struct uart_port *port)
 210 {
 211         struct pci_dev *pdev = to_pci_dev(port->dev);
 212         int ret;
 213
 214         pci_set_master(pdev);
 215
 216         ret = pci_alloc_irq_vectors(pdev, 1, 1, PCI_IRQ_ALL_TYPES);
 217         if (ret < 0)
 218                 return ret;
 219
 220         port->irq = pci_irq_vector(pdev, 0);
 221
 222         qrk_serial_setup_dma(lpss, port);
 223         return 0;
 224 }
 225
 226 static void qrk_serial_exit(struct lpss8250 *lpss)
 227 {
 228         qrk_serial_exit_dma(lpss);
 229 }
 230
 231 static bool lpss8250_dma_filter(struct dma_chan *chan, void *param)
 232 {
 233         struct dw_dma_slave *dws = param;
 234
 235         if (dws->dma_dev != chan->device->dev)
 236                 return false;
 237
 238         chan->private = dws;
 239         return true;
 240 }
 241
 242 static int lpss8250_dma_setup(struct lpss8250 *lpss, struct uart_8250_port *port)
 243 {
 244         struct uart_8250_dma *dma = &lpss->dma;
 245         struct dw_dma_slave *rx_param, *tx_param;
 246         struct device *dev = port->port.dev;
 247
 248         if (!lpss->dma_param.dma_dev)
 249                 return 0;
 250
 251         rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
 252         if (!rx_param)
 253                 return -ENOMEM;
 254
 255         tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
 256         if (!tx_param)
 257                 return -ENOMEM;
 258
 259         *rx_param = lpss->dma_param;
 260         dma->rxconf.src_maxburst = lpss->dma_maxburst;
 261
 262         *tx_param = lpss->dma_param;
 263         dma->txconf.dst_maxburst = lpss->dma_maxburst;
 264
 265         dma->fn = lpss8250_dma_filter;
 266         dma->rx_param = rx_param;
 267         dma->tx_param = tx_param;
 268
 269         port->dma = dma;
 270         return 0;
 271 }
 272
 273 static int lpss8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 274 {
 275         struct uart_8250_port uart;
 276         struct lpss8250 *lpss;
 277         int ret;
 278
 279         ret = pcim_enable_device(pdev);
 280         if (ret)
 281                 return ret;
 282
 283         lpss = devm_kzalloc(&pdev->dev, sizeof(*lpss), GFP_KERNEL);
 284         if (!lpss)
 285                 return -ENOMEM;
 286
 287         lpss->board = (struct lpss8250_board *)id->driver_data;
 288
 289         memset(&uart, 0, sizeof(struct uart_8250_port));
 290
 291         uart.port.dev = &pdev->dev;
 292         uart.port.irq = pdev->irq;
 293         uart.port.private_data = lpss;
 294         uart.port.type = PORT_16550A;
 295         uart.port.iotype = UPIO_MEM;
 296         uart.port.regshift = 2;
 297         uart.port.uartclk = lpss->board->base_baud * 16;
 298         uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 299         uart.capabilities = UART_CAP_FIFO | UART_CAP_AFE;
 300         uart.port.mapbase = pci_resource_start(pdev, 0);
 301         uart.port.membase = pcim_iomap(pdev, 0, 0);
 302         if (!uart.port.membase)
 303                 return -ENOMEM;
 304
 305         ret = lpss->board->setup(lpss, &uart.port);
 306         if (ret)
 307                 return ret;
 308
 309         ret = lpss8250_dma_setup(lpss, &uart);
 310         if (ret)
 311                 goto err_exit;
 312
 313         ret = serial8250_register_8250_port(&uart);
 314         if (ret < 0)
 315                 goto err_exit;
 316
 317         lpss->line = ret;
 318
 319         pci_set_drvdata(pdev, lpss);
 320         return 0;
 321
 322 err_exit:
 323         if (lpss->board->exit)
 324                 lpss->board->exit(lpss);
 325         return ret;
 326 }
 327
 328 static void lpss8250_remove(struct pci_dev *pdev)
 329 {
 330         struct lpss8250 *lpss = pci_get_drvdata(pdev);
 331
 332         serial8250_unregister_port(lpss->line);
 333
 334         if (lpss->board->exit)
 335                 lpss->board->exit(lpss);
 336 }
 337
 338 static const struct lpss8250_board byt_board = {
 339         .freq = 100000000,
 340         .base_baud = 2764800,
 341         .setup = byt_serial_setup,
 342 };
 343
 344 static const struct lpss8250_board qrk_board = {
 345         .freq = 44236800,
 346         .base_baud = 2764800,
 347         .setup = qrk_serial_setup,
 348         .exit = qrk_serial_exit,
 349 };
 350
 351 #define LPSS_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
 352
 353 static const struct pci_device_id pci_ids[] = {
 354         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_QRK_UARTx, qrk_board),
 355         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART1, byt_board),
 356         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BYT_UART2, byt_board),
 357         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART1, byt_board),
 358         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BSW_UART2, byt_board),
 359         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART1, byt_board),
 360         LPSS_DEVICE(PCI_DEVICE_ID_INTEL_BDW_UART2, byt_board),
 361         { },
 362 };
 363 MODULE_DEVICE_TABLE(pci, pci_ids);
 364
 365 static struct pci_driver lpss8250_pci_driver = {
 366         .name           = "8250_lpss",
 367         .id_table       = pci_ids,
 368         .probe          = lpss8250_probe,
 369         .remove         = lpss8250_remove,
 370 };
 371
 372 module_pci_driver(lpss8250_pci_driver);
 373
 374 MODULE_AUTHOR("Intel Corporation");
 375 MODULE_LICENSE("GPL v2");
 376 MODULE_DESCRIPTION("Intel LPSS UART driver");