drivers/tty/serial/8250/8250_mid.c

   1 /*
   2  * 8250_mid.c - Driver for UART on Intel Penwell and various other Intel SOCs
   3  *
   4  * Copyright (C) 2015 Intel Corporation
   5  * Author: Heikki Krogerus <heikki.krogerus@linux.intel.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/rational.h>
  13 #include <linux/module.h>
  14 #include <linux/pci.h>
  15
  16 #include <linux/dma/hsu.h>
  17
  18 #include "8250.h"
  19
  20 #define PCI_DEVICE_ID_INTEL_PNW_UART1   0x081b
  21 #define PCI_DEVICE_ID_INTEL_PNW_UART2   0x081c
  22 #define PCI_DEVICE_ID_INTEL_PNW_UART3   0x081d
  23 #define PCI_DEVICE_ID_INTEL_TNG_UART    0x1191
  24 #define PCI_DEVICE_ID_INTEL_DNV_UART    0x19d8
  25
  26 /* Intel MID Specific registers */
  27 #define INTEL_MID_UART_PS               0x30
  28 #define INTEL_MID_UART_MUL              0x34
  29 #define INTEL_MID_UART_DIV              0x38
  30
  31 struct mid8250;
  32
  33 struct mid8250_board {
  34         unsigned long freq;
  35         unsigned int base_baud;
  36         int (*setup)(struct mid8250 *, struct uart_port *p);
  37         void (*exit)(struct mid8250 *);
  38 };
  39
  40 struct mid8250 {
  41         int line;
  42         int dma_index;
  43         struct pci_dev *dma_dev;
  44         struct uart_8250_dma dma;
  45         struct mid8250_board *board;
  46         struct hsu_dma_chip dma_chip;
  47 };
  48
  49 /*****************************************************************************/
  50
  51 static int pnw_setup(struct mid8250 *mid, struct uart_port *p)
  52 {
  53         struct pci_dev *pdev = to_pci_dev(p->dev);
  54
  55         switch (pdev->device) {
  56         case PCI_DEVICE_ID_INTEL_PNW_UART1:
  57                 mid->dma_index = 0;
  58                 break;
  59         case PCI_DEVICE_ID_INTEL_PNW_UART2:
  60                 mid->dma_index = 1;
  61                 break;
  62         case PCI_DEVICE_ID_INTEL_PNW_UART3:
  63                 mid->dma_index = 2;
  64                 break;
  65         default:
  66                 return -EINVAL;
  67         }
  68
  69         mid->dma_dev = pci_get_slot(pdev->bus,
  70                                     PCI_DEVFN(PCI_SLOT(pdev->devfn), 3));
  71         return 0;
  72 }
  73
  74 static int tng_setup(struct mid8250 *mid, struct uart_port *p)
  75 {
  76         struct pci_dev *pdev = to_pci_dev(p->dev);
  77         int index = PCI_FUNC(pdev->devfn);
  78
  79         /* Currently no support for HSU port0 */
  80         if (index-- == 0)
  81                 return -ENODEV;
  82
  83         mid->dma_index = index;
  84         mid->dma_dev = pci_get_slot(pdev->bus, PCI_DEVFN(5, 0));
  85         return 0;
  86 }
  87
  88 static int dnv_handle_irq(struct uart_port *p)
  89 {
  90         struct mid8250 *mid = p->private_data;
  91         int ret;
  92
  93         ret = hsu_dma_irq(&mid->dma_chip, 0);
  94         ret |= hsu_dma_irq(&mid->dma_chip, 1);
  95
  96         /* For now, letting the HW generate separate interrupt for the UART */
  97         if (ret)
  98                 return ret;
  99
 100         return serial8250_handle_irq(p, serial_port_in(p, UART_IIR));
 101 }
 102
 103 #define DNV_DMA_CHAN_OFFSET 0x80
 104
 105 static int dnv_setup(struct mid8250 *mid, struct uart_port *p)
 106 {
 107         struct hsu_dma_chip *chip = &mid->dma_chip;
 108         struct pci_dev *pdev = to_pci_dev(p->dev);
 109         int ret;
 110
 111         chip->dev = &pdev->dev;
 112         chip->irq = pdev->irq;
 113         chip->regs = p->membase;
 114         chip->length = pci_resource_len(pdev, 0);
 115         chip->offset = DNV_DMA_CHAN_OFFSET;
 116
 117         /* Falling back to PIO mode if DMA probing fails */
 118         ret = hsu_dma_probe(chip);
 119         if (ret)
 120                 return 0;
 121
 122         mid->dma_dev = pdev;
 123
 124         p->handle_irq = dnv_handle_irq;
 125         return 0;
 126 }
 127
 128 static void dnv_exit(struct mid8250 *mid)
 129 {
 130         if (!mid->dma_dev)
 131                 return;
 132         hsu_dma_remove(&mid->dma_chip);
 133 }
 134
 135 /*****************************************************************************/
 136
 137 static void mid8250_set_termios(struct uart_port *p,
 138                                 struct ktermios *termios,
 139                                 struct ktermios *old)
 140 {
 141         unsigned int baud = tty_termios_baud_rate(termios);
 142         struct mid8250 *mid = p->private_data;
 143         unsigned short ps = 16;
 144         unsigned long fuart = baud * ps;
 145         unsigned long w = BIT(24) - 1;
 146         unsigned long mul, div;
 147
 148         if (mid->board->freq < fuart) {
 149                 /* Find prescaler value that satisfies Fuart < Fref */
 150                 if (mid->board->freq > baud)
 151                         ps = mid->board->freq / baud;   /* baud rate too high */
 152                 else
 153                         ps = 1;                         /* PLL case */
 154                 fuart = baud * ps;
 155         } else {
 156                 /* Get Fuart closer to Fref */
 157                 fuart *= rounddown_pow_of_two(mid->board->freq / fuart);
 158         }
 159
 160         rational_best_approximation(fuart, mid->board->freq, w, w, &mul, &div);
 161         p->uartclk = fuart * 16 / ps;           /* core uses ps = 16 always */
 162
 163         writel(ps, p->membase + INTEL_MID_UART_PS);             /* set PS */
 164         writel(mul, p->membase + INTEL_MID_UART_MUL);           /* set MUL */
 165         writel(div, p->membase + INTEL_MID_UART_DIV);
 166
 167         serial8250_do_set_termios(p, termios, old);
 168 }
 169
 170 static bool mid8250_dma_filter(struct dma_chan *chan, void *param)
 171 {
 172         struct hsu_dma_slave *s = param;
 173
 174         if (s->dma_dev != chan->device->dev || s->chan_id != chan->chan_id)
 175                 return false;
 176
 177         chan->private = s;
 178         return true;
 179 }
 180
 181 static int mid8250_dma_setup(struct mid8250 *mid, struct uart_8250_port *port)
 182 {
 183         struct uart_8250_dma *dma = &mid->dma;
 184         struct device *dev = port->port.dev;
 185         struct hsu_dma_slave *rx_param;
 186         struct hsu_dma_slave *tx_param;
 187
 188         if (!mid->dma_dev)
 189                 return 0;
 190
 191         rx_param = devm_kzalloc(dev, sizeof(*rx_param), GFP_KERNEL);
 192         if (!rx_param)
 193                 return -ENOMEM;
 194
 195         tx_param = devm_kzalloc(dev, sizeof(*tx_param), GFP_KERNEL);
 196         if (!tx_param)
 197                 return -ENOMEM;
 198
 199         rx_param->chan_id = mid->dma_index * 2 + 1;
 200         tx_param->chan_id = mid->dma_index * 2;
 201
 202         dma->rxconf.src_maxburst = 64;
 203         dma->txconf.dst_maxburst = 64;
 204
 205         rx_param->dma_dev = &mid->dma_dev->dev;
 206         tx_param->dma_dev = &mid->dma_dev->dev;
 207
 208         dma->fn = mid8250_dma_filter;
 209         dma->rx_param = rx_param;
 210         dma->tx_param = tx_param;
 211
 212         port->dma = dma;
 213         return 0;
 214 }
 215
 216 static int mid8250_probe(struct pci_dev *pdev, const struct pci_device_id *id)
 217 {
 218         struct uart_8250_port uart;
 219         struct mid8250 *mid;
 220         int ret;
 221
 222         ret = pcim_enable_device(pdev);
 223         if (ret)
 224                 return ret;
 225
 226         pci_set_master(pdev);
 227
 228         mid = devm_kzalloc(&pdev->dev, sizeof(*mid), GFP_KERNEL);
 229         if (!mid)
 230                 return -ENOMEM;
 231
 232         mid->board = (struct mid8250_board *)id->driver_data;
 233
 234         memset(&uart, 0, sizeof(struct uart_8250_port));
 235
 236         uart.port.dev = &pdev->dev;
 237         uart.port.irq = pdev->irq;
 238         uart.port.private_data = mid;
 239         uart.port.type = PORT_16750;
 240         uart.port.iotype = UPIO_MEM;
 241         uart.port.uartclk = mid->board->base_baud * 16;
 242         uart.port.flags = UPF_SHARE_IRQ | UPF_FIXED_PORT | UPF_FIXED_TYPE;
 243         uart.port.set_termios = mid8250_set_termios;
 244
 245         uart.port.mapbase = pci_resource_start(pdev, 0);
 246         uart.port.membase = pcim_iomap(pdev, 0, 0);
 247         if (!uart.port.membase)
 248                 return -ENOMEM;
 249
 250         if (mid->board->setup) {
 251                 ret = mid->board->setup(mid, &uart.port);
 252                 if (ret)
 253                         return ret;
 254         }
 255
 256         ret = mid8250_dma_setup(mid, &uart);
 257         if (ret)
 258                 goto err;
 259
 260         ret = serial8250_register_8250_port(&uart);
 261         if (ret < 0)
 262                 goto err;
 263
 264         mid->line = ret;
 265
 266         pci_set_drvdata(pdev, mid);
 267         return 0;
 268 err:
 269         if (mid->board->exit)
 270                 mid->board->exit(mid);
 271         return ret;
 272 }
 273
 274 static void mid8250_remove(struct pci_dev *pdev)
 275 {
 276         struct mid8250 *mid = pci_get_drvdata(pdev);
 277
 278         if (mid->board->exit)
 279                 mid->board->exit(mid);
 280
 281         serial8250_unregister_port(mid->line);
 282 }
 283
 284 static const struct mid8250_board pnw_board = {
 285         .freq = 50000000,
 286         .base_baud = 115200,
 287         .setup = pnw_setup,
 288 };
 289
 290 static const struct mid8250_board tng_board = {
 291         .freq = 38400000,
 292         .base_baud = 1843200,
 293         .setup = tng_setup,
 294 };
 295
 296 static const struct mid8250_board dnv_board = {
 297         .freq = 133333333,
 298         .base_baud = 115200,
 299         .setup = dnv_setup,
 300         .exit = dnv_exit,
 301 };
 302
 303 #define MID_DEVICE(id, board) { PCI_VDEVICE(INTEL, id), (kernel_ulong_t)&board }
 304
 305 static const struct pci_device_id pci_ids[] = {
 306         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART1, pnw_board),
 307         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART2, pnw_board),
 308         MID_DEVICE(PCI_DEVICE_ID_INTEL_PNW_UART3, pnw_board),
 309         MID_DEVICE(PCI_DEVICE_ID_INTEL_TNG_UART, tng_board),
 310         MID_DEVICE(PCI_DEVICE_ID_INTEL_DNV_UART, dnv_board),
 311         { },
 312 };
 313 MODULE_DEVICE_TABLE(pci, pci_ids);
 314
 315 static struct pci_driver mid8250_pci_driver = {
 316         .name           = "8250_mid",
 317         .id_table       = pci_ids,
 318         .probe          = mid8250_probe,
 319         .remove         = mid8250_remove,
 320 };
 321
 322 module_pci_driver(mid8250_pci_driver);
 323
 324 MODULE_AUTHOR("Intel Corporation");
 325 MODULE_LICENSE("GPL v2");
 326 MODULE_DESCRIPTION("Intel MID UART driver");