475 lines · c
1// SPDX-License-Identifier: GPL-2.02/*3 * Copyright (C) 2007 Google, Inc.4 * Copyright (C) 2012 Intel, Inc.5 * Copyright (C) 2017 Imagination Technologies Ltd.6 */7 8#include <linux/console.h>9#include <linux/interrupt.h>10#include <linux/platform_device.h>11#include <linux/tty.h>12#include <linux/tty_flip.h>13#include <linux/slab.h>14#include <linux/io.h>15#include <linux/module.h>16#include <linux/mod_devicetable.h>17#include <linux/goldfish.h>18#include <linux/mm.h>19#include <linux/dma-mapping.h>20#include <linux/serial_core.h>21 22/* Goldfish tty register's offsets */23#define GOLDFISH_TTY_REG_BYTES_READY 0x0424#define GOLDFISH_TTY_REG_CMD 0x0825#define GOLDFISH_TTY_REG_DATA_PTR 0x1026#define GOLDFISH_TTY_REG_DATA_LEN 0x1427#define GOLDFISH_TTY_REG_DATA_PTR_HIGH 0x1828#define GOLDFISH_TTY_REG_VERSION 0x2029 30/* Goldfish tty commands */31#define GOLDFISH_TTY_CMD_INT_DISABLE 032#define GOLDFISH_TTY_CMD_INT_ENABLE 133#define GOLDFISH_TTY_CMD_WRITE_BUFFER 234#define GOLDFISH_TTY_CMD_READ_BUFFER 335 36struct goldfish_tty {37 struct tty_port port;38 spinlock_t lock;39 void __iomem *base;40 u32 irq;41 int opencount;42 struct console console;43 u32 version;44 struct device *dev;45};46 47static DEFINE_MUTEX(goldfish_tty_lock);48static struct tty_driver *goldfish_tty_driver;49static u32 goldfish_tty_line_count = 8;50static u32 goldfish_tty_current_line_count;51static struct goldfish_tty *goldfish_ttys;52 53static void do_rw_io(struct goldfish_tty *qtty, unsigned long address,54 size_t count, bool is_write)55{56 unsigned long irq_flags;57 void __iomem *base = qtty->base;58 59 spin_lock_irqsave(&qtty->lock, irq_flags);60 gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR,61 base + GOLDFISH_TTY_REG_DATA_PTR_HIGH);62 gf_iowrite32(count, base + GOLDFISH_TTY_REG_DATA_LEN);63 64 if (is_write)65 gf_iowrite32(GOLDFISH_TTY_CMD_WRITE_BUFFER,66 base + GOLDFISH_TTY_REG_CMD);67 else68 gf_iowrite32(GOLDFISH_TTY_CMD_READ_BUFFER,69 base + GOLDFISH_TTY_REG_CMD);70 71 spin_unlock_irqrestore(&qtty->lock, irq_flags);72}73 74static void goldfish_tty_rw(struct goldfish_tty *qtty, unsigned long addr,75 size_t count, bool is_write)76{77 dma_addr_t dma_handle;78 enum dma_data_direction dma_dir;79 80 dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE);81 if (qtty->version > 0) {82 /*83 * Goldfish TTY for Ranchu platform uses84 * physical addresses and DMA for read/write operations85 */86 unsigned long addr_end = addr + count;87 88 while (addr < addr_end) {89 unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE;90 unsigned long next =91 pg_end < addr_end ? pg_end : addr_end;92 unsigned long avail = next - addr;93 94 /*95 * Map the buffer's virtual address to the DMA address96 * so the buffer can be accessed by the device.97 */98 dma_handle = dma_map_single(qtty->dev, (void *)addr,99 avail, dma_dir);100 101 if (dma_mapping_error(qtty->dev, dma_handle)) {102 dev_err(qtty->dev, "tty: DMA mapping error.\n");103 return;104 }105 do_rw_io(qtty, dma_handle, avail, is_write);106 107 /*108 * Unmap the previously mapped region after109 * the completion of the read/write operation.110 */111 dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir);112 113 addr += avail;114 }115 } else {116 /*117 * Old style Goldfish TTY used on the Goldfish platform118 * uses virtual addresses.119 */120 do_rw_io(qtty, addr, count, is_write);121 }122}123 124static void goldfish_tty_do_write(int line, const u8 *buf, size_t count)125{126 struct goldfish_tty *qtty = &goldfish_ttys[line];127 128 goldfish_tty_rw(qtty, (unsigned long)buf, count, true);129}130 131static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id)132{133 struct goldfish_tty *qtty = dev_id;134 void __iomem *base = qtty->base;135 u8 *buf;136 u32 count;137 138 count = gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY);139 if (count == 0)140 return IRQ_NONE;141 142 count = tty_prepare_flip_string(&qtty->port, &buf, count);143 144 goldfish_tty_rw(qtty, (unsigned long)buf, count, false);145 146 tty_flip_buffer_push(&qtty->port);147 return IRQ_HANDLED;148}149 150static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty)151{152 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,153 port);154 gf_iowrite32(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD);155 return 0;156}157 158static void goldfish_tty_shutdown(struct tty_port *port)159{160 struct goldfish_tty *qtty = container_of(port, struct goldfish_tty,161 port);162 gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD);163}164 165static int goldfish_tty_open(struct tty_struct *tty, struct file *filp)166{167 struct goldfish_tty *qtty = &goldfish_ttys[tty->index];168 return tty_port_open(&qtty->port, tty, filp);169}170 171static void goldfish_tty_close(struct tty_struct *tty, struct file *filp)172{173 tty_port_close(tty->port, tty, filp);174}175 176static void goldfish_tty_hangup(struct tty_struct *tty)177{178 tty_port_hangup(tty->port);179}180 181static ssize_t goldfish_tty_write(struct tty_struct *tty, const u8 *buf,182 size_t count)183{184 goldfish_tty_do_write(tty->index, buf, count);185 return count;186}187 188static unsigned int goldfish_tty_write_room(struct tty_struct *tty)189{190 return 0x10000;191}192 193static unsigned int goldfish_tty_chars_in_buffer(struct tty_struct *tty)194{195 struct goldfish_tty *qtty = &goldfish_ttys[tty->index];196 void __iomem *base = qtty->base;197 return gf_ioread32(base + GOLDFISH_TTY_REG_BYTES_READY);198}199 200static void goldfish_tty_console_write(struct console *co, const char *b,201 unsigned count)202{203 goldfish_tty_do_write(co->index, b, count);204}205 206static struct tty_driver *goldfish_tty_console_device(struct console *c,207 int *index)208{209 *index = c->index;210 return goldfish_tty_driver;211}212 213static int goldfish_tty_console_setup(struct console *co, char *options)214{215 if ((unsigned)co->index >= goldfish_tty_line_count)216 return -ENODEV;217 if (!goldfish_ttys[co->index].base)218 return -ENODEV;219 return 0;220}221 222static const struct tty_port_operations goldfish_port_ops = {223 .activate = goldfish_tty_activate,224 .shutdown = goldfish_tty_shutdown225};226 227static const struct tty_operations goldfish_tty_ops = {228 .open = goldfish_tty_open,229 .close = goldfish_tty_close,230 .hangup = goldfish_tty_hangup,231 .write = goldfish_tty_write,232 .write_room = goldfish_tty_write_room,233 .chars_in_buffer = goldfish_tty_chars_in_buffer,234};235 236static int goldfish_tty_create_driver(void)237{238 int ret;239 struct tty_driver *tty;240 241 goldfish_ttys = kcalloc(goldfish_tty_line_count,242 sizeof(*goldfish_ttys),243 GFP_KERNEL);244 if (goldfish_ttys == NULL) {245 ret = -ENOMEM;246 goto err_alloc_goldfish_ttys_failed;247 }248 tty = tty_alloc_driver(goldfish_tty_line_count,249 TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW |250 TTY_DRIVER_DYNAMIC_DEV);251 if (IS_ERR(tty)) {252 ret = PTR_ERR(tty);253 goto err_tty_alloc_driver_failed;254 }255 tty->driver_name = "goldfish";256 tty->name = "ttyGF";257 tty->type = TTY_DRIVER_TYPE_SERIAL;258 tty->subtype = SERIAL_TYPE_NORMAL;259 tty->init_termios = tty_std_termios;260 tty_set_operations(tty, &goldfish_tty_ops);261 ret = tty_register_driver(tty);262 if (ret)263 goto err_tty_register_driver_failed;264 265 goldfish_tty_driver = tty;266 return 0;267 268err_tty_register_driver_failed:269 tty_driver_kref_put(tty);270err_tty_alloc_driver_failed:271 kfree(goldfish_ttys);272 goldfish_ttys = NULL;273err_alloc_goldfish_ttys_failed:274 return ret;275}276 277static void goldfish_tty_delete_driver(void)278{279 tty_unregister_driver(goldfish_tty_driver);280 tty_driver_kref_put(goldfish_tty_driver);281 goldfish_tty_driver = NULL;282 kfree(goldfish_ttys);283 goldfish_ttys = NULL;284}285 286static int goldfish_tty_probe(struct platform_device *pdev)287{288 struct goldfish_tty *qtty;289 int ret = -ENODEV;290 struct resource *r;291 struct device *ttydev;292 void __iomem *base;293 int irq;294 unsigned int line;295 296 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);297 if (!r) {298 pr_err("goldfish_tty: No MEM resource available!\n");299 return -ENOMEM;300 }301 302 base = ioremap(r->start, 0x1000);303 if (!base) {304 pr_err("goldfish_tty: Unable to ioremap base!\n");305 return -ENOMEM;306 }307 308 irq = platform_get_irq(pdev, 0);309 if (irq < 0) {310 ret = irq;311 goto err_unmap;312 }313 314 mutex_lock(&goldfish_tty_lock);315 316 if (pdev->id == PLATFORM_DEVID_NONE)317 line = goldfish_tty_current_line_count;318 else319 line = pdev->id;320 321 if (line >= goldfish_tty_line_count) {322 pr_err("goldfish_tty: Reached maximum tty number of %d.\n",323 goldfish_tty_current_line_count);324 ret = -ENOMEM;325 goto err_unlock;326 }327 328 if (goldfish_tty_current_line_count == 0) {329 ret = goldfish_tty_create_driver();330 if (ret)331 goto err_unlock;332 }333 goldfish_tty_current_line_count++;334 335 qtty = &goldfish_ttys[line];336 spin_lock_init(&qtty->lock);337 tty_port_init(&qtty->port);338 qtty->port.ops = &goldfish_port_ops;339 qtty->base = base;340 qtty->irq = irq;341 qtty->dev = &pdev->dev;342 343 /*344 * Goldfish TTY device used by the Goldfish emulator345 * should identify itself with 0, forcing the driver346 * to use virtual addresses. Goldfish TTY device347 * on Ranchu emulator (qemu2) returns 1 here and348 * driver will use physical addresses.349 */350 qtty->version = gf_ioread32(base + GOLDFISH_TTY_REG_VERSION);351 352 /*353 * Goldfish TTY device on Ranchu emulator (qemu2)354 * will use DMA for read/write IO operations.355 */356 if (qtty->version > 0) {357 /*358 * Initialize dma_mask to 32-bits.359 */360 if (!pdev->dev.dma_mask)361 pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask;362 ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32));363 if (ret) {364 dev_err(&pdev->dev, "No suitable DMA available.\n");365 goto err_dec_line_count;366 }367 }368 369 gf_iowrite32(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD);370 371 ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED,372 "goldfish_tty", qtty);373 if (ret) {374 pr_err("goldfish_tty: No IRQ available!\n");375 goto err_dec_line_count;376 }377 378 ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver,379 line, &pdev->dev);380 if (IS_ERR(ttydev)) {381 ret = PTR_ERR(ttydev);382 goto err_tty_register_device_failed;383 }384 385 strcpy(qtty->console.name, "ttyGF");386 qtty->console.write = goldfish_tty_console_write;387 qtty->console.device = goldfish_tty_console_device;388 qtty->console.setup = goldfish_tty_console_setup;389 qtty->console.flags = CON_PRINTBUFFER;390 qtty->console.index = line;391 register_console(&qtty->console);392 platform_set_drvdata(pdev, qtty);393 394 mutex_unlock(&goldfish_tty_lock);395 return 0;396 397err_tty_register_device_failed:398 free_irq(irq, qtty);399err_dec_line_count:400 tty_port_destroy(&qtty->port);401 goldfish_tty_current_line_count--;402 if (goldfish_tty_current_line_count == 0)403 goldfish_tty_delete_driver();404err_unlock:405 mutex_unlock(&goldfish_tty_lock);406err_unmap:407 iounmap(base);408 return ret;409}410 411static void goldfish_tty_remove(struct platform_device *pdev)412{413 struct goldfish_tty *qtty = platform_get_drvdata(pdev);414 415 mutex_lock(&goldfish_tty_lock);416 417 unregister_console(&qtty->console);418 tty_unregister_device(goldfish_tty_driver, qtty->console.index);419 iounmap(qtty->base);420 qtty->base = NULL;421 free_irq(qtty->irq, qtty);422 tty_port_destroy(&qtty->port);423 goldfish_tty_current_line_count--;424 if (goldfish_tty_current_line_count == 0)425 goldfish_tty_delete_driver();426 mutex_unlock(&goldfish_tty_lock);427}428 429#ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE430static void gf_early_console_putchar(struct uart_port *port, unsigned char ch)431{432 gf_iowrite32(ch, port->membase);433}434 435static void gf_early_write(struct console *con, const char *s, unsigned int n)436{437 struct earlycon_device *dev = con->data;438 439 uart_console_write(&dev->port, s, n, gf_early_console_putchar);440}441 442static int __init gf_earlycon_setup(struct earlycon_device *device,443 const char *opt)444{445 if (!device->port.membase)446 return -ENODEV;447 448 device->con->write = gf_early_write;449 return 0;450}451 452OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup);453#endif454 455static const struct of_device_id goldfish_tty_of_match[] = {456 { .compatible = "google,goldfish-tty", },457 {},458};459 460MODULE_DEVICE_TABLE(of, goldfish_tty_of_match);461 462static struct platform_driver goldfish_tty_platform_driver = {463 .probe = goldfish_tty_probe,464 .remove_new = goldfish_tty_remove,465 .driver = {466 .name = "goldfish_tty",467 .of_match_table = goldfish_tty_of_match,468 }469};470 471module_platform_driver(goldfish_tty_platform_driver);472 473MODULE_DESCRIPTION("Goldfish TTY Driver");474MODULE_LICENSE("GPL v2");475