| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 2007 Google, Inc. |
| * Copyright (C) 2012 Intel, Inc. |
| * Copyright (C) 2017 Imagination Technologies Ltd. |
| */ |
| |
| #include <linux/console.h> |
| #include <linux/interrupt.h> |
| #include <linux/platform_device.h> |
| #include <linux/tty.h> |
| #include <linux/tty_flip.h> |
| #include <linux/slab.h> |
| #include <linux/io.h> |
| #include <linux/module.h> |
| #include <linux/mod_devicetable.h> |
| #include <linux/goldfish.h> |
| #include <linux/mm.h> |
| #include <linux/dma-mapping.h> |
| #include <linux/serial_core.h> |
| |
| /* Goldfish tty register's offsets */ |
| #define GOLDFISH_TTY_REG_BYTES_READY 0x04 |
| #define GOLDFISH_TTY_REG_CMD 0x08 |
| #define GOLDFISH_TTY_REG_DATA_PTR 0x10 |
| #define GOLDFISH_TTY_REG_DATA_LEN 0x14 |
| #define GOLDFISH_TTY_REG_DATA_PTR_HIGH 0x18 |
| #define GOLDFISH_TTY_REG_VERSION 0x20 |
| |
| /* Goldfish tty commands */ |
| #define GOLDFISH_TTY_CMD_INT_DISABLE 0 |
| #define GOLDFISH_TTY_CMD_INT_ENABLE 1 |
| #define GOLDFISH_TTY_CMD_WRITE_BUFFER 2 |
| #define GOLDFISH_TTY_CMD_READ_BUFFER 3 |
| |
| struct goldfish_tty { |
| struct tty_port port; |
| spinlock_t lock; |
| void __iomem *base; |
| u32 irq; |
| int opencount; |
| struct console console; |
| u32 version; |
| struct device *dev; |
| }; |
| |
| static DEFINE_MUTEX(goldfish_tty_lock); |
| static struct tty_driver *goldfish_tty_driver; |
| static u32 goldfish_tty_line_count = 8; |
| static u32 goldfish_tty_current_line_count; |
| static struct goldfish_tty *goldfish_ttys; |
| |
| static void do_rw_io(struct goldfish_tty *qtty, |
| unsigned long address, |
| unsigned int count, |
| int is_write) |
| { |
| unsigned long irq_flags; |
| void __iomem *base = qtty->base; |
| |
| spin_lock_irqsave(&qtty->lock, irq_flags); |
| gf_write_ptr((void *)address, base + GOLDFISH_TTY_REG_DATA_PTR, |
| base + GOLDFISH_TTY_REG_DATA_PTR_HIGH); |
| __raw_writel(count, base + GOLDFISH_TTY_REG_DATA_LEN); |
| |
| if (is_write) |
| __raw_writel(GOLDFISH_TTY_CMD_WRITE_BUFFER, |
| base + GOLDFISH_TTY_REG_CMD); |
| else |
| __raw_writel(GOLDFISH_TTY_CMD_READ_BUFFER, |
| base + GOLDFISH_TTY_REG_CMD); |
| |
| spin_unlock_irqrestore(&qtty->lock, irq_flags); |
| } |
| |
| static void goldfish_tty_rw(struct goldfish_tty *qtty, |
| unsigned long addr, |
| unsigned int count, |
| int is_write) |
| { |
| dma_addr_t dma_handle; |
| enum dma_data_direction dma_dir; |
| |
| dma_dir = (is_write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); |
| if (qtty->version > 0) { |
| /* |
| * Goldfish TTY for Ranchu platform uses |
| * physical addresses and DMA for read/write operations |
| */ |
| unsigned long addr_end = addr + count; |
| |
| while (addr < addr_end) { |
| unsigned long pg_end = (addr & PAGE_MASK) + PAGE_SIZE; |
| unsigned long next = |
| pg_end < addr_end ? pg_end : addr_end; |
| unsigned long avail = next - addr; |
| |
| /* |
| * Map the buffer's virtual address to the DMA address |
| * so the buffer can be accessed by the device. |
| */ |
| dma_handle = dma_map_single(qtty->dev, (void *)addr, |
| avail, dma_dir); |
| |
| if (dma_mapping_error(qtty->dev, dma_handle)) { |
| dev_err(qtty->dev, "tty: DMA mapping error.\n"); |
| return; |
| } |
| do_rw_io(qtty, dma_handle, avail, is_write); |
| |
| /* |
| * Unmap the previously mapped region after |
| * the completion of the read/write operation. |
| */ |
| dma_unmap_single(qtty->dev, dma_handle, avail, dma_dir); |
| |
| addr += avail; |
| } |
| } else { |
| /* |
| * Old style Goldfish TTY used on the Goldfish platform |
| * uses virtual addresses. |
| */ |
| do_rw_io(qtty, addr, count, is_write); |
| } |
| } |
| |
| static void goldfish_tty_do_write(int line, const char *buf, |
| unsigned int count) |
| { |
| struct goldfish_tty *qtty = &goldfish_ttys[line]; |
| unsigned long address = (unsigned long)(void *)buf; |
| |
| goldfish_tty_rw(qtty, address, count, 1); |
| } |
| |
| static irqreturn_t goldfish_tty_interrupt(int irq, void *dev_id) |
| { |
| struct goldfish_tty *qtty = dev_id; |
| void __iomem *base = qtty->base; |
| unsigned long address; |
| unsigned char *buf; |
| u32 count; |
| |
| count = __raw_readl(base + GOLDFISH_TTY_REG_BYTES_READY); |
| if (count == 0) |
| return IRQ_NONE; |
| |
| count = tty_prepare_flip_string(&qtty->port, &buf, count); |
| |
| address = (unsigned long)(void *)buf; |
| goldfish_tty_rw(qtty, address, count, 0); |
| |
| tty_schedule_flip(&qtty->port); |
| return IRQ_HANDLED; |
| } |
| |
| static int goldfish_tty_activate(struct tty_port *port, struct tty_struct *tty) |
| { |
| struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, |
| port); |
| __raw_writel(GOLDFISH_TTY_CMD_INT_ENABLE, qtty->base + GOLDFISH_TTY_REG_CMD); |
| return 0; |
| } |
| |
| static void goldfish_tty_shutdown(struct tty_port *port) |
| { |
| struct goldfish_tty *qtty = container_of(port, struct goldfish_tty, |
| port); |
| __raw_writel(GOLDFISH_TTY_CMD_INT_DISABLE, qtty->base + GOLDFISH_TTY_REG_CMD); |
| } |
| |
| static int goldfish_tty_open(struct tty_struct *tty, struct file *filp) |
| { |
| struct goldfish_tty *qtty = &goldfish_ttys[tty->index]; |
| return tty_port_open(&qtty->port, tty, filp); |
| } |
| |
| static void goldfish_tty_close(struct tty_struct *tty, struct file *filp) |
| { |
| tty_port_close(tty->port, tty, filp); |
| } |
| |
| static void goldfish_tty_hangup(struct tty_struct *tty) |
| { |
| tty_port_hangup(tty->port); |
| } |
| |
| static int goldfish_tty_write(struct tty_struct *tty, const unsigned char *buf, |
| int count) |
| { |
| goldfish_tty_do_write(tty->index, buf, count); |
| return count; |
| } |
| |
| static unsigned int goldfish_tty_write_room(struct tty_struct *tty) |
| { |
| return 0x10000; |
| } |
| |
| static unsigned int goldfish_tty_chars_in_buffer(struct tty_struct *tty) |
| { |
| struct goldfish_tty *qtty = &goldfish_ttys[tty->index]; |
| void __iomem *base = qtty->base; |
| return __raw_readl(base + GOLDFISH_TTY_REG_BYTES_READY); |
| } |
| |
| static void goldfish_tty_console_write(struct console *co, const char *b, |
| unsigned count) |
| { |
| goldfish_tty_do_write(co->index, b, count); |
| } |
| |
| static struct tty_driver *goldfish_tty_console_device(struct console *c, |
| int *index) |
| { |
| *index = c->index; |
| return goldfish_tty_driver; |
| } |
| |
| static int goldfish_tty_console_setup(struct console *co, char *options) |
| { |
| if ((unsigned)co->index >= goldfish_tty_line_count) |
| return -ENODEV; |
| if (!goldfish_ttys[co->index].base) |
| return -ENODEV; |
| return 0; |
| } |
| |
| static const struct tty_port_operations goldfish_port_ops = { |
| .activate = goldfish_tty_activate, |
| .shutdown = goldfish_tty_shutdown |
| }; |
| |
| static const struct tty_operations goldfish_tty_ops = { |
| .open = goldfish_tty_open, |
| .close = goldfish_tty_close, |
| .hangup = goldfish_tty_hangup, |
| .write = goldfish_tty_write, |
| .write_room = goldfish_tty_write_room, |
| .chars_in_buffer = goldfish_tty_chars_in_buffer, |
| }; |
| |
| static int goldfish_tty_create_driver(void) |
| { |
| int ret; |
| struct tty_driver *tty; |
| |
| goldfish_ttys = kcalloc(goldfish_tty_line_count, |
| sizeof(*goldfish_ttys), |
| GFP_KERNEL); |
| if (goldfish_ttys == NULL) { |
| ret = -ENOMEM; |
| goto err_alloc_goldfish_ttys_failed; |
| } |
| tty = alloc_tty_driver(goldfish_tty_line_count); |
| if (tty == NULL) { |
| ret = -ENOMEM; |
| goto err_alloc_tty_driver_failed; |
| } |
| tty->driver_name = "goldfish"; |
| tty->name = "ttyGF"; |
| tty->type = TTY_DRIVER_TYPE_SERIAL; |
| tty->subtype = SERIAL_TYPE_NORMAL; |
| tty->init_termios = tty_std_termios; |
| tty->flags = TTY_DRIVER_RESET_TERMIOS | TTY_DRIVER_REAL_RAW | |
| TTY_DRIVER_DYNAMIC_DEV; |
| tty_set_operations(tty, &goldfish_tty_ops); |
| ret = tty_register_driver(tty); |
| if (ret) |
| goto err_tty_register_driver_failed; |
| |
| goldfish_tty_driver = tty; |
| return 0; |
| |
| err_tty_register_driver_failed: |
| put_tty_driver(tty); |
| err_alloc_tty_driver_failed: |
| kfree(goldfish_ttys); |
| goldfish_ttys = NULL; |
| err_alloc_goldfish_ttys_failed: |
| return ret; |
| } |
| |
| static void goldfish_tty_delete_driver(void) |
| { |
| tty_unregister_driver(goldfish_tty_driver); |
| put_tty_driver(goldfish_tty_driver); |
| goldfish_tty_driver = NULL; |
| kfree(goldfish_ttys); |
| goldfish_ttys = NULL; |
| } |
| |
| static int goldfish_tty_probe(struct platform_device *pdev) |
| { |
| struct goldfish_tty *qtty; |
| int ret = -ENODEV; |
| struct resource *r; |
| struct device *ttydev; |
| void __iomem *base; |
| u32 irq; |
| unsigned int line; |
| |
| r = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| if (!r) { |
| pr_err("goldfish_tty: No MEM resource available!\n"); |
| return -ENOMEM; |
| } |
| |
| base = ioremap(r->start, 0x1000); |
| if (!base) { |
| pr_err("goldfish_tty: Unable to ioremap base!\n"); |
| return -ENOMEM; |
| } |
| |
| r = platform_get_resource(pdev, IORESOURCE_IRQ, 0); |
| if (!r) { |
| pr_err("goldfish_tty: No IRQ resource available!\n"); |
| goto err_unmap; |
| } |
| |
| irq = r->start; |
| |
| mutex_lock(&goldfish_tty_lock); |
| |
| if (pdev->id == PLATFORM_DEVID_NONE) |
| line = goldfish_tty_current_line_count; |
| else |
| line = pdev->id; |
| |
| if (line >= goldfish_tty_line_count) { |
| pr_err("goldfish_tty: Reached maximum tty number of %d.\n", |
| goldfish_tty_current_line_count); |
| ret = -ENOMEM; |
| goto err_unlock; |
| } |
| |
| if (goldfish_tty_current_line_count == 0) { |
| ret = goldfish_tty_create_driver(); |
| if (ret) |
| goto err_unlock; |
| } |
| goldfish_tty_current_line_count++; |
| |
| qtty = &goldfish_ttys[line]; |
| spin_lock_init(&qtty->lock); |
| tty_port_init(&qtty->port); |
| qtty->port.ops = &goldfish_port_ops; |
| qtty->base = base; |
| qtty->irq = irq; |
| qtty->dev = &pdev->dev; |
| |
| /* |
| * Goldfish TTY device used by the Goldfish emulator |
| * should identify itself with 0, forcing the driver |
| * to use virtual addresses. Goldfish TTY device |
| * on Ranchu emulator (qemu2) returns 1 here and |
| * driver will use physical addresses. |
| */ |
| qtty->version = __raw_readl(base + GOLDFISH_TTY_REG_VERSION); |
| |
| /* |
| * Goldfish TTY device on Ranchu emulator (qemu2) |
| * will use DMA for read/write IO operations. |
| */ |
| if (qtty->version > 0) { |
| /* |
| * Initialize dma_mask to 32-bits. |
| */ |
| if (!pdev->dev.dma_mask) |
| pdev->dev.dma_mask = &pdev->dev.coherent_dma_mask; |
| ret = dma_set_mask(&pdev->dev, DMA_BIT_MASK(32)); |
| if (ret) { |
| dev_err(&pdev->dev, "No suitable DMA available.\n"); |
| goto err_dec_line_count; |
| } |
| } |
| |
| __raw_writel(GOLDFISH_TTY_CMD_INT_DISABLE, base + GOLDFISH_TTY_REG_CMD); |
| |
| ret = request_irq(irq, goldfish_tty_interrupt, IRQF_SHARED, |
| "goldfish_tty", qtty); |
| if (ret) { |
| pr_err("goldfish_tty: No IRQ available!\n"); |
| goto err_dec_line_count; |
| } |
| |
| ttydev = tty_port_register_device(&qtty->port, goldfish_tty_driver, |
| line, &pdev->dev); |
| if (IS_ERR(ttydev)) { |
| ret = PTR_ERR(ttydev); |
| goto err_tty_register_device_failed; |
| } |
| |
| strcpy(qtty->console.name, "ttyGF"); |
| qtty->console.write = goldfish_tty_console_write; |
| qtty->console.device = goldfish_tty_console_device; |
| qtty->console.setup = goldfish_tty_console_setup; |
| qtty->console.flags = CON_PRINTBUFFER; |
| qtty->console.index = line; |
| register_console(&qtty->console); |
| platform_set_drvdata(pdev, qtty); |
| |
| mutex_unlock(&goldfish_tty_lock); |
| return 0; |
| |
| err_tty_register_device_failed: |
| free_irq(irq, qtty); |
| err_dec_line_count: |
| goldfish_tty_current_line_count--; |
| if (goldfish_tty_current_line_count == 0) |
| goldfish_tty_delete_driver(); |
| err_unlock: |
| mutex_unlock(&goldfish_tty_lock); |
| err_unmap: |
| iounmap(base); |
| return ret; |
| } |
| |
| static int goldfish_tty_remove(struct platform_device *pdev) |
| { |
| struct goldfish_tty *qtty = platform_get_drvdata(pdev); |
| |
| mutex_lock(&goldfish_tty_lock); |
| |
| unregister_console(&qtty->console); |
| tty_unregister_device(goldfish_tty_driver, qtty->console.index); |
| iounmap(qtty->base); |
| qtty->base = NULL; |
| free_irq(qtty->irq, pdev); |
| goldfish_tty_current_line_count--; |
| if (goldfish_tty_current_line_count == 0) |
| goldfish_tty_delete_driver(); |
| mutex_unlock(&goldfish_tty_lock); |
| return 0; |
| } |
| |
| #ifdef CONFIG_GOLDFISH_TTY_EARLY_CONSOLE |
| static void gf_early_console_putchar(struct uart_port *port, int ch) |
| { |
| __raw_writel(ch, port->membase); |
| } |
| |
| static void gf_early_write(struct console *con, const char *s, unsigned int n) |
| { |
| struct earlycon_device *dev = con->data; |
| |
| uart_console_write(&dev->port, s, n, gf_early_console_putchar); |
| } |
| |
| static int __init gf_earlycon_setup(struct earlycon_device *device, |
| const char *opt) |
| { |
| if (!device->port.membase) |
| return -ENODEV; |
| |
| device->con->write = gf_early_write; |
| return 0; |
| } |
| |
| OF_EARLYCON_DECLARE(early_gf_tty, "google,goldfish-tty", gf_earlycon_setup); |
| #endif |
| |
| static const struct of_device_id goldfish_tty_of_match[] = { |
| { .compatible = "google,goldfish-tty", }, |
| {}, |
| }; |
| |
| MODULE_DEVICE_TABLE(of, goldfish_tty_of_match); |
| |
| static struct platform_driver goldfish_tty_platform_driver = { |
| .probe = goldfish_tty_probe, |
| .remove = goldfish_tty_remove, |
| .driver = { |
| .name = "goldfish_tty", |
| .of_match_table = goldfish_tty_of_match, |
| } |
| }; |
| |
| module_platform_driver(goldfish_tty_platform_driver); |
| |
| MODULE_LICENSE("GPL v2"); |