| /* |
| * TTY over Blackfin JTAG Communication |
| * |
| * Copyright 2008-2009 Analog Devices Inc. |
| * |
| * Enter bugs at http://blackfin.uclinux.org/ |
| * |
| * Licensed under the GPL-2 or later. |
| */ |
| |
| #define DRV_NAME "bfin-jtag-comm" |
| #define DEV_NAME "ttyBFJC" |
| #define pr_fmt(fmt) DRV_NAME ": " fmt |
| |
| #include <linux/circ_buf.h> |
| #include <linux/console.h> |
| #include <linux/delay.h> |
| #include <linux/err.h> |
| #include <linux/kernel.h> |
| #include <linux/kthread.h> |
| #include <linux/module.h> |
| #include <linux/mutex.h> |
| #include <linux/sched.h> |
| #include <linux/slab.h> |
| #include <linux/tty.h> |
| #include <linux/tty_driver.h> |
| #include <linux/tty_flip.h> |
| #include <linux/atomic.h> |
| |
| #define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); }) |
| |
| /* See the Debug/Emulation chapter in the HRM */ |
| #define EMUDOF 0x00000001 /* EMUDAT_OUT full & valid */ |
| #define EMUDIF 0x00000002 /* EMUDAT_IN full & valid */ |
| #define EMUDOOVF 0x00000004 /* EMUDAT_OUT overflow */ |
| #define EMUDIOVF 0x00000008 /* EMUDAT_IN overflow */ |
| |
| static inline uint32_t bfin_write_emudat(uint32_t emudat) |
| { |
| __asm__ __volatile__("emudat = %0;" : : "d"(emudat)); |
| return emudat; |
| } |
| |
| static inline uint32_t bfin_read_emudat(void) |
| { |
| uint32_t emudat; |
| __asm__ __volatile__("%0 = emudat;" : "=d"(emudat)); |
| return emudat; |
| } |
| |
| static inline uint32_t bfin_write_emudat_chars(char a, char b, char c, char d) |
| { |
| return bfin_write_emudat((a << 0) | (b << 8) | (c << 16) | (d << 24)); |
| } |
| |
| #define CIRC_SIZE 2048 /* see comment in tty_io.c:do_tty_write() */ |
| #define CIRC_MASK (CIRC_SIZE - 1) |
| #define circ_empty(circ) ((circ)->head == (circ)->tail) |
| #define circ_free(circ) CIRC_SPACE((circ)->head, (circ)->tail, CIRC_SIZE) |
| #define circ_cnt(circ) CIRC_CNT((circ)->head, (circ)->tail, CIRC_SIZE) |
| #define circ_byte(circ, idx) ((circ)->buf[(idx) & CIRC_MASK]) |
| |
| static struct tty_driver *bfin_jc_driver; |
| static struct task_struct *bfin_jc_kthread; |
| static struct tty_port port; |
| static volatile struct circ_buf bfin_jc_write_buf; |
| |
| static int |
| bfin_jc_emudat_manager(void *arg) |
| { |
| uint32_t inbound_len = 0, outbound_len = 0; |
| |
| while (!kthread_should_stop()) { |
| struct tty_struct *tty = tty_port_tty_get(&port); |
| /* no one left to give data to, so sleep */ |
| if (tty == NULL && circ_empty(&bfin_jc_write_buf)) { |
| pr_debug("waiting for readers\n"); |
| __set_current_state(TASK_UNINTERRUPTIBLE); |
| schedule(); |
| __set_current_state(TASK_RUNNING); |
| continue; |
| } |
| |
| /* no data available, so just chill */ |
| if (!(bfin_read_DBGSTAT() & EMUDIF) && circ_empty(&bfin_jc_write_buf)) { |
| pr_debug("waiting for data (in_len = %i) (circ: %i %i)\n", |
| inbound_len, bfin_jc_write_buf.tail, bfin_jc_write_buf.head); |
| tty_kref_put(tty); |
| if (inbound_len) |
| schedule(); |
| else |
| schedule_timeout_interruptible(HZ); |
| continue; |
| } |
| |
| /* if incoming data is ready, eat it */ |
| if (bfin_read_DBGSTAT() & EMUDIF) { |
| if (tty != NULL) { |
| uint32_t emudat = bfin_read_emudat(); |
| if (inbound_len == 0) { |
| pr_debug("incoming length: 0x%08x\n", emudat); |
| inbound_len = emudat; |
| } else { |
| size_t num_chars = (4 <= inbound_len ? 4 : inbound_len); |
| pr_debug(" incoming data: 0x%08x (pushing %zu)\n", emudat, num_chars); |
| inbound_len -= num_chars; |
| tty_insert_flip_string(tty, (unsigned char *)&emudat, num_chars); |
| tty_flip_buffer_push(tty); |
| } |
| } |
| } |
| |
| /* if outgoing data is ready, post it */ |
| if (!(bfin_read_DBGSTAT() & EMUDOF) && !circ_empty(&bfin_jc_write_buf)) { |
| if (outbound_len == 0) { |
| outbound_len = circ_cnt(&bfin_jc_write_buf); |
| bfin_write_emudat(outbound_len); |
| pr_debug("outgoing length: 0x%08x\n", outbound_len); |
| } else { |
| int tail = bfin_jc_write_buf.tail; |
| size_t ate = (4 <= outbound_len ? 4 : outbound_len); |
| uint32_t emudat = |
| bfin_write_emudat_chars( |
| circ_byte(&bfin_jc_write_buf, tail + 0), |
| circ_byte(&bfin_jc_write_buf, tail + 1), |
| circ_byte(&bfin_jc_write_buf, tail + 2), |
| circ_byte(&bfin_jc_write_buf, tail + 3) |
| ); |
| bfin_jc_write_buf.tail += ate; |
| outbound_len -= ate; |
| if (tty) |
| tty_wakeup(tty); |
| pr_debug(" outgoing data: 0x%08x (pushing %zu)\n", emudat, ate); |
| } |
| } |
| tty_kref_put(tty); |
| } |
| |
| __set_current_state(TASK_RUNNING); |
| return 0; |
| } |
| |
| static int |
| bfin_jc_open(struct tty_struct *tty, struct file *filp) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&port.lock, flags); |
| port.count++; |
| spin_unlock_irqrestore(&port.lock, flags); |
| tty_port_tty_set(&port, tty); |
| wake_up_process(bfin_jc_kthread); |
| return 0; |
| } |
| |
| static void |
| bfin_jc_close(struct tty_struct *tty, struct file *filp) |
| { |
| unsigned long flags; |
| bool last; |
| |
| spin_lock_irqsave(&port.lock, flags); |
| last = --port.count == 0; |
| spin_unlock_irqrestore(&port.lock, flags); |
| if (last) |
| tty_port_tty_set(&port, NULL); |
| wake_up_process(bfin_jc_kthread); |
| } |
| |
| /* XXX: we dont handle the put_char() case where we must handle count = 1 */ |
| static int |
| bfin_jc_circ_write(const unsigned char *buf, int count) |
| { |
| int i; |
| count = min(count, circ_free(&bfin_jc_write_buf)); |
| pr_debug("going to write chunk of %i bytes\n", count); |
| for (i = 0; i < count; ++i) |
| circ_byte(&bfin_jc_write_buf, bfin_jc_write_buf.head + i) = buf[i]; |
| bfin_jc_write_buf.head += i; |
| return i; |
| } |
| |
| #ifndef CONFIG_BFIN_JTAG_COMM_CONSOLE |
| # define console_lock() |
| # define console_unlock() |
| #endif |
| static int |
| bfin_jc_write(struct tty_struct *tty, const unsigned char *buf, int count) |
| { |
| int i; |
| console_lock(); |
| i = bfin_jc_circ_write(buf, count); |
| console_unlock(); |
| wake_up_process(bfin_jc_kthread); |
| return i; |
| } |
| |
| static void |
| bfin_jc_flush_chars(struct tty_struct *tty) |
| { |
| wake_up_process(bfin_jc_kthread); |
| } |
| |
| static int |
| bfin_jc_write_room(struct tty_struct *tty) |
| { |
| return circ_free(&bfin_jc_write_buf); |
| } |
| |
| static int |
| bfin_jc_chars_in_buffer(struct tty_struct *tty) |
| { |
| return circ_cnt(&bfin_jc_write_buf); |
| } |
| |
| static void |
| bfin_jc_wait_until_sent(struct tty_struct *tty, int timeout) |
| { |
| unsigned long expire = jiffies + timeout; |
| while (!circ_empty(&bfin_jc_write_buf)) { |
| if (signal_pending(current)) |
| break; |
| if (time_after(jiffies, expire)) |
| break; |
| } |
| } |
| |
| static const struct tty_operations bfin_jc_ops = { |
| .open = bfin_jc_open, |
| .close = bfin_jc_close, |
| .write = bfin_jc_write, |
| /*.put_char = bfin_jc_put_char,*/ |
| .flush_chars = bfin_jc_flush_chars, |
| .write_room = bfin_jc_write_room, |
| .chars_in_buffer = bfin_jc_chars_in_buffer, |
| .wait_until_sent = bfin_jc_wait_until_sent, |
| }; |
| |
| static int __init bfin_jc_init(void) |
| { |
| int ret; |
| |
| tty_port_init(&port); |
| |
| bfin_jc_kthread = kthread_create(bfin_jc_emudat_manager, NULL, DRV_NAME); |
| if (IS_ERR(bfin_jc_kthread)) |
| return PTR_ERR(bfin_jc_kthread); |
| |
| ret = -ENOMEM; |
| |
| bfin_jc_write_buf.head = bfin_jc_write_buf.tail = 0; |
| bfin_jc_write_buf.buf = kmalloc(CIRC_SIZE, GFP_KERNEL); |
| if (!bfin_jc_write_buf.buf) |
| goto err_buf; |
| |
| bfin_jc_driver = alloc_tty_driver(1); |
| if (!bfin_jc_driver) |
| goto err_driver; |
| |
| bfin_jc_driver->driver_name = DRV_NAME; |
| bfin_jc_driver->name = DEV_NAME; |
| bfin_jc_driver->type = TTY_DRIVER_TYPE_SERIAL; |
| bfin_jc_driver->subtype = SERIAL_TYPE_NORMAL; |
| bfin_jc_driver->init_termios = tty_std_termios; |
| tty_set_operations(bfin_jc_driver, &bfin_jc_ops); |
| |
| ret = tty_register_driver(bfin_jc_driver); |
| if (ret) |
| goto err; |
| |
| pr_init(KERN_INFO DRV_NAME ": initialized\n"); |
| |
| return 0; |
| |
| err: |
| put_tty_driver(bfin_jc_driver); |
| err_driver: |
| kfree(bfin_jc_write_buf.buf); |
| err_buf: |
| kthread_stop(bfin_jc_kthread); |
| return ret; |
| } |
| module_init(bfin_jc_init); |
| |
| static void __exit bfin_jc_exit(void) |
| { |
| kthread_stop(bfin_jc_kthread); |
| kfree(bfin_jc_write_buf.buf); |
| tty_unregister_driver(bfin_jc_driver); |
| put_tty_driver(bfin_jc_driver); |
| } |
| module_exit(bfin_jc_exit); |
| |
| #if defined(CONFIG_BFIN_JTAG_COMM_CONSOLE) || defined(CONFIG_EARLY_PRINTK) |
| static void |
| bfin_jc_straight_buffer_write(const char *buf, unsigned count) |
| { |
| unsigned ate = 0; |
| while (bfin_read_DBGSTAT() & EMUDOF) |
| continue; |
| bfin_write_emudat(count); |
| while (ate < count) { |
| while (bfin_read_DBGSTAT() & EMUDOF) |
| continue; |
| bfin_write_emudat_chars(buf[ate], buf[ate+1], buf[ate+2], buf[ate+3]); |
| ate += 4; |
| } |
| } |
| #endif |
| |
| #ifdef CONFIG_BFIN_JTAG_COMM_CONSOLE |
| static void |
| bfin_jc_console_write(struct console *co, const char *buf, unsigned count) |
| { |
| if (bfin_jc_kthread == NULL) |
| bfin_jc_straight_buffer_write(buf, count); |
| else |
| bfin_jc_circ_write(buf, count); |
| } |
| |
| static struct tty_driver * |
| bfin_jc_console_device(struct console *co, int *index) |
| { |
| *index = co->index; |
| return bfin_jc_driver; |
| } |
| |
| static struct console bfin_jc_console = { |
| .name = DEV_NAME, |
| .write = bfin_jc_console_write, |
| .device = bfin_jc_console_device, |
| .flags = CON_ANYTIME | CON_PRINTBUFFER, |
| .index = -1, |
| }; |
| |
| static int __init bfin_jc_console_init(void) |
| { |
| register_console(&bfin_jc_console); |
| return 0; |
| } |
| console_initcall(bfin_jc_console_init); |
| #endif |
| |
| #ifdef CONFIG_EARLY_PRINTK |
| static void __init |
| bfin_jc_early_write(struct console *co, const char *buf, unsigned int count) |
| { |
| bfin_jc_straight_buffer_write(buf, count); |
| } |
| |
| static struct __initdata console bfin_jc_early_console = { |
| .name = "early_BFJC", |
| .write = bfin_jc_early_write, |
| .flags = CON_ANYTIME | CON_PRINTBUFFER, |
| .index = -1, |
| }; |
| |
| struct console * __init |
| bfin_jc_early_init(unsigned int port, unsigned int cflag) |
| { |
| return &bfin_jc_early_console; |
| } |
| #endif |
| |
| MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>"); |
| MODULE_DESCRIPTION("TTY over Blackfin JTAG Communication"); |
| MODULE_LICENSE("GPL"); |