diff options
| -rw-r--r-- | drivers/char/Kconfig | 13 | ||||
| -rw-r--r-- | drivers/char/Makefile | 1 | ||||
| -rw-r--r-- | drivers/char/bfin_jtag_comm.c | 365 |
3 files changed, 379 insertions, 0 deletions
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig index 735bbe2be51a..02ecfd5fa61c 100644 --- a/drivers/char/Kconfig +++ b/drivers/char/Kconfig @@ -97,6 +97,19 @@ config DEVKMEM kind of kernel debugging operations. When in doubt, say "N". +config BFIN_JTAG_COMM + tristate "Blackfin JTAG Communication" + depends on BLACKFIN + help + Add support for emulating a TTY device over the Blackfin JTAG. + + To compile this driver as a module, choose M here: the + module will be called bfin_jtag_comm. + +config BFIN_JTAG_COMM_CONSOLE + bool "Console on Blackfin JTAG" + depends on BFIN_JTAG_COMM=y + config SERIAL_NONSTANDARD bool "Non-standard serial port support" depends on HAS_IOMEM diff --git a/drivers/char/Makefile b/drivers/char/Makefile index 9caf5b5ad1c0..189efcff08ce 100644 --- a/drivers/char/Makefile +++ b/drivers/char/Makefile @@ -13,6 +13,7 @@ obj-$(CONFIG_LEGACY_PTYS) += pty.o obj-$(CONFIG_UNIX98_PTYS) += pty.o obj-y += misc.o obj-$(CONFIG_VT) += vt_ioctl.o vc_screen.o selection.o keyboard.o +obj-$(CONFIG_BFIN_JTAG_COMM) += bfin_jtag_comm.o obj-$(CONFIG_CONSOLE_TRANSLATIONS) += consolemap.o consolemap_deftbl.o obj-$(CONFIG_HW_CONSOLE) += vt.o defkeymap.o obj-$(CONFIG_AUDIT) += tty_audit.o diff --git a/drivers/char/bfin_jtag_comm.c b/drivers/char/bfin_jtag_comm.c new file mode 100644 index 000000000000..44c113d56045 --- /dev/null +++ b/drivers/char/bfin_jtag_comm.c @@ -0,0 +1,365 @@ +/* + * 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. + */ + +#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/tty.h> +#include <linux/tty_driver.h> +#include <linux/tty_flip.h> +#include <asm/atomic.h> + +/* 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 */ + +#define DRV_NAME "bfin-jtag-comm" +#define DEV_NAME "ttyBFJC" + +#define pr_init(fmt, args...) ({ static const __initdata char __fmt[] = fmt; printk(__fmt, ## args); }) +#define debug(fmt, args...) pr_debug(DRV_NAME ": " fmt, ## args) + +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_struct * volatile bfin_jc_tty; +static unsigned long bfin_jc_count; +static DEFINE_MUTEX(bfin_jc_tty_mutex); +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()) { + /* no one left to give data to, so sleep */ + if (bfin_jc_tty == NULL && circ_empty(&bfin_jc_write_buf)) { + debug("waiting for readers\n"); + __set_current_state(TASK_UNINTERRUPTIBLE); + schedule(); + __set_current_state(TASK_RUNNING); + } + + /* no data available, so just chill */ + if (!(bfin_read_DBGSTAT() & EMUDIF) && circ_empty(&bfin_jc_write_buf)) { + debug("waiting for data (in_len = %i) (circ: %i %i)\n", + inbound_len, bfin_jc_write_buf.tail, bfin_jc_write_buf.head); + if (inbound_len) + schedule(); + else + schedule_timeout_interruptible(HZ); + continue; + } + + /* if incoming data is ready, eat it */ + if (bfin_read_DBGSTAT() & EMUDIF) { + struct tty_struct *tty; + mutex_lock(&bfin_jc_tty_mutex); + tty = (struct tty_struct *)bfin_jc_tty; + if (tty != NULL) { + uint32_t emudat = bfin_read_emudat(); + if (inbound_len == 0) { + debug("incoming length: 0x%08x\n", emudat); + inbound_len = emudat; + } else { + size_t num_chars = (4 <= inbound_len ? 4 : inbound_len); + 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); + } + } + mutex_unlock(&bfin_jc_tty_mutex); + } + + /* 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); + debug("outgoing length: 0x%08x\n", outbound_len); + } else { + struct tty_struct *tty; + 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; + mutex_lock(&bfin_jc_tty_mutex); + tty = (struct tty_struct *)bfin_jc_tty; + if (tty) + tty_wakeup(tty); + mutex_unlock(&bfin_jc_tty_mutex); + debug(" outgoing data: 0x%08x (pushing %zu)\n", emudat, ate); + } + } + } + + __set_current_state(TASK_RUNNING); + return 0; +} + +static int +bfin_jc_open(struct tty_struct *tty, struct file *filp) +{ + mutex_lock(&bfin_jc_tty_mutex); + debug("open %lu\n", bfin_jc_count); + ++bfin_jc_count; + bfin_jc_tty = tty; + wake_up_process(bfin_jc_kthread); + mutex_unlock(&bfin_jc_tty_mutex); + return 0; +} + +static void +bfin_jc_close(struct tty_struct *tty, struct file *filp) +{ + mutex_lock(&bfin_jc_tty_mutex); + debug("close %lu\n", bfin_jc_count); + if (--bfin_jc_count == 0) + bfin_jc_tty = NULL; + wake_up_process(bfin_jc_kthread); + mutex_unlock(&bfin_jc_tty_mutex); +} + +/* 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)); + 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 acquire_console_sem() +# define release_console_sem() +#endif +static int +bfin_jc_write(struct tty_struct *tty, const unsigned char *buf, int count) +{ + int i; + acquire_console_sem(); + i = bfin_jc_circ_write(buf, count); + release_console_sem(); + 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 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; + + 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; + + bfin_jc_driver = alloc_tty_driver(1); + if (!bfin_jc_driver) + goto err; + + bfin_jc_driver->owner = THIS_MODULE; + 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); + kfree(bfin_jc_write_buf.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"); |