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![Greg Kroah-Hartman](/assets/img/avatar_default.png)
Now that the SPDX tag is in all tty files, that identifies the license in a specific and legally-defined manner. So the extra GPL text wording can be removed as it is no longer needed at all. This is done on a quest to remove the 700+ different ways that files in the kernel describe the GPL license text. And there's unneeded stuff like the address (sometimes incorrect) for the FSF which is never needed. No copyright headers or other non-license-description text was removed. Cc: Jiri Slaby <jslaby@suse.com> Cc: James Hogan <jhogan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
353 lines
9 KiB
C
353 lines
9 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* TTY over Blackfin JTAG Communication
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*
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* Copyright 2008-2009 Analog Devices Inc.
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*
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* Enter bugs at http://blackfin.uclinux.org/
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*/
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#define DRV_NAME "bfin-jtag-comm"
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#define DEV_NAME "ttyBFJC"
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#define pr_fmt(fmt) DRV_NAME ": " fmt
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#include <linux/circ_buf.h>
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#include <linux/console.h>
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#include <linux/delay.h>
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/kthread.h>
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#include <linux/module.h>
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#include <linux/mutex.h>
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#include <linux/sched.h>
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#include <linux/slab.h>
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#include <linux/tty.h>
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#include <linux/tty_driver.h>
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#include <linux/tty_flip.h>
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#include <linux/atomic.h>
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#define pr_init(fmt, args...) ({ static const __initconst char __fmt[] = fmt; printk(__fmt, ## args); })
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/* See the Debug/Emulation chapter in the HRM */
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#define EMUDOF 0x00000001 /* EMUDAT_OUT full & valid */
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#define EMUDIF 0x00000002 /* EMUDAT_IN full & valid */
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#define EMUDOOVF 0x00000004 /* EMUDAT_OUT overflow */
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#define EMUDIOVF 0x00000008 /* EMUDAT_IN overflow */
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static inline uint32_t bfin_write_emudat(uint32_t emudat)
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{
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__asm__ __volatile__("emudat = %0;" : : "d"(emudat));
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return emudat;
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}
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static inline uint32_t bfin_read_emudat(void)
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{
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uint32_t emudat;
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__asm__ __volatile__("%0 = emudat;" : "=d"(emudat));
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return emudat;
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}
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static inline uint32_t bfin_write_emudat_chars(char a, char b, char c, char d)
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{
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return bfin_write_emudat((a << 0) | (b << 8) | (c << 16) | (d << 24));
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}
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#define CIRC_SIZE 2048 /* see comment in tty_io.c:do_tty_write() */
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#define CIRC_MASK (CIRC_SIZE - 1)
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#define circ_empty(circ) ((circ)->head == (circ)->tail)
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#define circ_free(circ) CIRC_SPACE((circ)->head, (circ)->tail, CIRC_SIZE)
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#define circ_cnt(circ) CIRC_CNT((circ)->head, (circ)->tail, CIRC_SIZE)
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#define circ_byte(circ, idx) ((circ)->buf[(idx) & CIRC_MASK])
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static struct tty_driver *bfin_jc_driver;
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static struct task_struct *bfin_jc_kthread;
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static struct tty_port port;
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static volatile struct circ_buf bfin_jc_write_buf;
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static int
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bfin_jc_emudat_manager(void *arg)
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{
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uint32_t inbound_len = 0, outbound_len = 0;
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while (!kthread_should_stop()) {
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struct tty_struct *tty = tty_port_tty_get(&port);
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/* no one left to give data to, so sleep */
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if (tty == NULL && circ_empty(&bfin_jc_write_buf)) {
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pr_debug("waiting for readers\n");
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__set_current_state(TASK_UNINTERRUPTIBLE);
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schedule();
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continue;
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}
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/* no data available, so just chill */
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if (!(bfin_read_DBGSTAT() & EMUDIF) && circ_empty(&bfin_jc_write_buf)) {
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pr_debug("waiting for data (in_len = %i) (circ: %i %i)\n",
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inbound_len, bfin_jc_write_buf.tail, bfin_jc_write_buf.head);
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tty_kref_put(tty);
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if (inbound_len)
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schedule();
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else
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schedule_timeout_interruptible(HZ);
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continue;
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}
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/* if incoming data is ready, eat it */
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if (bfin_read_DBGSTAT() & EMUDIF) {
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uint32_t emudat = bfin_read_emudat();
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if (inbound_len == 0) {
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pr_debug("incoming length: 0x%08x\n", emudat);
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inbound_len = emudat;
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} else {
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size_t num_chars = (4 <= inbound_len ? 4 : inbound_len);
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pr_debug(" incoming data: 0x%08x (pushing %zu)\n", emudat, num_chars);
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inbound_len -= num_chars;
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tty_insert_flip_string(&port, (unsigned char *)&emudat, num_chars);
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tty_flip_buffer_push(&port);
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}
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}
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/* if outgoing data is ready, post it */
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if (!(bfin_read_DBGSTAT() & EMUDOF) && !circ_empty(&bfin_jc_write_buf)) {
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if (outbound_len == 0) {
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outbound_len = circ_cnt(&bfin_jc_write_buf);
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bfin_write_emudat(outbound_len);
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pr_debug("outgoing length: 0x%08x\n", outbound_len);
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} else {
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int tail = bfin_jc_write_buf.tail;
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size_t ate = (4 <= outbound_len ? 4 : outbound_len);
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uint32_t emudat =
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bfin_write_emudat_chars(
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circ_byte(&bfin_jc_write_buf, tail + 0),
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circ_byte(&bfin_jc_write_buf, tail + 1),
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circ_byte(&bfin_jc_write_buf, tail + 2),
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circ_byte(&bfin_jc_write_buf, tail + 3)
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);
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bfin_jc_write_buf.tail += ate;
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outbound_len -= ate;
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if (tty)
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tty_wakeup(tty);
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pr_debug(" outgoing data: 0x%08x (pushing %zu)\n", emudat, ate);
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}
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}
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tty_kref_put(tty);
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}
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__set_current_state(TASK_RUNNING);
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return 0;
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}
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static int
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bfin_jc_open(struct tty_struct *tty, struct file *filp)
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{
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unsigned long flags;
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spin_lock_irqsave(&port.lock, flags);
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port.count++;
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spin_unlock_irqrestore(&port.lock, flags);
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tty_port_tty_set(&port, tty);
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wake_up_process(bfin_jc_kthread);
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return 0;
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}
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static void
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bfin_jc_close(struct tty_struct *tty, struct file *filp)
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{
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unsigned long flags;
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bool last;
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spin_lock_irqsave(&port.lock, flags);
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last = --port.count == 0;
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spin_unlock_irqrestore(&port.lock, flags);
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if (last)
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tty_port_tty_set(&port, NULL);
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wake_up_process(bfin_jc_kthread);
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}
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/* XXX: we dont handle the put_char() case where we must handle count = 1 */
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static int
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bfin_jc_circ_write(const unsigned char *buf, int count)
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{
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int i;
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count = min(count, circ_free(&bfin_jc_write_buf));
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pr_debug("going to write chunk of %i bytes\n", count);
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for (i = 0; i < count; ++i)
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circ_byte(&bfin_jc_write_buf, bfin_jc_write_buf.head + i) = buf[i];
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bfin_jc_write_buf.head += i;
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return i;
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}
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#ifndef CONFIG_BFIN_JTAG_COMM_CONSOLE
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# define console_lock()
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# define console_unlock()
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#endif
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static int
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bfin_jc_write(struct tty_struct *tty, const unsigned char *buf, int count)
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{
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int i;
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console_lock();
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i = bfin_jc_circ_write(buf, count);
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console_unlock();
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wake_up_process(bfin_jc_kthread);
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return i;
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}
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static void
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bfin_jc_flush_chars(struct tty_struct *tty)
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{
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wake_up_process(bfin_jc_kthread);
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}
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static int
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bfin_jc_write_room(struct tty_struct *tty)
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{
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return circ_free(&bfin_jc_write_buf);
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}
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static int
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bfin_jc_chars_in_buffer(struct tty_struct *tty)
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{
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return circ_cnt(&bfin_jc_write_buf);
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}
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static const struct tty_operations bfin_jc_ops = {
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.open = bfin_jc_open,
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.close = bfin_jc_close,
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.write = bfin_jc_write,
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/*.put_char = bfin_jc_put_char,*/
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.flush_chars = bfin_jc_flush_chars,
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.write_room = bfin_jc_write_room,
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.chars_in_buffer = bfin_jc_chars_in_buffer,
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};
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static int __init bfin_jc_init(void)
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{
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int ret;
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bfin_jc_kthread = kthread_create(bfin_jc_emudat_manager, NULL, DRV_NAME);
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if (IS_ERR(bfin_jc_kthread))
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return PTR_ERR(bfin_jc_kthread);
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ret = -ENOMEM;
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bfin_jc_write_buf.head = bfin_jc_write_buf.tail = 0;
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bfin_jc_write_buf.buf = kmalloc(CIRC_SIZE, GFP_KERNEL);
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if (!bfin_jc_write_buf.buf)
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goto err_buf;
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bfin_jc_driver = alloc_tty_driver(1);
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if (!bfin_jc_driver)
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goto err_driver;
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tty_port_init(&port);
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bfin_jc_driver->driver_name = DRV_NAME;
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bfin_jc_driver->name = DEV_NAME;
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bfin_jc_driver->type = TTY_DRIVER_TYPE_SERIAL;
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bfin_jc_driver->subtype = SERIAL_TYPE_NORMAL;
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bfin_jc_driver->init_termios = tty_std_termios;
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tty_set_operations(bfin_jc_driver, &bfin_jc_ops);
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tty_port_link_device(&port, bfin_jc_driver, 0);
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ret = tty_register_driver(bfin_jc_driver);
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if (ret)
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goto err;
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pr_init(KERN_INFO DRV_NAME ": initialized\n");
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return 0;
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err:
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tty_port_destroy(&port);
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put_tty_driver(bfin_jc_driver);
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err_driver:
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kfree(bfin_jc_write_buf.buf);
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err_buf:
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kthread_stop(bfin_jc_kthread);
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return ret;
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}
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module_init(bfin_jc_init);
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static void __exit bfin_jc_exit(void)
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{
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kthread_stop(bfin_jc_kthread);
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kfree(bfin_jc_write_buf.buf);
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tty_unregister_driver(bfin_jc_driver);
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put_tty_driver(bfin_jc_driver);
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tty_port_destroy(&port);
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}
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module_exit(bfin_jc_exit);
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#if defined(CONFIG_BFIN_JTAG_COMM_CONSOLE) || defined(CONFIG_EARLY_PRINTK)
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static void
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bfin_jc_straight_buffer_write(const char *buf, unsigned count)
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{
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unsigned ate = 0;
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while (bfin_read_DBGSTAT() & EMUDOF)
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continue;
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bfin_write_emudat(count);
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while (ate < count) {
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while (bfin_read_DBGSTAT() & EMUDOF)
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continue;
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bfin_write_emudat_chars(buf[ate], buf[ate+1], buf[ate+2], buf[ate+3]);
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ate += 4;
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}
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}
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#endif
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#ifdef CONFIG_BFIN_JTAG_COMM_CONSOLE
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static void
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bfin_jc_console_write(struct console *co, const char *buf, unsigned count)
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{
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if (bfin_jc_kthread == NULL)
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bfin_jc_straight_buffer_write(buf, count);
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else
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bfin_jc_circ_write(buf, count);
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}
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static struct tty_driver *
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bfin_jc_console_device(struct console *co, int *index)
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{
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*index = co->index;
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return bfin_jc_driver;
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}
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static struct console bfin_jc_console = {
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.name = DEV_NAME,
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.write = bfin_jc_console_write,
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.device = bfin_jc_console_device,
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.flags = CON_ANYTIME | CON_PRINTBUFFER,
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.index = -1,
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};
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static int __init bfin_jc_console_init(void)
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{
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register_console(&bfin_jc_console);
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return 0;
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}
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console_initcall(bfin_jc_console_init);
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#endif
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#ifdef CONFIG_EARLY_PRINTK
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static void __init
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bfin_jc_early_write(struct console *co, const char *buf, unsigned int count)
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{
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bfin_jc_straight_buffer_write(buf, count);
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}
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static struct console bfin_jc_early_console __initdata = {
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.name = "early_BFJC",
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.write = bfin_jc_early_write,
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.flags = CON_ANYTIME | CON_PRINTBUFFER,
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.index = -1,
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};
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struct console * __init
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bfin_jc_early_init(unsigned int port, unsigned int cflag)
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{
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return &bfin_jc_early_console;
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}
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#endif
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MODULE_AUTHOR("Mike Frysinger <vapier@gentoo.org>");
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MODULE_DESCRIPTION("TTY over Blackfin JTAG Communication");
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MODULE_LICENSE("GPL");
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