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Commit 95b861a7 authored by Nicholas Piggin's avatar Nicholas Piggin Committed by Michael Ellerman
Browse files

powerpc/powernv: provide a console flush operation for opal hvc driver 



Provide the flush hv_op for the opal hvc driver. This will flush the
firmware console buffers without spinning with interrupts disabled.

Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 997dd26c

arch/powerpc/include/asm/opal.h

+1 −0
Original line number Diff line number Diff line
@@ -308,6 +308,7 @@ extern void opal_configure_cores(void); 
extern int opal_get_chars(uint32_t vtermno, char *buf, int count);

extern int opal_put_chars(uint32_t vtermno, const char *buf, int total_len);

extern int opal_put_chars_atomic(uint32_t vtermno, const char *buf, int total_len);

extern int opal_flush_chars(uint32_t vtermno, bool wait);

extern int opal_flush_console(uint32_t vtermno);



extern void hvc_opal_init_early(void);

arch/powerpc/platforms/powernv/opal.c

+52 −31
Original line number Diff line number Diff line
@@ -370,12 +370,8 @@ static int __opal_put_chars(uint32_t vtermno, const char *data, int total_len, b 
	olen = cpu_to_be64(total_len);

	rc = opal_console_write(vtermno, &olen, data);

	if (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {

		if (rc == OPAL_BUSY_EVENT) {

			mdelay(OPAL_BUSY_DELAY_MS);

		if (rc == OPAL_BUSY_EVENT)

			opal_poll_events(NULL);

		} else if (rc == OPAL_BUSY_EVENT) {

			mdelay(OPAL_BUSY_DELAY_MS);

		}

		written = -EAGAIN;

		goto out;

	}
@@ -401,15 +397,6 @@ static int __opal_put_chars(uint32_t vtermno, const char *data, int total_len, b 
	if (atomic)

		spin_unlock_irqrestore(&opal_write_lock, flags);



	/* In the -EAGAIN case, callers loop, so we have to flush the console

	 * here in case they have interrupts off (and we don't want to wait

	 * for async flushing if we can make immediate progress here). If

	 * necessary the API could be made entirely non-flushing if the

	 * callers had a ->flush API to use.

	 */

	if (written == -EAGAIN)

		opal_flush_console(vtermno);



	return written;

}
@@ -429,41 +416,75 @@ int opal_put_chars_atomic(uint32_t vtermno, const char *data, int total_len) 
	return __opal_put_chars(vtermno, data, total_len, true);

}



int opal_flush_console(uint32_t vtermno)

static s64 __opal_flush_console(uint32_t vtermno)

{

	s64 rc;



	if (!opal_check_token(OPAL_CONSOLE_FLUSH)) {

		__be64 evt;



		WARN_ONCE(1, "opal: OPAL_CONSOLE_FLUSH missing.\n");

		/*

		 * If OPAL_CONSOLE_FLUSH is not implemented in the firmware,

		 * the console can still be flushed by calling the polling

		 * function while it has OPAL_EVENT_CONSOLE_OUTPUT events.

		 */

		do {

			opal_poll_events(&evt);

		} while (be64_to_cpu(evt) & OPAL_EVENT_CONSOLE_OUTPUT);

		WARN_ONCE(1, "opal: OPAL_CONSOLE_FLUSH missing.\n");



		opal_poll_events(&evt);

		if (!(be64_to_cpu(evt) & OPAL_EVENT_CONSOLE_OUTPUT))

			return OPAL_SUCCESS;

	}

		return OPAL_BUSY;



	do  {

		rc = OPAL_BUSY;

		while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) {

	} else {

		rc = opal_console_flush(vtermno);

		if (rc == OPAL_BUSY_EVENT) {

				mdelay(OPAL_BUSY_DELAY_MS);

			opal_poll_events(NULL);

			} else if (rc == OPAL_BUSY) {

				mdelay(OPAL_BUSY_DELAY_MS);

			rc = OPAL_BUSY;

		}

		return rc;

	}



}



/*

 * opal_flush_console spins until the console is flushed

 */

int opal_flush_console(uint32_t vtermno)

{

	for (;;) {

		s64 rc = __opal_flush_console(vtermno);



		if (rc == OPAL_BUSY || rc == OPAL_PARTIAL) {

			mdelay(1);

			continue;

		}

	} while (rc == OPAL_PARTIAL); /* More to flush */



		return opal_error_code(rc);

	}

}



/*

 * opal_flush_chars is an hvc interface that sleeps until the console is

 * flushed if wait, otherwise it will return -EBUSY if the console has data,

 * -EAGAIN if it has data and some of it was flushed.

 */

int opal_flush_chars(uint32_t vtermno, bool wait)

{

	for (;;) {

		s64 rc = __opal_flush_console(vtermno);



		if (rc == OPAL_BUSY || rc == OPAL_PARTIAL) {

			if (wait) {

				msleep(OPAL_BUSY_DELAY_MS);

				continue;

			}

			if (rc == OPAL_PARTIAL)

				return -EAGAIN;

		}



		return opal_error_code(rc);

	}

}



static int opal_recover_mce(struct pt_regs *regs,

					struct machine_check_event *evt)

drivers/tty/hvc/hvc_opal.c

+2 −0
Original line number Diff line number Diff line
@@ -52,6 +52,7 @@ static u32 hvc_opal_boot_termno; 
static const struct hv_ops hvc_opal_raw_ops = {

	.get_chars = opal_get_chars,

	.put_chars = opal_put_chars,

	.flush = opal_flush_chars,

	.notifier_add = notifier_add_irq,

	.notifier_del = notifier_del_irq,

	.notifier_hangup = notifier_hangup_irq,
@@ -141,6 +142,7 @@ static int hvc_opal_hvsi_tiocmset(struct hvc_struct *hp, unsigned int set, 
static const struct hv_ops hvc_opal_hvsi_ops = {

	.get_chars = hvc_opal_hvsi_get_chars,

	.put_chars = hvc_opal_hvsi_put_chars,

	.flush = opal_flush_chars,

	.notifier_add = hvc_opal_hvsi_open,

	.notifier_del = hvc_opal_hvsi_close,

	.notifier_hangup = hvc_opal_hvsi_hangup,