From 95b861a76c1ded3e89d33a3d9f4552dce22e9875 Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Tue, 1 May 2018 00:55:58 +1000 Subject: 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 Cc: linuxppc-dev@lists.ozlabs.org Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/include/asm/opal.h | 1 + arch/powerpc/platforms/powernv/opal.c | 83 ++++++++++++++++++++++------------- drivers/tty/hvc/hvc_opal.c | 2 + 3 files changed, 55 insertions(+), 31 deletions(-) diff --git a/arch/powerpc/include/asm/opal.h b/arch/powerpc/include/asm/opal.h index 834e7e29f1e4..ff3866473afe 100644 --- a/arch/powerpc/include/asm/opal.h +++ b/arch/powerpc/include/asm/opal.h @@ -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); diff --git a/arch/powerpc/platforms/powernv/opal.c b/arch/powerpc/platforms/powernv/opal.c index 404c379db168..38fe4087484a 100644 --- a/arch/powerpc/platforms/powernv/opal.c +++ b/arch/powerpc/platforms/powernv/opal.c @@ -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 @@ out: 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; } @@ -429,40 +416,74 @@ 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; - return OPAL_SUCCESS; + } else { + rc = opal_console_flush(vtermno); + if (rc == OPAL_BUSY_EVENT) { + opal_poll_events(NULL); + rc = OPAL_BUSY; + } + return rc; } - do { - rc = OPAL_BUSY; - while (rc == OPAL_BUSY || rc == OPAL_BUSY_EVENT) { - 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); +} + +/* + * 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; + } + + 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; } - } while (rc == OPAL_PARTIAL); /* More to flush */ - return opal_error_code(rc); + return opal_error_code(rc); + } } static int opal_recover_mce(struct pt_regs *regs, diff --git a/drivers/tty/hvc/hvc_opal.c b/drivers/tty/hvc/hvc_opal.c index f631f8bee308..77baf895108f 100644 --- a/drivers/tty/hvc/hvc_opal.c +++ b/drivers/tty/hvc/hvc_opal.c @@ -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, -- cgit v1.2.3