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authorNicholas Piggin <npiggin@gmail.com>2018-05-01 00:55:58 +1000
committerMichael Ellerman <mpe@ellerman.id.au>2018-08-20 20:19:54 +1000
commit95b861a76c1ded3e89d33a3d9f4552dce22e9875 (patch)
tree407243710c5ee124e906a36750246c30f6dc957b /arch
parent997dd26cb3c8b7c9b8765751cc1491ad33b2024f (diff)
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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: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch')
-rw-r--r--arch/powerpc/include/asm/opal.h1
-rw-r--r--arch/powerpc/platforms/powernv/opal.c83
2 files changed, 53 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,