From b16b67689baa01a5616b651356df7ad3e47a8763 Mon Sep 17 00:00:00 2001 From: Finn Thain Date: Sun, 28 Jun 2020 14:23:12 +1000 Subject: [PATCH] macintosh/via-macii: Remove read_done state The driver state machine may enter the 'read_done' state when leaving the 'idle' or 'reading' state. This transition is pointless, as is the extra interrupt it requires. The interrupt is produced by the transceiver (even when it has no data to send) because an extra EVEN/ODD toggle was signalled by the driver. Drop the extra state to simplify the code. Fixes: 1da177e4c3f41 ("Linux-2.6.12-rc2") # v5.0+ Signed-off-by: Finn Thain Tested-by: Stan Johnson Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/0253194363af4426f9788796811a6a29fb87c713.1593318192.git.fthain@telegraphics.com.au --- drivers/macintosh/via-macii.c | 70 +++++++++++++++++-------------------------- 1 file changed, 28 insertions(+), 42 deletions(-) diff --git a/drivers/macintosh/via-macii.c b/drivers/macintosh/via-macii.c index 6a5cd7de05ba..d29c87943ca4 100644 --- a/drivers/macintosh/via-macii.c +++ b/drivers/macintosh/via-macii.c @@ -110,7 +110,6 @@ static enum macii_state { idle, sending, reading, - read_done, } macii_state; static struct adb_request *current_req; /* first request struct in the queue */ @@ -411,8 +410,8 @@ static irqreturn_t macii_interrupt(int irq, void *arg) reply_len = 1; } else { /* bus timeout */ - macii_state = read_done; reply_len = 0; + break; } /* set ADB state = even for first data byte */ @@ -471,20 +470,6 @@ static irqreturn_t macii_interrupt(int irq, void *arg) current_req = req->next; if (req->done) (*req->done)(req); - - if (!current_req) - macii_queue_poll(); - - if (current_req && macii_state == idle) - macii_start(); - - if (macii_state == idle) { - /* reset to shift in */ - via[ACR] &= ~SR_OUT; - x = via[SR]; - /* set ADB state idle - might get SRQ */ - via[B] = (via[B] & ~ST_MASK) | ST_IDLE; - } break; } } else { @@ -511,12 +496,28 @@ static irqreturn_t macii_interrupt(int irq, void *arg) } else if (status == ST_ODD && reply_len == 2) { srq_asserted = true; } else { - macii_state = read_done; + macii_state = idle; + + if (bus_timeout) + reply_len = 0; + + if (reading_reply) { + struct adb_request *req = current_req; + + req->reply_len = reply_len; + + req->complete = 1; + current_req = req->next; + if (req->done) + (*req->done)(req); + } else if (reply_len && autopoll_devs) { + adb_input(reply_buf, reply_len, 0); + } + break; } } - if (macii_state == reading && - reply_len < ARRAY_SIZE(reply_buf)) { + if (reply_len < ARRAY_SIZE(reply_buf)) { reply_ptr++; *reply_ptr = x; reply_len++; @@ -526,37 +527,22 @@ static irqreturn_t macii_interrupt(int irq, void *arg) via[B] ^= ST_MASK; break; - case read_done: - x = via[SR]; - - if (bus_timeout) - reply_len = 0; - - if (reading_reply) { - reading_reply = 0; - req = current_req; - req->reply_len = reply_len; - req->complete = 1; - current_req = req->next; - if (req->done) - (*req->done)(req); - } else if (reply_len && autopoll_devs) - adb_input(reply_buf, reply_len, 0); - - macii_state = idle; + default: + break; + } + if (macii_state == idle) { if (!current_req) macii_queue_poll(); if (current_req) macii_start(); - if (macii_state == idle) + if (macii_state == idle) { + via[ACR] &= ~SR_OUT; + x = via[SR]; via[B] = (via[B] & ~ST_MASK) | ST_IDLE; - break; - - default: - break; + } } local_irq_restore(flags); -- 2.11.0