linux-kernel - [RESEND PATCH v3 6/9] tty: xuartps: Don't write IRQ disable register to enable interrupts

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <1396657425-31029-6-git-send-email-soren.brinkmann@xilinx.com>
Date:	Fri,  4 Apr 2014 17:23:42 -0700
From:	Soren Brinkmann <soren.brinkmann@...inx.com>
To:	Rob Herring <robh+dt@...nel.org>, Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Kumar Gala <galak@...eaurora.org>,
	Randy Dunlap <rdunlap@...radead.org>,
	Russell King <linux@....linux.org.uk>,
	Michal Simek <michal.simek@...inx.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Jiri Slaby <jslaby@...e.cz>,
	Grant Likely <grant.likely@...aro.org>
Cc:	Peter Crosthwaite <peter.crosthwaite@...inx.com>,
	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>,
	Soren Brinkmann <soren.brinkmann@...inx.com>,
	devicetree@...r.kernel.org, linux-doc@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	linux-serial@...r.kernel.org
Subject: [RESEND PATCH v3 6/9] tty: xuartps: Don't write IRQ disable register to enable interrupts

A comment states, that, according to the data sheet, to enable
interrupts the disable register should be written, but the enable
register could be left untouched. And it suspsects a HW bug requiring
to write both.
Reviewing the data sheet, these statements seem wrong. Just as one would
expect. Writing to the enable/disable register enables/disables
interrupts.
Hence the misleading comment and needless write to the disable register
are removed from the enable sequence.

Signed-off-by: Soren Brinkmann <soren.brinkmann@...inx.com>
Tested-by: Michal Simek <michal.simek@...inx.com>
---
I added a few lines to comment the change and altered the summary line.
In case this causes issues it should show up a little easier as a
candidate to revert.

Changes in v3: None
Changes in v2: None

---
 drivers/tty/serial/xilinx_uartps.c | 6 +-----
 1 file changed, 1 insertion(+), 5 deletions(-)

diff --git a/drivers/tty/serial/xilinx_uartps.c b/drivers/tty/serial/xilinx_uartps.c
index b182ab8cfd07..f9a2c2fc03c4 100644
--- a/drivers/tty/serial/xilinx_uartps.c
+++ b/drivers/tty/serial/xilinx_uartps.c
@@ -1085,11 +1085,7 @@ static void xuartps_console_write(struct console *co, const char *s,
 
 	xuartps_writel(ctrl, XUARTPS_CR_OFFSET);
 
-	/* restore interrupt state, it seems like there may be a h/w bug
-	 * in that the interrupt enable register should not need to be
-	 * written based on the data sheet
-	 */
-	xuartps_writel(~imr, XUARTPS_IDR_OFFSET);
+	/* restore interrupt state */
 	xuartps_writel(imr, XUARTPS_IER_OFFSET);
 
 	if (locked)
-- 
1.9.1.1.gbb9f595

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/