[PATCHv3 1/2] Introduce intel_bug_present function.

Matwey V. Kornilov
2014-07-07T07:01:34Z

>From c89138e2c968c07dd11b3c6bfc05a803d0c5434d Mon Sep 17 00:00:00 2001
From: "Matwey V. Kornilov" <matwey.kornilov@gmail.com>
Date: Wed, 25 Jun 2014 00:53:54 +0400
Subject: [PATCHv3 1/2] Introduce intel_bug_present function.

Put the code to check present of the Intel bug from parport_EPP_supported
into new intel_bug_present function. The later also return ECR register
to the state it has before function call.

Tested-by: Heiko Andreas Sommer <hsommer@eso.org>
Signed-off-by: Matwey V. Kornilov <matwey@sai.msu.ru>
---
drivers/parport/parport_pc.c | 38 ++++++++++++++++++++++++++------------
1 file changed, 26 insertions(+), 12 deletions(-)

diff --git a/drivers/parport/parport_pc.c b/drivers/parport/parport_pc.c
index 76ee775..a6eaafb 100644
--- a/drivers/parport/parport_pc.c
+++ b/drivers/parport/parport_pc.c
@@ -1702,6 +1702,30 @@ static int parport_ECP_supported(struct parport *pb)
}
#endif

+static int intel_bug_present(struct parport *pb)
+{
+ const struct parport_pc_private *priv = pb->private_data;
+ int bug_present = 0;
+
+ if (priv->ecr) {
+ /* store value of ECR */
+ unsigned char ecr = inb(ECONTROL(pb));
+ unsigned char i;
+ for (i = 0x00; i < 0x80; i += 0x20) {
+ ECR_WRITE(pb, i);
+ if (clear_epp_timeout(pb)) {
+ /* Phony EPP in ECP. */
+ bug_present = 1;
+ break;
+ }
+ }
+ /* return ECR into the inital state */
+ ECR_WRITE(pb, ecr);
+ }
+
+ return bug_present;
+}
+
static int parport_ECPPS2_supported(struct parport *pb)
{
const struct parport_pc_private *priv = pb->private_data;
@@ -1722,8 +1746,6 @@ static int parport_ECPPS2_supported(struct parport *pb)

static int parport_EPP_supported(struct parport *pb)
{
- const struct parport_pc_private *priv = pb->private_data;
-
/*
* Theory:
* Bit 0 of STR is the EPP timeout bit, this bit is 0
@@ -1742,16 +1764,8 @@ static int parport_EPP_supported(struct parport *pb)
return 0; /* No way to clear timeout */

/* Check for Intel bug. */
- if (priv->ecr) {
- unsigned char i;
- for (i = 0x00; i < 0x80; i += 0x20) {
- ECR_WRITE(pb, i);
- if (clear_epp_timeout(pb)) {
- /* Phony EPP in ECP. */
- return 0;
- }
- }
- }
+ if (intel_bug_present(pb))
+ return 0;

pb->modes |= PARPORT_MODE_EPP;

--
1.8.1.4