| 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
| ||
|
Date: Tue, 14 Jul 2015 15:45:52 +0100
From: Nariman Poushin <nariman@...nsource.wolfsonmicro.com>
To: broonie@...nel.org
Cc: nariman@...nsource.wolfsonmicro.com, gregkh@...uxfoundation.org,
airlied@...ux.ie, dmitry.torokhov@...il.com, sameo@...ux.intel.com,
lee.jones@...aro.org, tony@...mide.com, lgirdwood@...il.com,
brian.austin@...rus.com, Paul.Handrigan@...rus.com,
support.opensource@...semi.com, bardliao@...ltek.com,
oder_chiou@...ltek.com, laurent.pinchart+renesas@...asonboard.com,
lars@...afoo.de, dmurphy@...com, linux-kernel@...r.kernel.org,
dri-devel@...ts.freedesktop.org,
patches@...nsource.wolfsonmicro.com, linux-omap@...r.kernel.org,
alsa-devel@...a-project.org, peter.ujfalusi@...com
Subject: [PATCH 2/2] V4 regmap: Apply optional delay in multi_reg_write/register_patch
We treat a delay in a sequence the same way we treat a page change as
they are logically similar in that you can coalesce all write before
a delay (in the same way you can coalesce all writes before a page
change is needed)
Signed-off-by: Nariman Poushin <nariman@...nsource.wolfsonmicro.com>
---
drivers/base/regmap/regmap.c | 65 ++++++++++++++++++++++++++++++++++++++++----
1 file changed, 59 insertions(+), 6 deletions(-)
diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 0a849ee..a67473c2 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -18,6 +18,7 @@
#include <linux/of.h>
#include <linux/rbtree.h>
#include <linux/sched.h>
+#include <linux/delay.h>
#define CREATE_TRACE_POINTS
#include "trace.h"
@@ -47,6 +48,17 @@ static int _regmap_bus_reg_write(void *context, unsigned int reg,
static int _regmap_bus_raw_write(void *context, unsigned int reg,
unsigned int val);
+static void regmap_sequence_delay(unsigned int delay_us)
+{
+ /* For small delays it isn't worth setting up the hrtimers
+ * so fall back on udelay
+ */
+ if (delay_us < 10)
+ udelay(delay_us);
+ else
+ usleep_range(delay_us, delay_us * 2);
+}
+
bool regmap_reg_in_ranges(unsigned int reg,
const struct regmap_range *ranges,
unsigned int nranges)
@@ -1819,10 +1831,12 @@ static int _regmap_range_multi_paged_reg_write(struct regmap *map,
int i, n;
struct reg_sequence *base;
unsigned int this_page = 0;
+ unsigned int page_change = 0;
/*
* the set of registers are not neccessarily in order, but
* since the order of write must be preserved this algorithm
- * chops the set each time the page changes
+ * chops the set each time the page changes. This also applies
+ * if there is a delay required at any point in the sequence.
*/
base = regs;
for (i = 0, n = 0; i < num_regs; i++, n++) {
@@ -1838,16 +1852,48 @@ static int _regmap_range_multi_paged_reg_write(struct regmap *map,
this_page = win_page;
if (win_page != this_page) {
this_page = win_page;
+ page_change = 1;
+ }
+ }
+
+ /* If we have both a page change and a delay make sure to
+ * write the regs and apply the delay before we change the
+ * page.
+ */
+
+ if (page_change || regs[i].delay_us) {
+
+ /* For situations where the first write requires
+ * a delay we need to make sure we don't call
+ * raw_multi_reg_write with n=0
+ * This can't occur with page breaks as we
+ * never write on the first iteration
+ */
+ if (regs[i].delay_us && i == 0)
+ n = 1;
+
ret = _regmap_raw_multi_reg_write(map, base, n);
if (ret != 0)
return ret;
+
+ if (regs[i].delay_us)
+ regmap_sequence_delay(regs[i].delay_us);
+
base += n;
n = 0;
- }
- ret = _regmap_select_page(map, &base[n].reg, range, 1);
- if (ret != 0)
- return ret;
+
+ if (page_change) {
+ ret = _regmap_select_page(map,
+ &base[n].reg,
+ range, 1);
+ if (ret != 0)
+ return ret;
+
+ page_change = 0;
+ }
+
}
+
}
if (n > 0)
return _regmap_raw_multi_reg_write(map, base, n);
@@ -1866,6 +1912,9 @@ static int _regmap_multi_reg_write(struct regmap *map,
ret = _regmap_write(map, regs[i].reg, regs[i].def);
if (ret != 0)
return ret;
+
+ if (regs[i].delay_us)
+ regmap_sequence_delay(regs[i].delay_us);
}
return 0;
}
@@ -1905,8 +1954,12 @@ static int _regmap_multi_reg_write(struct regmap *map,
for (i = 0; i < num_regs; i++) {
unsigned int reg = regs[i].reg;
struct regmap_range_node *range;
+
+ /* Coalesce all the writes between a page break or a delay
+ * in a sequence
+ */
range = _regmap_range_lookup(map, reg);
- if (range) {
+ if (range || regs[i].delay_us) {
size_t len = sizeof(struct reg_sequence)*num_regs;
struct reg_sequence *base = kmemdup(regs, len,
GFP_KERNEL);
--
2.1.4
--
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/
Powered by blists - more mailing lists