Author: avg
Date: Wed Oct 30 15:26:41 2019
New Revision: 354181
URL: https://svnweb.freebsd.org/changeset/base/354181
Log:
ow(4): protocol timings can now be changed as sysctl-s / tunables
I limited potentially infinite timings by 960 us based on a footnote on
page 38 of Maxim Integrated Application Note 937, Book of iButton
Standards: "In order not to mask interrupt signalling by other devices
on the 1–Wire bus, tRSTL + tR should always be less than 960 us."
MFC after: 3 weeks
Modified:
head/sys/dev/ow/ow.c
Modified: head/sys/dev/ow/ow.c
==============================================================================
--- head/sys/dev/ow/ow.c Wed Oct 30 15:15:53 2019 (r354180)
+++ head/sys/dev/ow/ow.c Wed Oct 30 15:26:41 2019 (r354181)
@@ -38,6 +38,7 @@ __FBSDID("$FreeBSD$");
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
+#include <sys/sysctl.h>
#include <dev/ow/ow.h>
#include <dev/ow/owll.h>
@@ -75,34 +76,137 @@ static void ow_release_bus(device_t ndev, device_t pde
static MALLOC_DEFINE(M_OW, "ow", "House keeping data for 1wire bus");
+static const struct ow_timing timing_regular_min = {
+ .t_slot = 60,
+ .t_low0 = 60,
+ .t_low1 = 1,
+ .t_release = 0,
+ .t_rec = 1,
+ .t_rdv = 15, /* fixed */
+ .t_rstl = 480,
+ .t_rsth = 480,
+ .t_pdl = 60,
+ .t_pdh = 15,
+ .t_lowr = 1,
+};
+
+static const struct ow_timing timing_regular_max = {
+ .t_slot = 120,
+ .t_low0 = 120,
+ .t_low1 = 15,
+ .t_release = 45,
+ .t_rec = 960, /* infinity */
+ .t_rdv = 15, /* fixed */
+ .t_rstl = 960, /* infinity */
+ .t_rsth = 960, /* infinity */
+ .t_pdl = 240, /* 60us to 240us */
+ .t_pdh = 60, /* 15us to 60us */
+ .t_lowr = 15, /* 1us */
+};
+
static struct ow_timing timing_regular = {
- .t_slot = 60, /* 60 to 120 */
- .t_low0 = 60, /* really 60 to 120 */
- .t_low1 = 1, /* really 1 to 15 */
- .t_release = 45, /* <= 45us */
- .t_rec = 15, /* at least 1us */
- .t_rdv = 15, /* 15us */
- .t_rstl = 480, /* 480us or more */
- .t_rsth = 480, /* 480us or more */
- .t_pdl = 60, /* 60us to 240us */
- .t_pdh = 60, /* 15us to 60us */
- .t_lowr = 1, /* 1us */
+ .t_slot = 60, /* 60 <= t < 120 */
+ .t_low0 = 60, /* 60 <= t < t_slot < 120 */
+ .t_low1 = 1, /* 1 <= t < 15 */
+ .t_release = 45, /* 0 <= t < 45 */
+ .t_rec = 15, /* 1 <= t < inf */
+ .t_rdv = 15, /* t == 15 */
+ .t_rstl = 480, /* 480 <= t < inf */
+ .t_rsth = 480, /* 480 <= t < inf */
+ .t_pdl = 60, /* 60 <= t < 240 */
+ .t_pdh = 60, /* 15 <= t < 60 */
+ .t_lowr = 1, /* 1 <= t < 15 */
};
/* NB: Untested */
+static const struct ow_timing timing_overdrive_min = {
+ .t_slot = 6,
+ .t_low0 = 6,
+ .t_low1 = 1,
+ .t_release = 0,
+ .t_rec = 1,
+ .t_rdv = 2, /* fixed */
+ .t_rstl = 48,
+ .t_rsth = 48,
+ .t_pdl = 8,
+ .t_pdh = 2,
+ .t_lowr = 1,
+};
+
+static const struct ow_timing timing_overdrive_max = {
+ .t_slot = 16,
+ .t_low0 = 16,
+ .t_low1 = 2,
+ .t_release = 4,
+ .t_rec = 960, /* infinity */
+ .t_rdv = 2, /* fixed */
+ .t_rstl = 80,
+ .t_rsth = 960, /* infinity */
+ .t_pdl = 24,
+ .t_pdh = 6,
+ .t_lowr = 2,
+};
+
static struct ow_timing timing_overdrive = {
- .t_slot = 11, /* 6us to 16us */
- .t_low0 = 6, /* really 6 to 16 */
- .t_low1 = 1, /* really 1 to 2 */
- .t_release = 4, /* <= 4us */
- .t_rec = 1, /* at least 1us */
- .t_rdv = 2, /* 2us */
- .t_rstl = 48, /* 48us to 80us */
- .t_rsth = 48, /* 48us or more */
- .t_pdl = 8, /* 8us to 24us */
- .t_pdh = 2, /* 2us to 6us */
- .t_lowr = 1, /* 1us */
+ .t_slot = 11, /* 6 <= t < 16 */
+ .t_low0 = 6, /* 6 <= t < t_slot < 16 */
+ .t_low1 = 1, /* 1 <= t < 2 */
+ .t_release = 4, /* 0 <= t < 4 */
+ .t_rec = 1, /* 1 <= t < inf */
+ .t_rdv = 2, /* t == 2 */
+ .t_rstl = 48, /* 48 <= t < 80 */
+ .t_rsth = 48, /* 48 <= t < inf */
+ .t_pdl = 8, /* 8 <= t < 24 */
+ .t_pdh = 2, /* 2 <= t < 6 */
+ .t_lowr = 1, /* 1 <= t < 2 */
};
+
+SYSCTL_DECL(_hw);
+SYSCTL_NODE(_hw, OID_AUTO, ow, CTLFLAG_RD, 0, "1-Wire protocol");
+SYSCTL_NODE(_hw_ow, OID_AUTO, regular, CTLFLAG_RD, 0,
+ "Regular mode timings");
+SYSCTL_NODE(_hw_ow, OID_AUTO, overdrive, CTLFLAG_RD, 0,
+ "Overdrive mode timings");
+
+#define _OW_TIMING_SYSCTL(mode, param) \
+ static int \
+ sysctl_ow_timing_ ## mode ## _ ## param(SYSCTL_HANDLER_ARGS) \
+ { \
+ int val = timing_ ## mode.param; \
+ int err; \
+ err = sysctl_handle_int(oidp, &val, 0, req); \
+ if (err != 0 || req->newptr == NULL) \
+ return (err); \
+ if (val < timing_ ## mode ## _min.param) \
+ return (EINVAL); \
+ else if (val >= timing_ ## mode ## _max.param) \
+ return (EINVAL); \
+ timing_ ## mode.param = val; \
+ return (0); \
+ } \
+SYSCTL_PROC(_hw_ow_ ## mode, OID_AUTO, param, \
+ CTLTYPE_INT | CTLFLAG_RWTUN, 0, sizeof(int), \
+ sysctl_ow_timing_ ## mode ## _ ## param, "I", \
+ "1-Wire timing parameter in microseconds (-1 resets to default)")
+
+#define OW_TIMING_SYSCTL(param) \
+ _OW_TIMING_SYSCTL(regular, param); \
+ _OW_TIMING_SYSCTL(overdrive, param)
+
+OW_TIMING_SYSCTL(t_slot);
+OW_TIMING_SYSCTL(t_low0);
+OW_TIMING_SYSCTL(t_low1);
+OW_TIMING_SYSCTL(t_release);
+OW_TIMING_SYSCTL(t_rec);
+OW_TIMING_SYSCTL(t_rdv);
+OW_TIMING_SYSCTL(t_rstl);
+OW_TIMING_SYSCTL(t_rsth);
+OW_TIMING_SYSCTL(t_pdl);
+OW_TIMING_SYSCTL(t_pdh);
+OW_TIMING_SYSCTL(t_lowr);
+
+#undef _OW_TIMING_SYSCTL
+#undef OW_TIMING_SYSCTL
static void
ow_send_byte(device_t lldev, struct ow_timing *t, uint8_t byte)
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