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[src/thorpej-i2c-spi-conf]: src/sys/dev/i2c Rather than allocating 8KB (!!) o...
details: https://anonhg.NetBSD.org/src/rev/2c3720084be0
branches: thorpej-i2c-spi-conf
changeset: 1020813:2c3720084be0
user: thorpej <thorpej%NetBSD.org@localhost>
date: Sun May 16 04:40:08 2021 +0000
description:
Rather than allocating 8KB (!!) of space per i2c bus for a sparsely
populated array of child devices, use a sorted list instead, optimized
a bit for the common usage pattern.
diffstat:
sys/dev/i2c/i2c.c | 271 +++++++++++++++++++++++++++++++++++++++++++++++------
1 files changed, 238 insertions(+), 33 deletions(-)
diffs (truncated from 378 to 300 lines):
diff -r bf2af593633d -r 2c3720084be0 sys/dev/i2c/i2c.c
--- a/sys/dev/i2c/i2c.c Sat May 15 21:19:46 2021 +0000
+++ b/sys/dev/i2c/i2c.c Sun May 16 04:40:08 2021 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: i2c.c,v 1.78.2.2 2021/05/08 11:34:38 thorpej Exp $ */
+/* $NetBSD: i2c.c,v 1.78.2.3 2021/05/16 04:40:08 thorpej Exp $ */
/*-
* Copyright (c) 2021 The NetBSD Foundation, Inc.
@@ -69,7 +69,7 @@
#endif
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: i2c.c,v 1.78.2.2 2021/05/08 11:34:38 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: i2c.c,v 1.78.2.3 2021/05/16 04:40:08 thorpej Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -95,10 +95,20 @@
#define I2C_MAX_ADDR 0x3ff /* 10-bit address, max */
#endif
+struct i2c_device_link {
+ TAILQ_ENTRY(i2c_device_link) l_list;
+ device_t l_device;
+ i2c_addr_t l_addr;
+};
+
+TAILQ_HEAD(i2c_devlist_head, i2c_device_link);
+
struct iic_softc {
device_t sc_dev;
i2c_tag_t sc_tag;
- device_t sc_devices[I2C_MAX_ADDR + 1];
+
+ kmutex_t sc_devlist_lock;
+ struct i2c_devlist_head sc_devlist;
};
static dev_type_open(iic_open);
@@ -129,6 +139,179 @@
static void iic_smbus_intr_thread(void *);
+static struct i2c_device_link *
+iic_devslot_lookup(struct iic_softc *sc, i2c_addr_t addr)
+{
+ struct i2c_device_link *link;
+
+ KASSERT(mutex_owned(&sc->sc_devlist_lock));
+
+ /*
+ * A common pattern is "reserve then insert or delete", and
+ * this is often done in increasing address order. So check
+ * if the last entry is the one we're looking for before we
+ * search the list from the front.
+ */
+ link = TAILQ_LAST(&sc->sc_devlist, i2c_devlist_head);
+ if (link == NULL) {
+ /* List is empty. */
+ return NULL;
+ }
+ if (link->l_addr == addr) {
+ return link;
+ }
+
+ TAILQ_FOREACH(link, &sc->sc_devlist, l_list) {
+ /*
+ * The list is sorted, so if the current list element
+ * has an address larger than the one we're looking
+ * for, then it's not in the list.
+ */
+ if (link->l_addr > addr) {
+ break;
+ }
+ if (link->l_addr == addr) {
+ return link;
+ }
+ }
+ return NULL;
+}
+
+static bool
+iic_devslot_reserve(struct iic_softc *sc, i2c_addr_t addr)
+{
+ struct i2c_device_link *link, *new_link;
+
+ new_link = kmem_zalloc(sizeof(*new_link), KM_SLEEP);
+ new_link->l_addr = addr;
+
+ mutex_enter(&sc->sc_devlist_lock);
+
+ /* Optimize for reserving in increasing i2c address order. */
+ link = TAILQ_LAST(&sc->sc_devlist, i2c_devlist_head);
+ if (link == NULL || link->l_addr < new_link->l_addr) {
+ TAILQ_INSERT_TAIL(&sc->sc_devlist, new_link, l_list);
+ new_link = NULL;
+ goto done;
+ }
+ KASSERT(!TAILQ_EMPTY(&sc->sc_devlist));
+
+ /* Sort the new entry into the list. */
+ TAILQ_FOREACH(link, &sc->sc_devlist, l_list) {
+ if (link->l_addr < new_link->l_addr) {
+ continue;
+ }
+ if (link->l_addr == new_link->l_addr) {
+ /* Address is already reserved / in-use. */
+ goto done;
+ }
+ /*
+ * If we get here, we know we should be inserted
+ * before this element, because we checked to see
+ * if we should be the last entry before entering
+ * the loop.
+ */
+ KASSERT(link->l_addr > new_link->l_addr);
+ TAILQ_INSERT_BEFORE(link, new_link, l_list);
+ new_link = NULL;
+ break;
+ }
+ /*
+ * Because we checked for an empty list early, if we got
+ * here it means we inserted before "link".
+ */
+ KASSERT(link != NULL);
+ KASSERT(TAILQ_NEXT(new_link, l_list) == link);
+
+ done:
+ mutex_exit(&sc->sc_devlist_lock);
+
+ if (new_link != NULL) {
+ kmem_free(new_link, sizeof(*new_link));
+ return false;
+ }
+ return true;
+}
+
+static bool
+iic_devslot_insert(struct iic_softc *sc, device_t dev, i2c_addr_t addr)
+{
+ struct i2c_device_link *link;
+ bool rv = false;
+
+ mutex_enter(&sc->sc_devlist_lock);
+
+ link = iic_devslot_lookup(sc, addr);
+ if (link != NULL) {
+ if (link->l_device == NULL) {
+ link->l_device = dev;
+ rv = true;
+ }
+ }
+
+ mutex_exit(&sc->sc_devlist_lock);
+
+ return rv;
+}
+
+static bool
+iic_devslot_remove(struct iic_softc *sc, device_t dev, i2c_addr_t addr)
+{
+ struct i2c_device_link *link;
+ bool rv = false;
+
+ mutex_enter(&sc->sc_devlist_lock);
+
+ link = iic_devslot_lookup(sc, addr);
+ if (link != NULL) {
+ if (link->l_device == dev) {
+ TAILQ_REMOVE(&sc->sc_devlist, link, l_list);
+ rv = true;
+ } else {
+ link = NULL;
+ }
+ }
+
+ mutex_exit(&sc->sc_devlist_lock);
+
+ if (link != NULL) {
+ kmem_free(link, sizeof(*link));
+ return false;
+ }
+ return rv;
+}
+
+static bool
+iic_devslot_set(struct iic_softc *sc, device_t dev, i2c_addr_t addr)
+{
+ return dev != NULL ? iic_devslot_insert(sc, dev, addr)
+ : iic_devslot_remove(sc, dev, addr);
+}
+
+static bool
+iic_devslot_lookup_addr(struct iic_softc *sc, device_t dev, i2c_addr_t *addrp)
+{
+ struct i2c_device_link *link;
+ bool rv = false;
+
+ KASSERT(dev != NULL);
+ KASSERT(addrp != NULL);
+
+ mutex_enter(&sc->sc_devlist_lock);
+
+ TAILQ_FOREACH(link, &sc->sc_devlist, l_list) {
+ if (link->l_device == dev) {
+ *addrp = link->l_addr;
+ rv = true;
+ break;
+ }
+ }
+
+ mutex_exit(&sc->sc_devlist_lock);
+
+ return rv;
+}
+
static int
iic_print_direct(void *aux, const char *pnp)
{
@@ -346,6 +529,8 @@
for (ia.ia_addr = first_addr; ia.ia_addr <= last_addr; ia.ia_addr++) {
int error, match_result;
+ device_t newdev;
+ bool rv __diagused;
/*
* Skip I2C addresses that are reserved for
@@ -357,7 +542,7 @@
/*
* Skip addresses where a device is already attached.
*/
- if (sc->sc_devices[ia.ia_addr] != NULL)
+ if (! iic_devslot_reserve(sc, ia.ia_addr))
continue;
/*
@@ -374,8 +559,11 @@
* is there.
*/
match_result = config_probe(parent, cf, &ia);/*XXX*/
- if (match_result <= 0)
+ if (match_result <= 0) {
+ rv = iic_devslot_remove(sc, NULL, ia.ia_addr);
+ KASSERT(rv);
continue;
+ }
/*
* If the quality of the match by the driver was low
@@ -384,11 +572,15 @@
* to see if it looks like something is really there.
*/
if (match_result == I2C_MATCH_ADDRESS_ONLY &&
- (error = (*probe_func)(sc, &ia, 0)) != 0)
+ (error = (*probe_func)(sc, &ia, 0)) != 0) {
+ rv = iic_devslot_remove(sc, NULL, ia.ia_addr);
+ KASSERT(rv);
continue;
+ }
- sc->sc_devices[ia.ia_addr] =
- config_attach(parent, cf, &ia, iic_print, CFARG_EOL);
+ newdev = config_attach(parent, cf, &ia, iic_print, CFARG_EOL);
+ rv = iic_devslot_set(sc, newdev, ia.ia_addr);
+ KASSERT(rv);
}
return 0;
@@ -398,13 +590,15 @@
iic_child_detach(device_t parent, device_t child)
{
struct iic_softc *sc = device_private(parent);
- int i;
+ i2c_addr_t addr;
+ bool rv __diagused;
- for (i = 0; i <= I2C_MAX_ADDR; i++)
- if (sc->sc_devices[i] == child) {
- sc->sc_devices[i] = NULL;
- break;
- }
+ if (! iic_devslot_lookup_addr(sc, child, &addr)) {
+ return;
+ }
+
+ rv = iic_devslot_remove(sc, child, addr);
+ KASSERT(rv);
}
static int
@@ -423,6 +617,8 @@
{
struct iic_softc *sc = device_private(self);
int loc[IICCF_NLOCS] = { 0 };
+ device_t newdev;
+ bool rv __diagused;
args->count++;
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