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greybus: create host device cport id map 

A Greybus host device has a pool of CPort Ids it can use.  When we
establish a connection with a CPort on another module we will need
to allocate one from those that are available.

This patch adds a bitmap to the greybus host device structure that
allows cport ids to be allocated and freed as needed.

Signed-off-by: Alex Elder <elder@linaro.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
This commit is contained in:
Alex Elder 2014-10-02 12:30:03 -05:00 committed by Greg Kroah-Hartman
parent 63cc932b02
commit 1bb3c724e8
2 changed files with 93 additions and 0 deletions
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75
drivers/staging/greybus/core.c
View File

@ -30,6 +30,8 @@ int greybus_disabled(void)
}
EXPORT_SYMBOL_GPL(greybus_disabled);
static spinlock_t cport_id_map_lock;
static int greybus_module_match(struct device *dev, struct device_driver *drv)
{
struct greybus_driver *driver = to_greybus_driver(dev->driver);
@ -261,6 +263,69 @@ void greybus_remove_device(struct gb_module *gmod)
static DEFINE_MUTEX(hd_mutex);
/*
* Allocate an available CPort Id for use on the given host device.
* Returns the CPort Id, or CPORT_ID_BAD of none remain.
*
* The lowest-available id is returned, so the first call is
* guaranteed to allocate CPort Id 0.
*/
u16 greybus_hd_cport_id_alloc(struct greybus_host_device *hd)
{
unsigned long cport_id;
/* If none left, return BAD */
if (hd->cport_id_count == HOST_DEV_CPORT_ID_MAX)
return CPORT_ID_BAD;
spin_lock_irq(&cport_id_map_lock);
cport_id = find_next_zero_bit(hd->cport_id_map, hd->cport_id_count,
hd->cport_id_next_free);
if (cport_id < hd->cport_id_count) {
hd->cport_id_next_free = cport_id + 1; /* Success */
hd->cport_id_count++;
} else {
/* Lost a race for the last one */
if (hd->cport_id_count != HOST_DEV_CPORT_ID_MAX) {
pr_err("bad cport_id_count in alloc");
hd->cport_id_count = HOST_DEV_CPORT_ID_MAX;
}
cport_id = CPORT_ID_BAD;
}
spin_unlock_irq(&cport_id_map_lock);
return cport_id;
}
/*
* Free a previously-allocated CPort Id on the given host device.
*/
void greybus_hd_cport_id_free(struct greybus_host_device *hd, u16 cport_id)
{
if (cport_id >= HOST_DEV_CPORT_ID_MAX) {
pr_err("bad cport_id %hu\n", cport_id);
return;
}
if (!hd->cport_id_count) {
pr_err("too many cport_id frees\n");
return;
}
spin_lock_irq(&cport_id_map_lock);
if (test_and_clear_bit(cport_id, hd->cport_id_map)) {
if (hd->cport_id_count) {
hd->cport_id_count--;
if (cport_id < hd->cport_id_next_free)
hd->cport_id_next_free = cport_id;
} else {
pr_err("bad cport_id_count in free");
}
} else {
pr_err("duplicate cport_id %hu free\n", cport_id);
}
spin_unlock_irq(&cport_id_map_lock);
}
static void free_hd(struct kref *kref)
{
struct greybus_host_device *hd;
@ -284,6 +349,13 @@ struct greybus_host_device *greybus_create_hd(struct greybus_host_driver *driver
hd->driver = driver;
INIT_LIST_HEAD(&hd->modules);
/* Pre-allocate CPort 0 for control stuff. XXX */
if (greybus_hd_cport_id_alloc(hd) != 0) {
pr_err("couldn't allocate cport 0\n");
kfree(hd);
return NULL;
}
return hd;
}
EXPORT_SYMBOL_GPL(greybus_create_hd);
@ -299,6 +371,9 @@ static int __init gb_init(void)
{
int retval;
BUILD_BUG_ON(HOST_DEV_CPORT_ID_MAX >= (long)CPORT_ID_BAD);
spin_lock_init(&cport_id_map_lock);
retval = gb_debugfs_init();
if (retval) {
pr_err("debugfs failed\n");

18
drivers/staging/greybus/greybus.h
View File

@ -18,6 +18,7 @@
#include <linux/device.h>
#include <linux/module.h>
#include "kernel_ver.h"
#include "greybus_id.h"
#include "greybus_manifest.h"
#include "manifest.h"
@ -44,6 +45,15 @@
.match_flags = GREYBUS_DEVICE_ID_MATCH_SERIAL, \
.serial_number = (s),
/* XXX I couldn't get my Kconfig file to be noticed for out-of-tree build */
#ifndef CONFIG_HOST_DEV_CPORT_ID_MAX
#define CONFIG_HOST_DEV_CPORT_ID_MAX 128
#endif /* !CONFIG_HOST_DEV_CPORT_ID_MAX */
/* Maximum number of CPorts usable by a host device */
/* XXX This should really be determined by the AP module manifest */
#define HOST_DEV_CPORT_ID_MAX CONFIG_HOST_DEV_CPORT_ID_MAX
#define CPORT_ID_BAD U16_MAX /* UniPro max id is 4095 */
/*
gbuf
@ -185,10 +195,18 @@ struct greybus_host_device {
struct list_head modules;
struct list_head connections;
spinlock_t cport_id_map_lock;
DECLARE_BITMAP(cport_id_map, HOST_DEV_CPORT_ID_MAX);
u16 cport_id_count; /* How many have been allocated */
u16 cport_id_next_free; /* Where to start checking anyway */
/* Private data for the host driver */
unsigned long hd_priv[0] __attribute__ ((aligned(sizeof(s64))));
};
u16 greybus_hd_cport_id_alloc(struct greybus_host_device *hd);
void greybus_hd_cport_id_free(struct greybus_host_device *hd, u16 cport_id);
struct greybus_host_device *greybus_create_hd(struct greybus_host_driver *host_driver,
struct device *parent);
void greybus_remove_hd(struct greybus_host_device *hd);