From: Emilio G. Cota <[email protected]> In a configuration with several bridges, each bridge is assigned a certain bus number depending on the order in which vme_register_bridge is called. This can complicate multi-bridge installations because the eventual bus numbers will depend on the order the bridges were loaded.
The appended allows bridges to register with a bus number of their choice, while keeping the previous 'first come, first served' behaviour as the default. Signed-off-by: Emilio G. Cota <[email protected]> --- drivers/staging/vme/bridges/vme_ca91cx42.c | 1 + drivers/staging/vme/bridges/vme_tsi148.c | 1 + drivers/staging/vme/vme.c | 46 +++++++++++++++++++++------- drivers/staging/vme/vme.h | 1 + 4 files changed, 38 insertions(+), 11 deletions(-) diff --git a/drivers/staging/vme/bridges/vme_ca91cx42.c b/drivers/staging/vme/bridges/vme_ca91cx42.c index 1f2089f..14e10a6 100644 --- a/drivers/staging/vme/bridges/vme_ca91cx42.c +++ b/drivers/staging/vme/bridges/vme_ca91cx42.c @@ -1600,6 +1600,7 @@ static int ca91cx42_probe(struct pci_dev *pdev, const struct pci_device_id *id) } ca91cx42_bridge->driver_priv = ca91cx42_device; + ca91cx42_bridge->num = -1; /* Enable the device */ retval = pci_enable_device(pdev); diff --git a/drivers/staging/vme/bridges/vme_tsi148.c b/drivers/staging/vme/bridges/vme_tsi148.c index 1cba1fa..e341122 100644 --- a/drivers/staging/vme/bridges/vme_tsi148.c +++ b/drivers/staging/vme/bridges/vme_tsi148.c @@ -2247,6 +2247,7 @@ static int tsi148_probe(struct pci_dev *pdev, const struct pci_device_id *id) } tsi148_bridge->driver_priv = tsi148_device; + tsi148_bridge->num = -1; /* Enable the device */ retval = pci_enable_device(pdev); diff --git a/drivers/staging/vme/vme.c b/drivers/staging/vme/vme.c index 47e9d5c..9fa0609 100644 --- a/drivers/staging/vme/vme.c +++ b/drivers/staging/vme/vme.c @@ -1307,20 +1307,42 @@ EXPORT_SYMBOL(vme_slot_get); /* - Bridge Registration --------------------------------------------------- */ -static int vme_alloc_bus_num(void) +/* call with vme_bus_num_mtx held */ +static int __vme_alloc_bus_num(int *bus) { - int i; - - mutex_lock(&vme_bus_num_mtx); - for (i = 0; i < sizeof(vme_bus_numbers) * 8; i++) { - if (((vme_bus_numbers >> i) & 0x1) == 0) { - vme_bus_numbers |= (0x1 << i); - break; + int index; + + if (*bus == -1) { + /* try to find a free bus number */ + for (index = 0; index < VME_MAX_BRIDGES; index++) { + if (~vme_bus_numbers & 1 << index) { + *bus = index; + break; + } + } + if (index == VME_MAX_BRIDGES) { + pr_warn("vme: No bus numbers left\n"); + return -ENODEV; + } + } else { + /* check if the given bus number is already in use */ + if (vme_bus_numbers & (1 << *bus)) { + pr_warn("vme: bus number %d already in use\n", *bus); + return -EBUSY; } } - mutex_unlock(&vme_bus_num_mtx); + vme_bus_numbers |= 1 << *bus; + return 0; +} + +static int vme_alloc_bus_num(int *bus) +{ + int ret; - return i; + mutex_lock(&vme_bus_num_mtx); + ret = __vme_alloc_bus_num(bus); + mutex_unlock(&vme_bus_num_mtx); + return ret; } static void vme_free_bus_num(int bus) @@ -1336,7 +1358,9 @@ int vme_register_bridge(struct vme_bridge *bridge) int retval; int i; - bridge->num = vme_alloc_bus_num(); + retval = vme_alloc_bus_num(&bridge->num); + if (retval) + return retval; /* This creates 32 vme "slot" devices. This equates to a slot for each * ID available in a system conforming to the ANSI/VITA 1-1994 diff --git a/drivers/staging/vme/vme.h b/drivers/staging/vme/vme.h index 48768ca..5cdfa52 100644 --- a/drivers/staging/vme/vme.h +++ b/drivers/staging/vme/vme.h @@ -88,6 +88,7 @@ struct vme_resource { extern struct bus_type vme_bus_type; +#define VME_MAX_BRIDGES 32 #define VME_SLOT_CURRENT -1 #define VME_SLOT_ALL -2 -- 1.7.1 _______________________________________________ devel mailing list [email protected] http://driverdev.linuxdriverproject.org/mailman/listinfo/devel
