The variables tracking allocated pages fragments in vchiq_arm.c
can be easily moved to struct vchiq_drv_mgmt instead of being global.
This helps us to drop the non-essential global variables in the vchiq
interface.
However, g_regs is intentionally kept global since it is read/write
in fast paths (for e.g. doorbell IRQs). Introducing it in struct
vchiq_drv_mgmt and getting it in remote_event_signal handler, turns
out to be quite tedious. Add a comment for the same.
Drop the TODO item as well, as it is now totally addressed:
> Get rid of all non essential global structures and create a proper per
device structure
No functional changes intended in this patch.
Signed-off-by: Umang Jain <umang.jain@xxxxxxxxxxxxxxxx>
---
drivers/staging/vc04_services/interface/TODO | 8 ---
.../interface/vchiq_arm/vchiq_arm.c | 57 +++++++++----------
.../interface/vchiq_arm/vchiq_arm.h | 6 ++
3 files changed, 34 insertions(+), 37 deletions(-)
diff --git a/drivers/staging/vc04_services/interface/TODO b/drivers/staging/vc04_services/interface/TODO
index 05eb5140d096..15f12b8f213e 100644
--- a/drivers/staging/vc04_services/interface/TODO
+++ b/drivers/staging/vc04_services/interface/TODO
@@ -41,14 +41,6 @@ The code follows the 80 characters limitation yet tends to go 3 or 4 levels of
indentation deep making it very unpleasant to read. This is specially relevant
in the character driver ioctl code and in the core thread functions.
-* Get rid of all non essential global structures and create a proper per
-device structure
-
-The first thing one generally sees in a probe function is a memory allocation
-for all the device specific data. This structure is then passed all over the
-driver. This is good practice since it makes the driver work regardless of the
-number of devices probed.
-
* Clean up Sparse warnings from __user annotations. See
vchiq_irq_queue_bulk_tx_rx(). Ensure that the address of "&waiter->bulk_waiter"
is never disclosed to userspace.
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
index ba096bcb32c8..c4807b302718 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.c
@@ -140,13 +140,11 @@ struct vchiq_pagelist_info {
unsigned int scatterlist_mapped;
};
+/*
+ * Essential global pointer since read/written on fast paths
+ * (doorbell IRQs).
+ */
static void __iomem *g_regs;
-static unsigned int g_fragments_size;
-static char *g_fragments_base;
-static char *g_free_fragments;
-static struct semaphore g_free_fragments_sema;
-
-static DEFINE_SEMAPHORE(g_free_fragments_mutex, 1);
static int
vchiq_blocking_bulk_transfer(struct vchiq_instance *instance, unsigned int handle, void *data,
@@ -377,20 +375,20 @@ create_pagelist(struct vchiq_instance *instance, char *buf, char __user *ubuf,
(drv_mgmt->pinfo->cache_line_size - 1)))) {
char *fragments;
- if (down_interruptible(&g_free_fragments_sema)) {
+ if (down_interruptible(&drv_mgmt->free_fragments_sema)) {
cleanup_pagelistinfo(instance, pagelistinfo);
return NULL;
}
- WARN_ON(!g_free_fragments);
+ WARN_ON(!drv_mgmt->free_fragments);
- down(&g_free_fragments_mutex);
- fragments = g_free_fragments;
+ down(&drv_mgmt->free_fragments_mutex);
+ fragments = drv_mgmt->free_fragments;
WARN_ON(!fragments);
- g_free_fragments = *(char **)g_free_fragments;
- up(&g_free_fragments_mutex);
+ drv_mgmt->free_fragments = *(char **)drv_mgmt->free_fragments;
+ up(&drv_mgmt->free_fragments_mutex);
pagelist->type = PAGELIST_READ_WITH_FRAGMENTS +
- (fragments - g_fragments_base) / g_fragments_size;
+ (fragments - drv_mgmt->fragments_base) / drv_mgmt->fragments_size;
}
return pagelistinfo;
@@ -420,10 +418,10 @@ free_pagelist(struct vchiq_instance *instance, struct vchiq_pagelist_info *pagel
pagelistinfo->scatterlist_mapped = 0;
/* Deal with any partial cache lines (fragments) */
- if (pagelist->type >= PAGELIST_READ_WITH_FRAGMENTS && g_fragments_base) {
- char *fragments = g_fragments_base +
+ if (pagelist->type >= PAGELIST_READ_WITH_FRAGMENTS && drv_mgmt->fragments_base) {
+ char *fragments = drv_mgmt->fragments_base +
(pagelist->type - PAGELIST_READ_WITH_FRAGMENTS) *
- g_fragments_size;
+ drv_mgmt->fragments_size;
int head_bytes, tail_bytes;
head_bytes = (drv_mgmt->pinfo->cache_line_size - pagelist->offset) &
@@ -448,11 +446,11 @@ free_pagelist(struct vchiq_instance *instance, struct vchiq_pagelist_info *pagel
fragments + drv_mgmt->pinfo->cache_line_size,
tail_bytes);
- down(&g_free_fragments_mutex);
- *(char **)fragments = g_free_fragments;
- g_free_fragments = fragments;
- up(&g_free_fragments_mutex);
- up(&g_free_fragments_sema);
+ down(&drv_mgmt->free_fragments_mutex);
+ *(char **)fragments = drv_mgmt->free_fragments;
+ drv_mgmt->free_fragments = fragments;
+ up(&drv_mgmt->free_fragments_mutex);
+ up(&drv_mgmt->free_fragments_sema);
}
/* Need to mark all the pages dirty. */
@@ -488,11 +486,11 @@ static int vchiq_platform_init(struct platform_device *pdev, struct vchiq_state
if (err < 0)
return err;
- g_fragments_size = 2 * drv_mgmt->pinfo->cache_line_size;
+ drv_mgmt->fragments_size = 2 * drv_mgmt->pinfo->cache_line_size;
/* Allocate space for the channels in coherent memory */
slot_mem_size = PAGE_ALIGN(TOTAL_SLOTS * VCHIQ_SLOT_SIZE);
- frag_mem_size = PAGE_ALIGN(g_fragments_size * MAX_FRAGMENTS);
+ frag_mem_size = PAGE_ALIGN(drv_mgmt->fragments_size * MAX_FRAGMENTS);
slot_mem = dmam_alloc_coherent(dev, slot_mem_size + frag_mem_size,
&slot_phys, GFP_KERNEL);
@@ -512,15 +510,16 @@ static int vchiq_platform_init(struct platform_device *pdev, struct vchiq_state
vchiq_slot_zero->platform_data[VCHIQ_PLATFORM_FRAGMENTS_COUNT_IDX] =
MAX_FRAGMENTS;
- g_fragments_base = (char *)slot_mem + slot_mem_size;
+ drv_mgmt->fragments_base = (char *)slot_mem + slot_mem_size;
- g_free_fragments = g_fragments_base;
+ drv_mgmt->free_fragments = drv_mgmt->fragments_base;
for (i = 0; i < (MAX_FRAGMENTS - 1); i++) {
- *(char **)&g_fragments_base[i * g_fragments_size] =
- &g_fragments_base[(i + 1) * g_fragments_size];
+ *(char **)&drv_mgmt->fragments_base[i * drv_mgmt->fragments_size] =
+ &drv_mgmt->fragments_base[(i + 1) * drv_mgmt->fragments_size];
}
- *(char **)&g_fragments_base[i * g_fragments_size] = NULL;
- sema_init(&g_free_fragments_sema, MAX_FRAGMENTS);
+ *(char **)&drv_mgmt->fragments_base[i * drv_mgmt->fragments_size] = NULL;
+ sema_init(&drv_mgmt->free_fragments_sema, MAX_FRAGMENTS);
+ sema_init(&drv_mgmt->free_fragments_mutex, 1);
err = vchiq_init_state(state, vchiq_slot_zero, dev);
if (err)
diff --git a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
index 1190fab2efc4..1134187da6ab 100644
--- a/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
+++ b/drivers/staging/vc04_services/interface/vchiq_arm/vchiq_arm.h
@@ -41,6 +41,12 @@ struct vchiq_drv_mgmt {
bool connected;
int num_deferred_callbacks;
void (*deferred_callback[VCHIQ_DRV_MAX_CALLBACKS])(void);
+
+ struct semaphore free_fragments_sema;
+ struct semaphore free_fragments_mutex;
+ char *fragments_base;
+ char *free_fragments;
+ unsigned int fragments_size;
};
struct user_service {
--
2.43.0
