msm: kgsl: Fix several possible problem spots in the dispatcher

Fix a few spots that the compiler warnings missed. Avoid
dereferencing a pointer that may have returned ERR_PTR() without
first checking to see that if it did return ERR_PTR() and correct
an egregious signed / unsigned mixup. Not sure why the compiler
didn't yell at me for that one.

Change-Id: Ic0dedbadf075b34e51a89ce625d2308c5171a58d
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
gpu: msm: caf kk_3.5_rb1.15 updates
msm: kgsl: Restrict the maximum memory entries for bulk cache sync

Restrict the maximum number of memory entries that can be specified
to a single bulk cache sync call to PAGE_SIZE / sizeof(unsigned int)
so that the allocation can always fit within one page.

CRs-fixed: 578062
Change-Id: Ic0dedbad07e1986cd6ccc5b260ffef82b5adb6d3
Signed-off-by: Jordan Crouse <jcrouse@codeaurora.org>
msm: kgsl: Don't enable VBIF counters for targets that don't use them

Only targets with separate bus control need the VBIF counters enabled
by default.

Change-Id: I3a7fcedebf7a7cc80bc1bec5a7fd298b49b9b165
Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>
msm: kgsl: Prevent device start after it is already started

Check if device is already started in high priority workqueue thread,
this check prevents calling device start after it is already started,
thereby avoiding unpredictable behavior.

Change-Id: Iffcd065f8c02746d168c8e5779d10d4b0e2404a9
Signed-off-by: Tarun Karra <tkarra@codeaurora.org>
msm: kgsl: avoid zero length scatterlist allocation

During sglist allocation we calculate sglen as
per below

sglen_alloc = PAGE_ALIGN(size) >> PAGE_SHIFT;

sglen_alloc can be zero if size falls within the
last page. For example, when size = 0xFFFF_FF7B,
PAGE_ALIGN(0xFFFF_FF7B) will be 0, considering
0x1000 (4kb) PAGE_SIZE. if kzalloc() with
zero size, it will return ZERO_SIZE_PTR which is
not NULL and we always do NULL check. Dereferencing
ZERO_SIZE_PTR will lead to a distinct access fault.

Conflicts:
	drivers/gpu/msm/kgsl_sharedmem.h

Change-Id: Ibcc6198438c13b5111be0faa736328db92511597
CRs-Fixed: 563106
Signed-off-by: Prakash Kamliya <pkamliya@codeaurora.org>