amdkfd: Add basic modules to amdkfd

This patch adds the process module and three helper modules:

- kfd_process, which handles process which open /dev/kfd

- kfd_doorbell, which provides helper functions for doorbell allocation,
  release and mapping to userspace

- kfd_pasid, which provides helper functions for pasid allocation and release

- kfd_aperture, which provides helper functions for managing the LDS, Local GPU
  memory and Scratch memory apertures of the process

This patch only contains the basic kfd_process module, which doesn't contain
the reference to the queue scheduler. This was done to allow easier code review.

Also, this patch doesn't contain the calls to the IOMMU driver for binding the
pasid to the device. Again, this was done to allow easier code review

The kfd_process object is created when a process opens /dev/kfd and is closed
when the mm_struct of that process is teared-down.

v3:

Removed kfd_vidmem.c file
Replaced direct mmput call to mmu_notifier release
Removed typedefs
Moved bool field to end of the structure
Added new kernel params for gart usage limitation
Added initialization of sa manager
Fixed debug messages
Remove support for LDS in 32 bit
Changed code to support mmap of doorbell pages from userspace
Added documentation for apertures

v4: Replaced RCU by SRCU for kfd_process list management

v5:

Move amdkfd from drm/radeon/ to drm/amd/
Rename kfd_aperture.c to kfd_flat_memory.c
Protect against multiple init calls
MQD size is H/W dependent so moved it to device info structure
Rename kfd_mem_obj structure's members
Use delayed function for process tear-down

Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>

1 files changed, 97 insertions, 0 deletions

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c b/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
new file mode 100644
index 000000000000..2458ab7c0c6e
--- /dev/null
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_pasid.c
@@ -0,0 +1,97 @@
+/*
+ * Copyright 2014 Advanced Micro Devices, Inc.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
+ * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+ * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ * OTHER DEALINGS IN THE SOFTWARE.
+ */
+
+#include <linux/slab.h>
+#include <linux/types.h>
+#include "kfd_priv.h"
+
+static unsigned long *pasid_bitmap;
+static unsigned int pasid_limit;
+static DEFINE_MUTEX(pasid_mutex);
+
+int kfd_pasid_init(void)
+{
+	pasid_limit = max_num_of_processes;
+
+	pasid_bitmap = kzalloc(DIV_ROUND_UP(pasid_limit, BITS_PER_BYTE),
+				GFP_KERNEL);
+	if (!pasid_bitmap)
+		return -ENOMEM;
+
+	set_bit(0, pasid_bitmap); /* PASID 0 is reserved. */
+
+	return 0;
+}
+
+void kfd_pasid_exit(void)
+{
+	kfree(pasid_bitmap);
+}
+
+bool kfd_set_pasid_limit(unsigned int new_limit)
+{
+	if (new_limit < pasid_limit) {
+		bool ok;
+
+		mutex_lock(&pasid_mutex);
+
+		/* ensure that no pasids >= new_limit are in-use */
+		ok = (find_next_bit(pasid_bitmap, pasid_limit, new_limit) ==
+								pasid_limit);
+		if (ok)
+			pasid_limit = new_limit;
+
+		mutex_unlock(&pasid_mutex);
+
+		return ok;
+	}
+
+	return true;
+}
+
+inline unsigned int kfd_get_pasid_limit(void)
+{
+	return pasid_limit;
+}
+
+unsigned int kfd_pasid_alloc(void)
+{
+	unsigned int found;
+
+	mutex_lock(&pasid_mutex);
+
+	found = find_first_zero_bit(pasid_bitmap, pasid_limit);
+	if (found == pasid_limit)
+		found = 0;
+	else
+		set_bit(found, pasid_bitmap);
+
+	mutex_unlock(&pasid_mutex);
+
+	return found;
+}
+
+void kfd_pasid_free(unsigned int pasid)
+{
+	BUG_ON(pasid == 0 || pasid >= pasid_limit);
+	clear_bit(pasid, pasid_bitmap);
+}