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Subject[PATCH 47/83] hsa/radeon: Add support allocating kernel doorbells
Date
From: Ben Goz <ben.goz@amd.com>

This patch adds infrastructure to allocate doorbells which are not exposed to
user space.

Signed-off-by: Ben Goz <ben.goz@amd.com>
Signed-off-by: Oded Gabbay <oded.gabbay@amd.com>
---
drivers/gpu/hsa/radeon/kfd_doorbell.c | 76 ++++++++++++++++++++++++++++++++++-
drivers/gpu/hsa/radeon/kfd_priv.h | 5 +++
2 files changed, 80 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/hsa/radeon/kfd_doorbell.c b/drivers/gpu/hsa/radeon/kfd_doorbell.c
index 3de8a02..abf4cb0 100644
--- a/drivers/gpu/hsa/radeon/kfd_doorbell.c
+++ b/drivers/gpu/hsa/radeon/kfd_doorbell.c
@@ -23,6 +23,16 @@
#include "kfd_priv.h"
#include <linux/mm.h>
#include <linux/mman.h>
+#include <linux/slab.h>
+
+/*
+ * This extension supports a kernel level doorbells management for the kernel queues
+ * basically the last doorbells page is devoted to kernel queues and that's assures
+ * that any user process won't get access to the kernel doorbells page
+ */
+static DEFINE_MUTEX(doorbell_mutex);
+static unsigned long doorbell_available_index[DIV_ROUND_UP(MAX_PROCESS_QUEUES, BITS_PER_LONG)] = { 0 };
+#define KERNEL_DOORBELL_PASID 1

/*
* Each device exposes a doorbell aperture, a PCI MMIO aperture that
@@ -67,7 +77,22 @@ void radeon_kfd_doorbell_init(struct kfd_dev *kfd)

kfd->doorbell_base = kfd->shared_resources.doorbell_physical_address + doorbell_start_offset;
kfd->doorbell_id_offset = doorbell_start_offset / sizeof(doorbell_t);
- kfd->doorbell_process_limit = doorbell_process_limit;
+ kfd->doorbell_process_limit = doorbell_process_limit - 1;
+
+ kfd->doorbell_kernel_ptr = ioremap(kfd->doorbell_base, doorbell_process_allocation());
+ BUG_ON(!kfd->doorbell_kernel_ptr);
+
+ pr_debug("kfd: doorbell initialization\n"
+ " doorbell base == 0x%08lX\n"
+ " doorbell_id_offset == 0x%08lu\n"
+ " doorbell_process_limit == 0x%08lu\n"
+ " doorbell_kernel_offset == 0x%08lX\n"
+ " doorbell aperture size == 0x%08lX\n"
+ " doorbell kernel address == 0x%08lX\n",
+ (uintptr_t)kfd->doorbell_base, kfd->doorbell_id_offset, doorbell_process_limit,
+ (uintptr_t)kfd->doorbell_base, kfd->shared_resources.doorbell_aperture_size,
+ (uintptr_t)kfd->doorbell_kernel_ptr);
+
}

/* This is the /dev/kfd mmap (for doorbell) implementation. We intend that this is only called through map_doorbells,
@@ -136,6 +161,53 @@ map_doorbells(struct file *devkfd, struct kfd_process *process, struct kfd_dev *
return 0;
}

+/* get kernel iomem pointer for a doorbell */
+u32 __iomem *radeon_kfd_get_kernel_doorbell(struct kfd_dev *kfd, unsigned int *doorbell_off)
+{
+ u32 inx;
+
+ BUG_ON(!kfd || !doorbell_off);
+
+ mutex_lock(&doorbell_mutex);
+ inx = find_first_zero_bit(doorbell_available_index, MAX_PROCESS_QUEUES);
+ __set_bit(inx, doorbell_available_index);
+ mutex_unlock(&doorbell_mutex);
+
+ if (inx >= MAX_PROCESS_QUEUES)
+ return NULL;
+
+ /* caluculating the kernel doorbell offset using "faked" kernel pasid that allocated for kernel queues only */
+ *doorbell_off = KERNEL_DOORBELL_PASID * (doorbell_process_allocation()/sizeof(doorbell_t)) + inx;
+
+ pr_debug("kfd: get kernel queue doorbell\n"
+ " doorbell offset == 0x%08d\n"
+ " kernel address == 0x%08lX\n",
+ *doorbell_off, (uintptr_t)(kfd->doorbell_kernel_ptr + inx));
+
+ return kfd->doorbell_kernel_ptr + inx;
+}
+
+void radeon_kfd_release_kernel_doorbell(struct kfd_dev *kfd, u32 __iomem *db_addr)
+{
+ unsigned int inx;
+
+ BUG_ON(!kfd || !db_addr);
+
+ inx = (unsigned int)(db_addr - kfd->doorbell_kernel_ptr);
+
+ mutex_lock(&doorbell_mutex);
+ __clear_bit(inx, doorbell_available_index);
+ mutex_unlock(&doorbell_mutex);
+}
+
+inline void write_kernel_doorbell(u32 __iomem *db, u32 value)
+{
+ if (db) {
+ writel(value, db);
+ pr_debug("writing %d to doorbell address 0x%p\n", value, db);
+ }
+}
+
/* Get the user-mode address of a doorbell. Assumes that the process mutex is being held. */
doorbell_t __user *radeon_kfd_get_doorbell(struct file *devkfd, struct kfd_process *process, struct kfd_dev *dev,
unsigned int doorbell_index)
@@ -152,6 +224,8 @@ doorbell_t __user *radeon_kfd_get_doorbell(struct file *devkfd, struct kfd_proce
pdd = radeon_kfd_get_process_device_data(dev, process);
BUG_ON(pdd == NULL); /* map_doorbells would have failed otherwise */

+ pr_debug("doorbell value on creation 0x%x\n", pdd->doorbell_mapping[doorbell_index]);
+
return &pdd->doorbell_mapping[doorbell_index];
}

diff --git a/drivers/gpu/hsa/radeon/kfd_priv.h b/drivers/gpu/hsa/radeon/kfd_priv.h
index 14a3f9b..df17387 100644
--- a/drivers/gpu/hsa/radeon/kfd_priv.h
+++ b/drivers/gpu/hsa/radeon/kfd_priv.h
@@ -95,6 +95,7 @@ struct kfd_dev {
* at the start)
*/
size_t doorbell_process_limit; /* Number of processes we have doorbell space for. */
+ u32 __iomem *doorbell_kernel_ptr; /* this is a pointer for a doorbells page used by kernel queue */

struct kgd2kfd_shared_resources shared_resources;

@@ -288,6 +289,10 @@ void radeon_kfd_doorbell_init(struct kfd_dev *kfd);
int radeon_kfd_doorbell_mmap(struct kfd_process *process, struct vm_area_struct *vma);
doorbell_t __user *radeon_kfd_get_doorbell(struct file *devkfd, struct kfd_process *process, struct kfd_dev *dev,
unsigned int doorbell_index);
+u32 __iomem *radeon_kfd_get_kernel_doorbell(struct kfd_dev *kfd, unsigned int *doorbell_off);
+void radeon_kfd_release_kernel_doorbell(struct kfd_dev *kfd, u32 __iomem *db_addr);
+u32 read_kernel_doorbell(u32 __iomem *db);
+void write_kernel_doorbell(u32 __iomem *db, u32 value);
unsigned int radeon_kfd_queue_id_to_doorbell(struct kfd_dev *kfd, struct kfd_process *process, unsigned int queue_id);

extern struct device *kfd_device;
--
1.9.1


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