gpu: host1x: Add context device management code

Add code to register context devices from device tree, allocate them
out and manage their refcounts.

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>

diff --git a/drivers/gpu/host1x/Makefile b/drivers/gpu/host1x/Makefile
index c891a3e..28f7aae 100644 (file)
--- a/drivers/gpu/host1x/Makefile
+++ b/drivers/gpu/host1x/Makefile
@@ -17,5 +17,8 @@ host1x-y = \
        hw/host1x06.o \
        hw/host1x07.o
 
+host1x-$(CONFIG_IOMMU_API) += \
+       context.o
+
 obj-$(CONFIG_TEGRA_HOST1X) += host1x.o
 obj-$(CONFIG_TEGRA_HOST1X_CONTEXT_BUS) += context_bus.o

diff --git a/drivers/gpu/host1x/context.c b/drivers/gpu/host1x/context.c
new file mode 100644 (file)
index 0000000..b08cf11
--- /dev/null
+++ b/drivers/gpu/host1x/context.c
@@ -0,0 +1,160 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2021, NVIDIA Corporation.
+ */
+
+#include <linux/device.h>
+#include <linux/kref.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/pid.h>
+#include <linux/slab.h>
+
+#include "context.h"
+#include "dev.h"
+
+int host1x_memory_context_list_init(struct host1x *host1x)
+{
+       struct host1x_memory_context_list *cdl = &host1x->context_list;
+       struct device_node *node = host1x->dev->of_node;
+       struct host1x_memory_context *ctx;
+       unsigned int i;
+       int err;
+
+       cdl->devs = NULL;
+       cdl->len = 0;
+       mutex_init(&cdl->lock);
+
+       err = of_property_count_u32_elems(node, "iommu-map");
+       if (err < 0)
+               return 0;
+
+       cdl->devs = kcalloc(err, sizeof(*cdl->devs), GFP_KERNEL);
+       if (!cdl->devs)
+               return -ENOMEM;
+       cdl->len = err / 4;
+
+       for (i = 0; i < cdl->len; i++) {
+               struct iommu_fwspec *fwspec;
+
+               ctx = &cdl->devs[i];
+
+               ctx->host = host1x;
+
+               device_initialize(&ctx->dev);
+
+               /*
+                * Due to an issue with T194 NVENC, only 38 bits can be used.
+                * Anyway, 256GiB of IOVA ought to be enough for anyone.
+                */
+               ctx->dma_mask = DMA_BIT_MASK(38);
+               ctx->dev.dma_mask = &ctx->dma_mask;
+               ctx->dev.coherent_dma_mask = ctx->dma_mask;
+               dev_set_name(&ctx->dev, "host1x-ctx.%d", i);
+               ctx->dev.bus = &host1x_context_device_bus_type;
+               ctx->dev.parent = host1x->dev;
+
+               dma_set_max_seg_size(&ctx->dev, UINT_MAX);
+
+               err = device_add(&ctx->dev);
+               if (err) {
+                       dev_err(host1x->dev, "could not add context device %d: %d\n", i, err);
+                       goto del_devices;
+               }
+
+               err = of_dma_configure_id(&ctx->dev, node, true, &i);
+               if (err) {
+                       dev_err(host1x->dev, "IOMMU configuration failed for context device %d: %d\n",
+                               i, err);
+                       device_del(&ctx->dev);
+                       goto del_devices;
+               }
+
+               fwspec = dev_iommu_fwspec_get(&ctx->dev);
+               if (!fwspec || !device_iommu_mapped(&ctx->dev)) {
+                       dev_err(host1x->dev, "Context device %d has no IOMMU!\n", i);
+                       device_del(&ctx->dev);
+                       goto del_devices;
+               }
+
+               ctx->stream_id = fwspec->ids[0] & 0xffff;
+       }
+
+       return 0;
+
+del_devices:
+       while (i--)
+               device_del(&cdl->devs[i].dev);
+
+       kfree(cdl->devs);
+       cdl->len = 0;
+
+       return err;
+}
+
+void host1x_memory_context_list_free(struct host1x_memory_context_list *cdl)
+{
+       unsigned int i;
+
+       for (i = 0; i < cdl->len; i++)
+               device_del(&cdl->devs[i].dev);
+
+       kfree(cdl->devs);
+       cdl->len = 0;
+}
+
+struct host1x_memory_context *host1x_memory_context_alloc(struct host1x *host1x,
+                                                         struct pid *pid)
+{
+       struct host1x_memory_context_list *cdl = &host1x->context_list;
+       struct host1x_memory_context *free = NULL;
+       int i;
+
+       if (!cdl->len)
+               return ERR_PTR(-EOPNOTSUPP);
+
+       mutex_lock(&cdl->lock);
+
+       for (i = 0; i < cdl->len; i++) {
+               struct host1x_memory_context *cd = &cdl->devs[i];
+
+               if (cd->owner == pid) {
+                       refcount_inc(&cd->ref);
+                       mutex_unlock(&cdl->lock);
+                       return cd;
+               } else if (!cd->owner && !free) {
+                       free = cd;
+               }
+       }
+
+       if (!free) {
+               mutex_unlock(&cdl->lock);
+               return ERR_PTR(-EBUSY);
+       }
+
+       refcount_set(&free->ref, 1);
+       free->owner = get_pid(pid);
+
+       mutex_unlock(&cdl->lock);
+
+       return free;
+}
+EXPORT_SYMBOL_GPL(host1x_memory_context_alloc);
+
+void host1x_memory_context_get(struct host1x_memory_context *cd)
+{
+       refcount_inc(&cd->ref);
+}
+EXPORT_SYMBOL_GPL(host1x_memory_context_get);
+
+void host1x_memory_context_put(struct host1x_memory_context *cd)
+{
+       struct host1x_memory_context_list *cdl = &cd->host->context_list;
+
+       if (refcount_dec_and_mutex_lock(&cd->ref, &cdl->lock)) {
+               put_pid(cd->owner);
+               cd->owner = NULL;
+               mutex_unlock(&cdl->lock);
+       }
+}
+EXPORT_SYMBOL_GPL(host1x_memory_context_put);

diff --git a/drivers/gpu/host1x/context.h b/drivers/gpu/host1x/context.h
new file mode 100644 (file)
index 0000000..3e03bc1
--- /dev/null
+++ b/drivers/gpu/host1x/context.h
@@ -0,0 +1,38 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+/*
+ * Host1x context devices
+ *
+ * Copyright (c) 2020, NVIDIA Corporation.
+ */
+
+#ifndef __HOST1X_CONTEXT_H
+#define __HOST1X_CONTEXT_H
+
+#include <linux/mutex.h>
+#include <linux/refcount.h>
+
+struct host1x;
+
+extern struct bus_type host1x_context_device_bus_type;
+
+struct host1x_memory_context_list {
+       struct mutex lock;
+       struct host1x_memory_context *devs;
+       unsigned int len;
+};
+
+#ifdef CONFIG_IOMMU_API
+int host1x_memory_context_list_init(struct host1x *host1x);
+void host1x_memory_context_list_free(struct host1x_memory_context_list *cdl);
+#else
+static inline int host1x_memory_context_list_init(struct host1x *host1x)
+{
+       return 0;
+}
+
+static inline void host1x_memory_context_list_free(struct host1x_memory_context_list *cdl)
+{
+}
+#endif
+
+#endif

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index 80c685a..89cc79a 100644 (file)
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -28,6 +28,7 @@
 
 #include "bus.h"
 #include "channel.h"
+#include "context.h"
 #include "debug.h"
 #include "dev.h"
 #include "intr.h"
@@ -503,10 +504,16 @@ static int host1x_probe(struct platform_device *pdev)
                goto iommu_exit;
        }
 
+       err = host1x_memory_context_list_init(host);
+       if (err) {
+               dev_err(&pdev->dev, "failed to initialize context list\n");
+               goto free_channels;
+       }
+
        err = host1x_syncpt_init(host);
        if (err) {
                dev_err(&pdev->dev, "failed to initialize syncpts\n");
-               goto free_channels;
+               goto free_contexts;
        }
 
        err = host1x_intr_init(host, syncpt_irq);
@@ -550,6 +557,8 @@ pm_disable:
        host1x_intr_deinit(host);
 deinit_syncpt:
        host1x_syncpt_deinit(host);
+free_contexts:
+       host1x_memory_context_list_free(&host->context_list);
 free_channels:
        host1x_channel_list_free(&host->channel_list);
 iommu_exit:
@@ -571,6 +580,7 @@ static int host1x_remove(struct platform_device *pdev)
 
        host1x_intr_deinit(host);
        host1x_syncpt_deinit(host);
+       host1x_memory_context_list_free(&host->context_list);
        host1x_channel_list_free(&host->channel_list);
        host1x_iommu_exit(host);
        host1x_bo_cache_destroy(&host->cache);

diff --git a/drivers/gpu/host1x/dev.h b/drivers/gpu/host1x/dev.h
index ca4b082..7552a45 100644 (file)
--- a/drivers/gpu/host1x/dev.h
+++ b/drivers/gpu/host1x/dev.h
@@ -14,6 +14,7 @@
 
 #include "cdma.h"
 #include "channel.h"
+#include "context.h"
 #include "intr.h"
 #include "job.h"
 #include "syncpt.h"
@@ -141,6 +142,7 @@ struct host1x {
        struct mutex syncpt_mutex;
 
        struct host1x_channel_list channel_list;
+       struct host1x_memory_context_list context_list;
 
        struct dentry *debugfs;
 

diff --git a/include/linux/host1x.h b/include/linux/host1x.h
index c0bf4e5..32a82da 100644 (file)
--- a/include/linux/host1x.h
+++ b/include/linux/host1x.h
@@ -446,4 +446,38 @@ int tegra_mipi_disable(struct tegra_mipi_device *device);
 int tegra_mipi_start_calibration(struct tegra_mipi_device *device);
 int tegra_mipi_finish_calibration(struct tegra_mipi_device *device);
 
+/* host1x memory contexts */
+
+struct host1x_memory_context {
+       struct host1x *host;
+
+       refcount_t ref;
+       struct pid *owner;
+
+       struct device dev;
+       u64 dma_mask;
+       u32 stream_id;
+};
+
+#ifdef CONFIG_IOMMU_API
+struct host1x_memory_context *host1x_memory_context_alloc(struct host1x *host1x,
+                                                         struct pid *pid);
+void host1x_memory_context_get(struct host1x_memory_context *cd);
+void host1x_memory_context_put(struct host1x_memory_context *cd);
+#else
+static inline struct host1x_memory_context *host1x_memory_context_alloc(struct host1x *host1x,
+                                                                       struct pid *pid)
+{
+       return NULL;
+}
+
+static inline void host1x_memory_context_get(struct host1x_memory_context *cd)
+{
+}
+
+static inline void host1x_memory_context_put(struct host1x_memory_context *cd)
+{
+}
+#endif
+
 #endif