gpu: nvgpu: Add configurable comptag_mem_deduct sysfs node per device

Adding a comptag_mem_deduct in the platform_gk20a has certain problems:
1) It's not really convenient for platform users to configure it.
2) All products using the same GPU have to share the same configuration.

So this patch moves this comptag_mem_deduct from struct platform_gk20a
to struct gr_gk20a (per device). And it adds an sysfs node for products
or platform users to easily configure from user space.

Note: The comptag memory will not be allocated until the GPU driver goes
through the final poweron routine. So the user space has a small window
to configure this sysfs node.

Bug 2327574
Bug 2284925

Change-Id: Ie7d00b082704e422645c0ea254b59e22f9fc3b7f
Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1810334
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/os/linux/sysfs.c b/drivers/gpu/nvgpu/os/linux/sysfs.c
index a42070d4..5eef8bfa 100644
--- a/drivers/gpu/nvgpu/os/linux/sysfs.c
+++ b/drivers/gpu/nvgpu/os/linux/sysfs.c
@@ -22,6 +22,7 @@
 #include <nvgpu/nvhost.h>
 #include <nvgpu/ptimer.h>
 
+#include "os_linux.h"
 #include "sysfs.h"
 #include "platform_gk20a.h"
 #include "gk20a/gr_gk20a.h"
@@ -1159,6 +1160,40 @@ static DEVICE_ATTR(gfxp_wfi_timeout_count, (S_IRWXU|S_IRGRP|S_IROTH),
 static DEVICE_ATTR(gfxp_wfi_timeout_unit, (S_IRWXU|S_IRGRP|S_IROTH),
                 gfxp_wfi_timeout_unit_read, gfxp_wfi_timeout_unit_store);
 
+static ssize_t comptag_mem_deduct_store(struct device *dev,
+                                        struct device_attribute *attr,
+                                        const char *buf, size_t count)
+{
+        struct gk20a *g = get_gk20a(dev);
+        unsigned long val;
+
+        if (kstrtoul(buf, 10, &val) < 0)
+                return -EINVAL;
+
+        if (val >= totalram_size_in_mb) {
+                dev_err(dev, "comptag_mem_deduct can not be set above %lu",
+                        totalram_size_in_mb);
+                return -EINVAL;
+        }
+
+        g->gr.comptag_mem_deduct = val;
+        /* Deduct the part taken by the running system */
+        g->gr.max_comptag_mem -= val;
+
+        return count;
+}
+
+static ssize_t comptag_mem_deduct_show(struct device *dev,
+                                       struct device_attribute *attr, char *buf)
+{
+        struct gk20a *g = get_gk20a(dev);
+
+        return sprintf(buf, "%d\n", g->gr.comptag_mem_deduct);
+}
+
+static DEVICE_ATTR(comptag_mem_deduct, ROOTRW,
+                   comptag_mem_deduct_show, comptag_mem_deduct_store);
+
 void nvgpu_remove_sysfs(struct device *dev)
 {
         device_remove_file(dev, &dev_attr_elcg_enable);
@@ -1200,6 +1235,8 @@ void nvgpu_remove_sysfs(struct device *dev)
         device_remove_file(dev, &dev_attr_gfxp_wfi_timeout_count);
         device_remove_file(dev, &dev_attr_gfxp_wfi_timeout_unit);
 
+        device_remove_file(dev, &dev_attr_comptag_mem_deduct);
+
         if (strcmp(dev_name(dev), "gpu.0")) {
                 struct kobject *kobj = &dev->kobj;
                 struct device *parent = container_of((kobj->parent),
@@ -1252,6 +1289,8 @@ int nvgpu_create_sysfs(struct device *dev)
         error |= device_create_file(dev, &dev_attr_gfxp_wfi_timeout_count);
         error |= device_create_file(dev, &dev_attr_gfxp_wfi_timeout_unit);
 
+        error |= device_create_file(dev, &dev_attr_comptag_mem_deduct);
+
         if (strcmp(dev_name(dev), "gpu.0")) {
                 struct kobject *kobj = &dev->kobj;
                 struct device *parent = container_of((kobj->parent),