gpu: nvgpu: Abstract IO aperture accessors

Add abstraction of IO aperture accessors. Add new functions
gk20a_io_exists() and gk20a_io_valid_reg() to remove dependencies to
aperture fields from common code.

Implement Linux version of the abstraction by moving gk20a_readl()
and gk20a_writel() to new Linux specific io.c. Move the fields
defining IO aperture to nvgpu_os_linux.

Add t19x specific IO aperture initialization functions and add t19x
specific section to nvgpu_os_linux.

JIRA NVGPU-259

Change-Id: I09e79cda60d11a20d1099a9aaa6d2375236e94ce
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1569698
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 63 insertions, 14 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/module.c b/drivers/gpu/nvgpu/common/linux/module.c
index 52f987b2..fe3e4e6f 100644
--- a/drivers/gpu/nvgpu/common/linux/module.c
+++ b/drivers/gpu/nvgpu/common/linux/module.c
@@ -137,6 +137,23 @@ void gk20a_idle(struct gk20a *g)
         }
 }
 
+/*
+ * Undoes gk20a_lockout_registers().
+ */
+static int gk20a_restore_registers(struct gk20a *g)
+{
+        struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
+
+        l->regs = l->regs_saved;
+        l->bar1 = l->bar1_saved;
+
+#ifdef CONFIG_TEGRA_19x_GPU
+        t19x_restore_registers(g);
+#endif
+
+        return 0;
+}
+
 int gk20a_pm_finalize_poweron(struct device *dev)
 {
         struct gk20a *g = get_gk20a(dev);
@@ -198,6 +215,27 @@ done:
         return err;
 }
 
+/*
+ * Locks out the driver from accessing GPU registers. This prevents access to
+ * thse registers after the GPU has been clock or power gated. This should help
+ * find annoying bugs where register reads and writes are silently dropped
+ * after the GPU has been turned off. On older chips these reads and writes can
+ * also lock the entire CPU up.
+ */
+static int gk20a_lockout_registers(struct gk20a *g)
+{
+        struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
+
+        l->regs = NULL;
+        l->bar1 = NULL;
+
+#ifdef CONFIG_TEGRA_19x_GPU
+        t19x_lockout_registers(g);
+#endif
+
+        return 0;
+}
+
 static int gk20a_pm_prepare_poweroff(struct device *dev)
 {
         struct gk20a *g = get_gk20a(dev);
@@ -511,6 +549,8 @@ static irqreturn_t gk20a_intr_thread_stall(int irq, void *dev_id)
 
 void gk20a_remove_support(struct gk20a *g)
 {
+        struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
+
         tegra_unregister_idle_unidle(gk20a_do_idle);
 
         nvgpu_kfree(g, g->dbg_regops_tmp_buf);
@@ -535,36 +575,41 @@ void gk20a_remove_support(struct gk20a *g)
 
         /* free mappings to registers, etc */
 
-        if (g->regs) {
-                iounmap(g->regs);
-                g->regs = NULL;
+        if (l->regs) {
+                iounmap(l->regs);
+                l->regs = NULL;
         }
-        if (g->bar1) {
-                iounmap(g->bar1);
-                g->bar1 = NULL;
+        if (l->bar1) {
+                iounmap(l->bar1);
+                l->bar1 = NULL;
         }
+
+#ifdef CONFIG_TEGRA_19x_GPU
+        t19x_remove_support(g);
+#endif
 }
 
 static int gk20a_init_support(struct platform_device *dev)
 {
         int err = 0;
         struct gk20a *g = get_gk20a(&dev->dev);
+        struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
 
         tegra_register_idle_unidle(gk20a_do_idle, gk20a_do_unidle, g);
 
-        g->regs = gk20a_ioremap_resource(dev, GK20A_BAR0_IORESOURCE_MEM,
-                                         &g->reg_mem);
-        if (IS_ERR(g->regs)) {
+        l->regs = gk20a_ioremap_resource(dev, GK20A_BAR0_IORESOURCE_MEM,
+                                         &l->reg_mem);
+        if (IS_ERR(l->regs)) {
                 nvgpu_err(g, "failed to remap gk20a registers");
-                err = PTR_ERR(g->regs);
+                err = PTR_ERR(l->regs);
                 goto fail;
         }
 
-        g->bar1 = gk20a_ioremap_resource(dev, GK20A_BAR1_IORESOURCE_MEM,
-                                         &g->bar1_mem);
-        if (IS_ERR(g->bar1)) {
+        l->bar1 = gk20a_ioremap_resource(dev, GK20A_BAR1_IORESOURCE_MEM,
+                                         &l->bar1_mem);
+        if (IS_ERR(l->bar1)) {
                 nvgpu_err(g, "failed to remap gk20a bar1");
-                err = PTR_ERR(g->bar1);
+                err = PTR_ERR(l->bar1);
                 goto fail;
         }
 
@@ -584,6 +629,10 @@ static int gk20a_init_support(struct platform_device *dev)
                         goto fail;
         }
 
+#ifdef CONFIG_TEGRA_19x_GPU
+        t19x_init_support(g);
+#endif
+
         return 0;
 
 fail: