Add optional reset support which is mentioned in vivante,gc.yaml to
allow the driver to work on SoCs whose reset signal is asserted by default
Signed-off-by: Philippe Lecointre <philippe.lecointre@xxxxxxxxxxxxxxx>
Reviewed-by: Simon Lenain <simon.lenain@xxxxxxxxxxxxxxx>
---
v3:
- Rework to match initial feedback
---
drivers/gpu/drm/etnaviv/etnaviv_gpu.c | 37 +++++++++++++++++++++++++++
drivers/gpu/drm/etnaviv/etnaviv_gpu.h | 1 +
2 files changed, 38 insertions(+)
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
index 2d4c112ce033..1961ebac315a 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.c
@@ -13,6 +13,7 @@
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/regulator/consumer.h>
+#include <linux/reset.h>
#include <linux/thermal.h>
#include "etnaviv_cmdbuf.h"
@@ -172,6 +173,25 @@ int etnaviv_gpu_get_param(struct etnaviv_gpu *gpu, u32 param, u64 *value)
return 0;
}
+static int etnaviv_gpu_reset_deassert(struct etnaviv_gpu *gpu)
+{
+ int ret;
+
+ /* 32 core clock cycles (slowest clock) required before deassertion */
+ /* 1 microsecond might match all implementations without computation */
+ usleep_range(1, 2);
+
+ ret = reset_control_deassert(gpu->rst);
+ if (ret)
+ return ret;
+
+ /* 128 core clock cycles (slowest clock) required before any activity on AHB */
+ /* 1 microsecond might match all implementations without computation */
+ usleep_range(1, 2);
+
+ return 0;
+}
+
static inline bool etnaviv_is_model_rev(struct etnaviv_gpu *gpu, u32 model, u32 revision)
{
return gpu->identity.model == model &&
@@ -799,6 +819,12 @@ int etnaviv_gpu_init(struct etnaviv_gpu *gpu)
goto pm_put;
}
+ ret = etnaviv_gpu_reset_deassert(gpu);
+ if (ret) {
+ dev_err(gpu->dev, "GPU reset deassert failed\n");
+ goto fail;
+ }
+
etnaviv_hw_identify(gpu);
if (gpu->identity.model == 0) {
@@ -1860,6 +1886,17 @@ static int etnaviv_gpu_platform_probe(struct platform_device *pdev)
if (IS_ERR(gpu->mmio))
return PTR_ERR(gpu->mmio);
+
+ /* Get Reset: */
+ gpu->rst = devm_reset_control_get_optional_exclusive(&pdev->dev, NULL);
+ if (IS_ERR(gpu->rst))
+ return dev_err_probe(dev, PTR_ERR(gpu->rst),
+ "failed to get reset\n");
+
+ err = reset_control_assert(gpu->rst);
+ if (err)
+ return dev_err_probe(dev, err, "failed to assert reset\n");
+
/* Get Interrupt: */
gpu->irq = platform_get_irq(pdev, 0);
if (gpu->irq < 0)
diff --git a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
index 4d8a7d48ade3..0985ea548b82 100644
--- a/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
+++ b/drivers/gpu/drm/etnaviv/etnaviv_gpu.h
@@ -158,6 +158,7 @@ struct etnaviv_gpu {
struct clk *clk_reg;
struct clk *clk_core;
struct clk *clk_shader;
+ struct reset_control *rst;
unsigned int freq_scale;
unsigned int fe_waitcycles;
--
2.19.1
