[PATCH v1 16/30] gpu: host1x: Support OPP and SoC core voltage scaling

Dmitry Osipenko
2020-11-04T23:48:34Z

Add initial OPP and SoC core voltage scaling support to the Host1x driver.
This is required for enabling system-wide DVFS on older Tegra SoCs.

Tested-by: Peter Geis <pgwipeout@gmail.com>
Tested-by: Nicolas Chauvet <kwizart@gmail.com>
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/gpu/host1x/Kconfig | 1 +
drivers/gpu/host1x/dev.c | 87 ++++++++++++++++++++++++++++++++++++++
2 files changed, 88 insertions(+)

diff --git a/drivers/gpu/host1x/Kconfig b/drivers/gpu/host1x/Kconfig
index 6dab94adf25e..fba4207c35a4 100644
--- a/drivers/gpu/host1x/Kconfig
+++ b/drivers/gpu/host1x/Kconfig
@@ -3,6 +3,7 @@ config TEGRA_HOST1X
tristate "NVIDIA Tegra host1x driver"
depends on ARCH_TEGRA || (ARM && COMPILE_TEST)
select IOMMU_IOVA
+ select PM_OPP
help
Driver for the NVIDIA Tegra host1x hardware.

diff --git a/drivers/gpu/host1x/dev.c b/drivers/gpu/host1x/dev.c
index d0ebb70e2fdd..06e65dc1ab19 100644
--- a/drivers/gpu/host1x/dev.c
+++ b/drivers/gpu/host1x/dev.c
@@ -13,6 +13,9 @@
#include <linux/of_device.h>
#include <linux/of.h>
#include <linux/slab.h>
+#include <linux/pm_opp.h>
+
+#include <soc/tegra/fuse.h>

#define CREATE_TRACE_POINTS
#include <trace/events/host1x.h>
@@ -341,6 +344,85 @@ static void host1x_iommu_exit(struct host1x *host)
}
}

+static void host1x_deinit_opp_table(void *data)
+{
+ struct device *dev = data;
+ struct opp_table *opp_table;
+
+ opp_table = dev_pm_opp_get_opp_table(dev);
+ dev_pm_opp_of_remove_table(dev);
+ dev_pm_opp_put_supported_hw(opp_table);
+ dev_pm_opp_put_regulators(opp_table);
+ dev_pm_opp_put_opp_table(opp_table);
+}
+
+static int devm_host1x_init_opp_table(struct host1x *host)
+{
+ struct opp_table *opp_table, *hw_opp_table;
+ const char *rname = "core";
+ u32 hw_version;
+ int err;
+
+ /* voltage scaling is optional */
+ if (device_property_present(host->dev, "core-supply"))
+ opp_table = dev_pm_opp_set_regulators(host->dev, &rname, 1);
+ else
+ opp_table = dev_pm_opp_get_opp_table(host->dev);
+
+ if (IS_ERR(opp_table))
+ return dev_err_probe(host->dev, PTR_ERR(opp_table),
+ "failed to prepare OPP table\n");
+
+ if (of_machine_is_compatible("nvidia,tegra20"))
+ hw_version = BIT(tegra_sku_info.soc_process_id);
+ else
+ hw_version = BIT(tegra_sku_info.soc_speedo_id);
+
+ hw_opp_table = dev_pm_opp_set_supported_hw(host->dev, &hw_version, 1);
+ err = PTR_ERR_OR_ZERO(hw_opp_table);
+ if (err) {
+ dev_err(host->dev, "failed to set supported HW: %d\n", err);
+ goto put_table;
+ }
+
+ /*
+ * OPP table presence is optional and we want the set_rate() of OPP
+ * API to work similarly to clk_set_rate() if table is missing in a
+ * device-tree. The add_table() errors out if OPP is missing in DT.
+ */
+ if (device_property_present(host->dev, "operating-points-v2")) {
+ err = dev_pm_opp_of_add_table(host->dev);
+ if (err) {
+ dev_err(host->dev, "failed to add OPP table: %d\n", err);
+ goto put_hw;
+ }
+ }
+
+ /* first dummy rate-set initializes voltage vote */
+ err = dev_pm_opp_set_rate(host->dev, clk_get_rate(host->clk));
+ if (err) {
+ dev_err(host->dev, "failed to initialize OPP clock: %d\n", err);
+ goto remove_table;
+ }
+
+ err = devm_add_action(host->dev, host1x_deinit_opp_table, host->dev);
+ if (err)
+ goto remove_table;
+
+ dev_info(host->dev, "OPP HW ver. 0x%x\n", hw_version);
+
+ return 0;
+
+remove_table:
+ dev_pm_opp_of_remove_table(host->dev);
+put_hw:
+ dev_pm_opp_put_supported_hw(opp_table);
+put_table:
+ dev_pm_opp_put_regulators(opp_table);
+
+ return err;
+}
+
static int host1x_probe(struct platform_device *pdev)
{
struct host1x *host;
@@ -424,6 +506,11 @@ static int host1x_probe(struct platform_device *pdev)
return err;
}

+ err = devm_host1x_init_opp_table(host);
+ if (err < 0)
+ return dev_err_probe(&pdev->dev, err,
+ "failed to initialize OPP\n");
+
err = host1x_iommu_init(host);
if (err < 0) {
dev_err(&pdev->dev, "failed to setup IOMMU: %d\n", err);
--
2.27.0