Add OPP and SoC core voltage scaling support to the GR2D driver. This is required for enabling system-wide DVFS on 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/drm/tegra/gr2d.c | 136 +++++++++++++++++++++++++++++++++++ 1 file changed, 136 insertions(+)
diff --git a/drivers/gpu/drm/tegra/gr2d.c b/drivers/gpu/drm/tegra/gr2d.c index f30aa86e4c9f..6d8f9419d908 100644 --- a/drivers/gpu/drm/tegra/gr2d.c +++ b/drivers/gpu/drm/tegra/gr2d.c @@ -7,6 +7,9 @@ #include <linux/iommu.h> #include <linux/module.h> #include <linux/of_device.h> +#include <linux/pm_opp.h> + +#include <soc/tegra/fuse.h>
#include "drm.h" #include "gem.h" @@ -185,6 +188,135 @@ static const u32 gr2d_addr_regs[] = { GR2D_VA_BASE_ADDR_SB, };
+static int gr2d_init_opp_state(struct device *dev, struct gr2d *gr2d) +{ + struct dev_pm_opp *opp; + unsigned long rate; + int err; + + /* + * If voltage regulator presents, then we could select the fastest + * clock rate, but driver doesn't support power management and + * frequency scaling yet, hence the top freq OPP will vote for a + * very high voltage that will produce lot's of heat. Let's select + * OPP for the current/default rate for now. + * + * Clock rate should be pre-initialized (i.e. it's non-zero) either + * by clock driver or by assigned clocks in a device-tree. + */ + rate = clk_get_rate(gr2d->clk); + + /* find suitable OPP for the clock rate supportable by SoC speedo ID */ + opp = dev_pm_opp_find_freq_ceil(dev, &rate); + + /* + * dev_pm_opp_set_rate() doesn't search for a floor clock rate and it + * will error out if default clock rate is too high, i.e. unsupported + * by a SoC hardware version. Hence will find floor rate by ourselves. + */ + if (opp == ERR_PTR(-ERANGE)) + opp = dev_pm_opp_find_freq_floor(dev, &rate); + + err = PTR_ERR_OR_ZERO(opp); + if (err) { + dev_err(dev, "failed to get OPP for %ld Hz: %d\n", + rate, err); + return err; + } + + dev_pm_opp_put(opp); + + /* + * First dummy rate-set initializes voltage vote by setting voltage + * in accordance to the clock rate. We need to do this because GR2D + * currently doesn't support power management and clock is permanently + * enabled. + */ + err = dev_pm_opp_set_rate(dev, rate); + if (err) { + dev_err(dev, "failed to initialize OPP clock: %d\n", err); + return err; + } + + return 0; +} + +static void gr2d_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_gr2d_init_opp_table(struct device *dev, struct gr2d *gr2d) +{ + 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(dev, "core-supply")) + opp_table = dev_pm_opp_set_regulators(dev, &rname, 1); + else + opp_table = dev_pm_opp_get_opp_table(dev); + + if (IS_ERR(opp_table)) + return dev_err_probe(dev, PTR_ERR(opp_table), + "failed to prepare OPP table\n"); + + if (gr2d->soc->version == 0x20) + 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(dev, &hw_version, 1); + err = PTR_ERR_OR_ZERO(hw_opp_table); + if (err) { + dev_err(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(dev, "operating-points-v2")) { + err = dev_pm_opp_of_add_table(dev); + if (err) { + dev_err(dev, "failed to add OPP table: %d\n", err); + goto put_hw; + } + + err = gr2d_init_opp_state(dev, gr2d); + if (err) + goto remove_table; + } + + err = devm_add_action(dev, gr2d_deinit_opp_table, dev); + if (err) + goto remove_table; + + dev_info(dev, "OPP HW ver. 0x%x\n", hw_version); + + return 0; + +remove_table: + dev_pm_opp_of_remove_table(dev); +put_hw: + dev_pm_opp_put_supported_hw(opp_table); +put_table: + dev_pm_opp_put_regulators(opp_table); + + return err; +} + static int gr2d_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; @@ -209,6 +341,10 @@ static int gr2d_probe(struct platform_device *pdev) return PTR_ERR(gr2d->clk); }
+ err = devm_gr2d_init_opp_table(dev, gr2d); + if (err) + return dev_err_probe(dev, err, "failed to initialize OPP\n"); + err = clk_prepare_enable(gr2d->clk); if (err) { dev_err(dev, "cannot turn on clock\n");