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-rw-r--r--drivers/clk/tegra/cvb.c141
1 files changed, 141 insertions, 0 deletions
diff --git a/drivers/clk/tegra/cvb.c b/drivers/clk/tegra/cvb.c
new file mode 100644
index 000000000..21115c4e5
--- /dev/null
+++ b/drivers/clk/tegra/cvb.c
@@ -0,0 +1,141 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Utility functions for parsing Tegra CVB voltage tables
+ *
+ * Copyright (C) 2012-2019 NVIDIA Corporation. All rights reserved.
+ */
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/pm_opp.h>
+
+#include "cvb.h"
+
+/* cvb_mv = ((c2 * speedo / s_scale + c1) * speedo / s_scale + c0) */
+static inline int get_cvb_voltage(int speedo, int s_scale,
+ const struct cvb_coefficients *cvb)
+{
+ int mv;
+
+ /* apply only speedo scale: output mv = cvb_mv * v_scale */
+ mv = DIV_ROUND_CLOSEST(cvb->c2 * speedo, s_scale);
+ mv = DIV_ROUND_CLOSEST((mv + cvb->c1) * speedo, s_scale) + cvb->c0;
+ return mv;
+}
+
+static int round_cvb_voltage(int mv, int v_scale,
+ const struct rail_alignment *align)
+{
+ /* combined: apply voltage scale and round to cvb alignment step */
+ int uv;
+ int step = (align->step_uv ? : 1000) * v_scale;
+ int offset = align->offset_uv * v_scale;
+
+ uv = max(mv * 1000, offset) - offset;
+ uv = DIV_ROUND_UP(uv, step) * align->step_uv + align->offset_uv;
+ return uv / 1000;
+}
+
+enum {
+ DOWN,
+ UP
+};
+
+static int round_voltage(int mv, const struct rail_alignment *align, int up)
+{
+ if (align->step_uv) {
+ int uv;
+
+ uv = max(mv * 1000, align->offset_uv) - align->offset_uv;
+ uv = (uv + (up ? align->step_uv - 1 : 0)) / align->step_uv;
+ return (uv * align->step_uv + align->offset_uv) / 1000;
+ }
+ return mv;
+}
+
+static int build_opp_table(struct device *dev, const struct cvb_table *table,
+ struct rail_alignment *align,
+ int speedo_value, unsigned long max_freq)
+{
+ int i, ret, dfll_mv, min_mv, max_mv;
+
+ min_mv = round_voltage(table->min_millivolts, align, UP);
+ max_mv = round_voltage(table->max_millivolts, align, DOWN);
+
+ for (i = 0; i < MAX_DVFS_FREQS; i++) {
+ const struct cvb_table_freq_entry *entry = &table->entries[i];
+
+ if (!entry->freq || (entry->freq > max_freq))
+ break;
+
+ dfll_mv = get_cvb_voltage(speedo_value, table->speedo_scale,
+ &entry->coefficients);
+ dfll_mv = round_cvb_voltage(dfll_mv, table->voltage_scale,
+ align);
+ dfll_mv = clamp(dfll_mv, min_mv, max_mv);
+
+ ret = dev_pm_opp_add(dev, entry->freq, dfll_mv * 1000);
+ if (ret)
+ return ret;
+ }
+
+ return 0;
+}
+
+/**
+ * tegra_cvb_add_opp_table - build OPP table from Tegra CVB tables
+ * @dev: the struct device * for which the OPP table is built
+ * @tables: array of CVB tables
+ * @count: size of the previously mentioned array
+ * @process_id: process id of the HW module
+ * @speedo_id: speedo id of the HW module
+ * @speedo_value: speedo value of the HW module
+ * @max_freq: highest safe clock rate
+ *
+ * On Tegra, a CVB table encodes the relationship between operating voltage
+ * and safe maximal frequency for a given module (e.g. GPU or CPU). This
+ * function calculates the optimal voltage-frequency operating points
+ * for the given arguments and exports them via the OPP library for the
+ * given @dev. Returns a pointer to the struct cvb_table that matched
+ * or an ERR_PTR on failure.
+ */
+const struct cvb_table *
+tegra_cvb_add_opp_table(struct device *dev, const struct cvb_table *tables,
+ size_t count, struct rail_alignment *align,
+ int process_id, int speedo_id, int speedo_value,
+ unsigned long max_freq)
+{
+ size_t i;
+ int ret;
+
+ for (i = 0; i < count; i++) {
+ const struct cvb_table *table = &tables[i];
+
+ if (table->speedo_id != -1 && table->speedo_id != speedo_id)
+ continue;
+
+ if (table->process_id != -1 && table->process_id != process_id)
+ continue;
+
+ ret = build_opp_table(dev, table, align, speedo_value,
+ max_freq);
+ return ret ? ERR_PTR(ret) : table;
+ }
+
+ return ERR_PTR(-EINVAL);
+}
+
+void tegra_cvb_remove_opp_table(struct device *dev,
+ const struct cvb_table *table,
+ unsigned long max_freq)
+{
+ unsigned int i;
+
+ for (i = 0; i < MAX_DVFS_FREQS; i++) {
+ const struct cvb_table_freq_entry *entry = &table->entries[i];
+
+ if (!entry->freq || (entry->freq > max_freq))
+ break;
+
+ dev_pm_opp_remove(dev, entry->freq);
+ }
+}