gpu: nvgpu: Add GM20b GPCPLL NA mode basic support

Added basic support for GM20b GPCPLL noise-aware(NA) mode. In this
mode PLL internal DVFS mechanism is engaged, and output frequency is
scaled with voltage automatically. The scaling coefficients in this
commit are preliminary, pending characterization.

If NA mode is enabled, any frequency change is done under PLL bypass,
with no dynamic ramp allowed.

This commit kept NA mode disabled.

Bug 1555318

Change-Id: I8d96a10006155635797331bae522fb048d3dc4a0
Signed-off-by: Alex Frid <afrid@nvidia.com>
Reviewed-on: http://git-master/r/499488
GVS: Gerrit_Virtual_Submit
Reviewed-by: Yu-Huan Hsu <yhsu@nvidia.com>

1 files changed, 318 insertions, 8 deletions

diff --git a/drivers/gpu/nvgpu/gm20b/clk_gm20b.c b/drivers/gpu/nvgpu/gm20b/clk_gm20b.c
index 2e3d96ac..6f7d04dd 100644
--- a/drivers/gpu/nvgpu/gm20b/clk_gm20b.c
+++ b/drivers/gpu/nvgpu/gm20b/clk_gm20b.c
@@ -22,6 +22,7 @@
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/clk/tegra.h>
+#include <linux/tegra-fuse.h>
 
 #include "gk20a/gk20a.h"
 #include "hw_trim_gm20b.h"
@@ -29,10 +30,19 @@
 #include "hw_therm_gm20b.h"
 #include "clk_gm20b.h"
 
+#define ALLOW_NON_CALIBRATED_NA_MODE    1
+
 #define gk20a_dbg_clk(fmt, arg...) \
         gk20a_dbg(gpu_dbg_clk, fmt, ##arg)
 
-/* from vbios PLL info table */
+#define DFS_DET_RANGE   6       /* -2^6 ... 2^6-1 */
+#define SDM_DIN_RANGE   12      /* -2^12 ... 2^12-1 */
+#define DFS_EXT_CAL_EN  BIT(9)
+#define DFS_EXT_STROBE  BIT(16)
+
+#define BOOT_GPU_UV     1000000 /* gpu rail boot voltage 1.0V */
+#define ADC_SLOPE_UV    10000   /* default ADC detection slope 10mV */
+
 static struct pll_parms gpc_pll_params = {
         128000,  2600000,       /* freq */
         1300000, 2600000,       /* vco */
@@ -40,6 +50,7 @@ static struct pll_parms gpc_pll_params = {
         1, 255,                 /* M */
         8, 255,                 /* N */
         1, 31,                  /* PL */
+        -58700, 86789,          /* DFS_COEFF */
 };
 
 #ifdef CONFIG_DEBUG_FS
@@ -218,6 +229,244 @@ found_match:
         return 0;
 }
 
+/* GPCPLL NA/DVFS mode methods */
+
+/*
+ * Read ADC characteristic parmeters from fuses.
+ * Determine clibration settings.
+ */
+static int clk_config_calibration_params(struct gk20a *g)
+{
+        int slope, offs;
+        struct pll_parms *p = &gpc_pll_params;
+
+        if (!tegra_fuse_calib_gpcpll_get_adc(&slope, &offs)) {
+                p->uvdet_slope = slope;
+                p->uvdet_offs = offs;
+        }
+
+        if (!p->uvdet_slope || !p->uvdet_offs) {
+                /*
+                 * If ADC conversion slope/offset parameters are not fused
+                 * (non-production config), report error, but allow to use
+                 * boot internal calibration with default slope.
+                 */
+                gk20a_err(dev_from_gk20a(g), "ADC coeff are not fused\n");
+                return -EINVAL;
+        }
+        return 0;
+}
+
+/*
+ * Determine DFS_COEFF for the requested voltage. Always select external
+ * calibration override equal to the voltage, and set maximum detection
+ * limit "0" (to make sure that PLL output remains under F/V curve when
+ * voltage increases).
+ */
+static void clk_config_dvfs_detection(int mv, struct na_dvfs *d)
+{
+        u32 coeff, coeff_max;
+        struct pll_parms *p = &gpc_pll_params;
+
+        coeff_max = trim_sys_gpcpll_dvfs0_dfs_coeff_v(
+                trim_sys_gpcpll_dvfs0_dfs_coeff_m());
+        coeff = DIV_ROUND_CLOSEST(mv * p->coeff_slope, 1000) + p->coeff_offs;
+        coeff = DIV_ROUND_CLOSEST(coeff, 1000);
+        coeff = min(coeff, coeff_max);
+        d->dfs_coeff = coeff;
+
+        d->dfs_ext_cal = DIV_ROUND_CLOSEST(mv * 1000 - p->uvdet_offs,
+                                           p->uvdet_slope);
+        BUG_ON(abs(d->dfs_ext_cal) >= (1 << DFS_DET_RANGE));
+        d->uv_cal = p->uvdet_offs + d->dfs_ext_cal * p->uvdet_slope;
+        d->dfs_det_max = 0;
+}
+
+/*
+ * Solve equation for integer and fractional part of the effective NDIV:
+ *
+ * n_eff = n_int + 1/2 + SDM_DIN / 2^(SDM_DIN_RANGE + 1) +
+ * DVFS_COEFF * DVFS_DET_DELTA / 2^DFS_DET_RANGE
+ *
+ * The SDM_DIN LSB is finally shifted out, since it is not accessible by s/w.
+ */
+static void clk_config_dvfs_ndiv(int mv, u32 n_eff, struct na_dvfs *d)
+{
+        int n, det_delta;
+        u32 rem, rem_range;
+        struct pll_parms *p = &gpc_pll_params;
+
+        det_delta = (mv * 1000 - d->uv_cal);
+        det_delta = min(det_delta, d->dfs_det_max * p->uvdet_slope);
+        det_delta = det_delta * d->dfs_coeff;
+        det_delta = DIV_ROUND_CLOSEST(det_delta, p->uvdet_slope);
+
+        n = (int)(n_eff << DFS_DET_RANGE) - det_delta;
+        BUG_ON((n < 0) || (n > (p->max_N << DFS_DET_RANGE)));
+        d->n_int = ((u32)n) >> DFS_DET_RANGE;
+
+        rem = ((u32)n) & ((1 << DFS_DET_RANGE) - 1);
+        rem_range = SDM_DIN_RANGE + 1 - DFS_DET_RANGE;
+        d->sdm_din = (rem << rem_range) - (1 << SDM_DIN_RANGE);
+        d->sdm_din = (d->sdm_din >> BITS_PER_BYTE) & 0xff;
+}
+
+/* Voltage dependent configuration */
+static void clk_config_dvfs(struct gk20a *g, struct pll *gpll)
+{
+        struct na_dvfs *d = &gpll->dvfs;
+
+        d->mv = tegra_dvfs_predict_millivolts_t(
+                        clk_get_parent(g->clk.tegra_clk),
+                        rate_gpc2clk_to_gpu(gpll->freq));
+        clk_config_dvfs_detection(d->mv, d);
+        clk_config_dvfs_ndiv(d->mv, gpll->N, d);
+}
+
+/* Update DVFS detection settings in flight */
+static void clk_set_dfs_coeff(struct gk20a *g, u32 dfs_coeff)
+{
+        u32 data = gk20a_readl(g, trim_gpc_bcast_gpcpll_dvfs2_r());
+        data |= DFS_EXT_STROBE;
+        gk20a_writel(g, trim_gpc_bcast_gpcpll_dvfs2_r(), data);
+
+        data = gk20a_readl(g, trim_sys_gpcpll_dvfs0_r());
+        data = set_field(data, trim_sys_gpcpll_dvfs0_dfs_coeff_m(),
+                trim_sys_gpcpll_dvfs0_dfs_coeff_f(dfs_coeff));
+        gk20a_writel(g, trim_sys_gpcpll_dvfs0_r(), data);
+
+        data = gk20a_readl(g, trim_gpc_bcast_gpcpll_dvfs2_r());
+        udelay(1);
+        data &= ~DFS_EXT_STROBE;
+        gk20a_writel(g, trim_gpc_bcast_gpcpll_dvfs2_r(), data);
+}
+
+static void __maybe_unused clk_set_dfs_det_max(struct gk20a *g, u32 dfs_det_max)
+{
+        u32 data = gk20a_readl(g, trim_gpc_bcast_gpcpll_dvfs2_r());
+        data |= DFS_EXT_STROBE;
+        gk20a_writel(g, trim_gpc_bcast_gpcpll_dvfs2_r(), data);
+
+        data = gk20a_readl(g, trim_sys_gpcpll_dvfs0_r());
+        data = set_field(data, trim_sys_gpcpll_dvfs0_dfs_det_max_m(),
+                trim_sys_gpcpll_dvfs0_dfs_det_max_f(dfs_det_max));
+        gk20a_writel(g, trim_sys_gpcpll_dvfs0_r(), data);
+
+        data = gk20a_readl(g, trim_gpc_bcast_gpcpll_dvfs2_r());
+        udelay(1);
+        data &= ~DFS_EXT_STROBE;
+        gk20a_writel(g, trim_gpc_bcast_gpcpll_dvfs2_r(), data);
+}
+
+static void clk_set_dfs_ext_cal(struct gk20a *g, u32 dfs_det_cal)
+{
+        u32 data;
+
+        data = gk20a_readl(g, trim_gpc_bcast_gpcpll_dvfs2_r());
+        data &= ~(BIT(DFS_DET_RANGE + 1) - 1);
+        data |= dfs_det_cal;
+        gk20a_writel(g, trim_gpc_bcast_gpcpll_dvfs2_r(), data);
+
+        data = gk20a_readl(g, trim_sys_gpcpll_dvfs1_r());
+        udelay(1);
+        if (~trim_sys_gpcpll_dvfs1_dfs_ctrl_v(data) & DFS_EXT_CAL_EN) {
+                data = set_field(data, trim_sys_gpcpll_dvfs1_dfs_ctrl_m(),
+                        trim_sys_gpcpll_dvfs1_dfs_ctrl_f(DFS_EXT_CAL_EN));
+                gk20a_writel(g, trim_sys_gpcpll_dvfs1_r(), data);
+        }
+}
+
+static void clk_setup_dvfs_detection(struct gk20a *g, struct pll *gpll)
+{
+        struct na_dvfs *d = &gpll->dvfs;
+
+        u32 data = gk20a_readl(g, trim_gpc_bcast_gpcpll_dvfs2_r());
+        data |= DFS_EXT_STROBE;
+        gk20a_writel(g, trim_gpc_bcast_gpcpll_dvfs2_r(), data);
+
+        data = gk20a_readl(g, trim_sys_gpcpll_dvfs0_r());
+        data = set_field(data, trim_sys_gpcpll_dvfs0_dfs_coeff_m(),
+                trim_sys_gpcpll_dvfs0_dfs_coeff_f(d->dfs_coeff));
+        data = set_field(data, trim_sys_gpcpll_dvfs0_dfs_det_max_m(),
+                trim_sys_gpcpll_dvfs0_dfs_det_max_f(d->dfs_det_max));
+        gk20a_writel(g, trim_sys_gpcpll_dvfs0_r(), data);
+
+        data = gk20a_readl(g, trim_gpc_bcast_gpcpll_dvfs2_r());
+        udelay(1);
+        data &= ~DFS_EXT_STROBE;
+        gk20a_writel(g, trim_gpc_bcast_gpcpll_dvfs2_r(), data);
+
+        clk_set_dfs_ext_cal(g, d->dfs_ext_cal);
+}
+
+/* Enable NA/DVFS mode */
+static int clk_enbale_pll_dvfs(struct gk20a *g)
+{
+        u32 data;
+        int delay = 5;  /* use for iddq exit delay & calib timeout */
+        struct pll_parms *p = &gpc_pll_params;
+        bool calibrated = p->uvdet_slope && p->uvdet_offs;
+
+        /* FIXME: Set VCO_CTRL */
+
+        /* Enable NA DVFS */
+        data = gk20a_readl(g, trim_sys_gpcpll_dvfs1_r());
+        data |= trim_sys_gpcpll_dvfs1_en_dfs_m();
+        gk20a_writel(g, trim_sys_gpcpll_dvfs1_r(), data);
+
+        /*
+         * If calibration parameters are known (either from fuses, or from
+         * internal calibration on boot) - use them. Internal calibration is
+         * started anyway; it will complete, but results will not be used.
+         */
+        if (calibrated) {
+                data = gk20a_readl(g, trim_sys_gpcpll_dvfs1_r());
+                data |= trim_sys_gpcpll_dvfs1_en_dfs_cal_m();
+                gk20a_writel(g, trim_sys_gpcpll_dvfs1_r(), data);
+        }
+
+        /* Exit IDDQ mode */
+        data = gk20a_readl(g, trim_sys_gpcpll_cfg_r());
+        data = set_field(data, trim_sys_gpcpll_cfg_iddq_m(),
+                         trim_sys_gpcpll_cfg_iddq_power_on_v());
+        gk20a_writel(g, trim_sys_gpcpll_cfg_r(), data);
+        gk20a_readl(g, trim_sys_gpcpll_cfg_r());
+        udelay(delay);
+
+        if (calibrated)
+                return 0;
+
+        /*
+         * If calibration parameters are not fused, start internal calibration,
+         * wait for completion, and use results along with default slope to
+         * calculate ADC offset during boot.
+         */
+        data = gk20a_readl(g, trim_sys_gpcpll_dvfs1_r());
+        data |= trim_sys_gpcpll_dvfs1_en_dfs_cal_m();
+        gk20a_writel(g, trim_sys_gpcpll_dvfs1_r(), data);
+
+        /* Wait for internal calibration done (spec < 2us). */
+        do {
+                data = gk20a_readl(g, trim_sys_gpcpll_dvfs1_r());
+                if (trim_sys_gpcpll_dvfs1_dfs_cal_done_v(data))
+                        break;
+                udelay(1);
+                delay--;
+        } while (delay > 0);
+
+        if (delay <= 0) {
+                gk20a_err(dev_from_gk20a(g), "GPCPLL calibration timeout");
+                return -ETIMEDOUT;
+        }
+
+        data = gk20a_readl(g, trim_sys_gpcpll_cfg3_r());
+        data = trim_sys_gpcpll_cfg3_dfs_testout_v(data);
+        p->uvdet_offs = BOOT_GPU_UV - data * ADC_SLOPE_UV;
+        p->uvdet_slope = ADC_SLOPE_UV;
+        return 0;
+}
+
+/* GPCPLL slide methods */
 static void clk_setup_slide(struct gk20a *g, u32 clk_u)
 {
         u32 data, step_a, step_b;
@@ -320,6 +569,7 @@ static int clk_slide_gpc_pll(struct gk20a *g, struct pll *gpll)
         return 0;
 }
 
+/* GPCPLL bypass methods */
 static int clk_change_pldiv_under_bypass(struct gk20a *g, struct pll *gpll)
 {
         u32 data, coeff;
@@ -381,10 +631,24 @@ static int clk_lock_gpc_pll_under_bypass(struct gk20a *g, struct pll *gpll)
         }
 
         /* change coefficients */
-        coeff = trim_sys_gpcpll_coeff_mdiv_f(gpll->M) |
-                trim_sys_gpcpll_coeff_ndiv_f(gpll->N) |
-                trim_sys_gpcpll_coeff_pldiv_f(gpll->PL);
-        gk20a_writel(g, trim_sys_gpcpll_coeff_r(), coeff);
+        if (gpll->mode == GPC_PLL_MODE_DVFS) {
+                clk_setup_dvfs_detection(g, gpll);
+
+                coeff = gk20a_readl(g, trim_sys_gpcpll_cfg2_r());
+                coeff = set_field(coeff, trim_sys_gpcpll_cfg2_sdm_din_m(),
+                        trim_sys_gpcpll_cfg2_sdm_din_f(gpll->dvfs.sdm_din));
+                gk20a_writel(g, trim_sys_gpcpll_cfg2_r(), coeff);
+
+                coeff = trim_sys_gpcpll_coeff_mdiv_f(gpll->M) |
+                        trim_sys_gpcpll_coeff_ndiv_f(gpll->dvfs.n_int) |
+                        trim_sys_gpcpll_coeff_pldiv_f(gpll->PL);
+                gk20a_writel(g, trim_sys_gpcpll_coeff_r(), coeff);
+        } else {
+                coeff = trim_sys_gpcpll_coeff_mdiv_f(gpll->M) |
+                        trim_sys_gpcpll_coeff_ndiv_f(gpll->N) |
+                        trim_sys_gpcpll_coeff_pldiv_f(gpll->PL);
+                gk20a_writel(g, trim_sys_gpcpll_coeff_r(), coeff);
+        }
 
         /* enable PLL after changing coefficients */
         cfg = gk20a_readl(g, trim_sys_gpcpll_cfg_r());
@@ -392,6 +656,13 @@ static int clk_lock_gpc_pll_under_bypass(struct gk20a *g, struct pll *gpll)
                         trim_sys_gpcpll_cfg_enable_yes_f());
         gk20a_writel(g, trim_sys_gpcpll_cfg_r(), cfg);
 
+        /* just delay in DVFS mode (lock cannot be used) */
+        if (gpll->mode == GPC_PLL_MODE_DVFS) {
+                gk20a_readl(g, trim_sys_gpcpll_cfg_r());
+                udelay(g->clk.na_pll_delay);
+                goto pll_locked;
+        }
+
         /* lock pll */
         cfg = gk20a_readl(g, trim_sys_gpcpll_cfg_r());
         if (cfg & trim_sys_gpcpll_cfg_enb_lckdet_power_off_f()){
@@ -434,6 +705,7 @@ pll_locked:
         return 0;
 }
 
+/* GPCPLL programming in legacy (non-DVFS) mode */
 static int clk_program_gpc_pll(struct gk20a *g, struct pll *gpll_new,
                         int allow_slide)
 {
@@ -549,6 +821,16 @@ set_pldiv:
         return clk_slide_gpc_pll(g, gpll_new);
 }
 
+/* GPCPLL programming in DVFS mode */
+static int clk_program_na_gpc_pll(struct gk20a *g, struct pll *gpll_new,
+                                  int allow_slide)
+{
+        clk_config_dvfs(g, gpll_new);
+
+        /* always under bypass, for now */
+        return clk_program_gpc_pll(g, gpll_new, 0);
+}
+
 static int clk_disable_gpcpll(struct gk20a *g, int allow_slide)
 {
         u32 cfg, coeff;
@@ -617,6 +899,7 @@ static int gm20b_init_clk_setup_sw(struct gk20a *g)
         static int initialized;
         struct clk *ref;
         unsigned long ref_rate;
+        bool calibrated;
 
         gk20a_dbg_fn("");
 
@@ -636,7 +919,14 @@ static int gm20b_init_clk_setup_sw(struct gk20a *g)
         }
         ref_rate = clk_get_rate(ref);
 
+        /*
+         * Locking time in both legacy and DVFS mode is 40us. However, in legacy
+         * mode we rely on lock detection signal, and delay is just timeout
+         * limit, so we can afford set it longer. In DVFS mode each lock inserts
+         * specified delay, so it should be set as short as h/w allows.
+         */
         clk->pll_delay = 300; /* usec */
+        clk->na_pll_delay = 40; /* usec*/
 
         clk->gpc_pll.id = GK20A_GPC_PLL;
         clk->gpc_pll.clk_in = ref_rate / KHZ;
@@ -652,6 +942,17 @@ static int gm20b_init_clk_setup_sw(struct gk20a *g)
                 clk->gpc_pll.freq /= pl_to_div(clk->gpc_pll.PL);
         }
 
+        calibrated = !clk_config_calibration_params(g);
+#ifdef CONFIG_TEGRA_USE_NA_GPCPLL
+        if (ALLOW_NON_CALIBRATED_NA_MODE || calibrated) {
+                /* NA mode is supported only at max update rate 38.4 MHz */
+                if (clk->gpc_pll.clk_in == gpc_pll_params.max_u) {
+                        clk->gpc_pll.mode = GPC_PLL_MODE_DVFS;
+                        gpc_pll_params.min_u = gpc_pll_params.max_u;
+                }
+        }
+#endif
+
         mutex_init(&clk->clk_mutex);
 
         clk->sw_ready = true;
@@ -693,6 +994,9 @@ static int gm20b_init_clk_setup_hw(struct gk20a *g)
         gk20a_writel(g, therm_clk_slowdown_r(0), data);
         gk20a_readl(g, therm_clk_slowdown_r(0));
 
+        if (g->clk.gpc_pll.mode == GPC_PLL_MODE_DVFS)
+                return clk_enbale_pll_dvfs(g);
+
         return 0;
 }
 
@@ -726,9 +1030,15 @@ static int set_pll_freq(struct gk20a *g, int allow_slide)
                      clk->gpc_pll_last.freq, clk->gpc_pll.freq);
 
         /* If programming with dynamic sliding failed, re-try under bypass */
-        err = clk_program_gpc_pll(g, &clk->gpc_pll, allow_slide);
-        if (err && allow_slide)
-                err = clk_program_gpc_pll(g, &clk->gpc_pll, 0);
+        if (clk->gpc_pll.mode == GPC_PLL_MODE_DVFS) {
+                err = clk_program_na_gpc_pll(g, &clk->gpc_pll, allow_slide);
+                if (err && allow_slide)
+                        err = clk_program_na_gpc_pll(g, &clk->gpc_pll, 0);
+        } else {
+                err = clk_program_gpc_pll(g, &clk->gpc_pll, allow_slide);
+                if (err && allow_slide)
+                        err = clk_program_gpc_pll(g, &clk->gpc_pll, 0);
+        }
 
         if (!err) {
                 clk->gpc_pll.enabled = true;