From 46ddf194776500e132693dd2c11b28a971070cc0 Mon Sep 17 00:00:00 2001 From: Ben Widawsky Date: Wed, 12 Sep 2012 18:12:07 -0700 Subject: [PATCH] drm/i915: Add setters for min/max frequency Provide a standardized sysfs interface for setting min, and max frequencies. The code which reads the limits were lifted from the debugfs files. As a brief explanation, the limits are similar to the CPU p-states. We have 3 states: RP0 - ie. max frequency RP1 - ie. "preferred min" frequency RPn - seriously lowest frequency Initially Daniel asked me to clamp the writes to supported values, but in conforming to the way the cpufreq drivers seem to work, instead return -EINVAL (noticed by Jesse in discussion). The values can be used by userspace wishing to control the limits of the GPU (see the CC list for people who care). v4: Make exceeding the soft limits return -EINVAL as well (Daniel) v3: bug fix (Ben) - was passing the MHz value to gen6_set_rps instead of the step value. To fix, deal only with step values by doing the divide at the top. v2: add the dropped mutex_unlock in error cases (Chris) EINVAL on both too min, or too max (Daniel) v2 Reviewed-by: Chris Wilson CC: Daniel Vetter Signed-off-by: Ben Widawsky Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/i915_sysfs.c | 83 ++++++++++++++++++++++++++++++- 1 file changed, 81 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c index 1da07e3e85a..1ffb9880d64 100644 --- a/drivers/gpu/drm/i915/i915_sysfs.c +++ b/drivers/gpu/drm/i915/i915_sysfs.c @@ -238,6 +238,45 @@ static ssize_t gt_max_freq_mhz_show(struct device *kdev, struct device_attribute return snprintf(buf, PAGE_SIZE, "%d", ret); } +static ssize_t gt_max_freq_mhz_store(struct device *kdev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct drm_minor *minor = container_of(kdev, struct drm_minor, kdev); + struct drm_device *dev = minor->dev; + struct drm_i915_private *dev_priv = dev->dev_private; + u32 val, rp_state_cap, hw_max, hw_min; + ssize_t ret; + + ret = kstrtou32(buf, 0, &val); + if (ret) + return ret; + + val /= GT_FREQUENCY_MULTIPLIER; + + ret = mutex_lock_interruptible(&dev->struct_mutex); + if (ret) + return ret; + + rp_state_cap = I915_READ(GEN6_RP_STATE_CAP); + hw_max = (rp_state_cap & 0xff); + hw_min = ((rp_state_cap & 0xff0000) >> 16); + + if (val < hw_min || val > hw_max || val < dev_priv->rps.min_delay) { + mutex_unlock(&dev->struct_mutex); + return -EINVAL; + } + + if (dev_priv->rps.cur_delay > val) + gen6_set_rps(dev_priv->dev, val); + + dev_priv->rps.max_delay = val; + + mutex_unlock(&dev->struct_mutex); + + return count; +} + static ssize_t gt_min_freq_mhz_show(struct device *kdev, struct device_attribute *attr, char *buf) { struct drm_minor *minor = container_of(kdev, struct drm_minor, kdev); @@ -255,9 +294,49 @@ static ssize_t gt_min_freq_mhz_show(struct device *kdev, struct device_attribute return snprintf(buf, PAGE_SIZE, "%d", ret); } +static ssize_t gt_min_freq_mhz_store(struct device *kdev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct drm_minor *minor = container_of(kdev, struct drm_minor, kdev); + struct drm_device *dev = minor->dev; + struct drm_i915_private *dev_priv = dev->dev_private; + u32 val, rp_state_cap, hw_max, hw_min; + ssize_t ret; + + ret = kstrtou32(buf, 0, &val); + if (ret) + return ret; + + val /= GT_FREQUENCY_MULTIPLIER; + + ret = mutex_lock_interruptible(&dev->struct_mutex); + if (ret) + return ret; + + rp_state_cap = I915_READ(GEN6_RP_STATE_CAP); + hw_max = (rp_state_cap & 0xff); + hw_min = ((rp_state_cap & 0xff0000) >> 16); + + if (val < hw_min || val > hw_max || val > dev_priv->rps.max_delay) { + mutex_unlock(&dev->struct_mutex); + return -EINVAL; + } + + if (dev_priv->rps.cur_delay < val) + gen6_set_rps(dev_priv->dev, val); + + dev_priv->rps.min_delay = val; + + mutex_unlock(&dev->struct_mutex); + + return count; + +} + static DEVICE_ATTR(gt_cur_freq_mhz, S_IRUGO, gt_cur_freq_mhz_show, NULL); -static DEVICE_ATTR(gt_max_freq_mhz, S_IRUGO | S_IWUSR, gt_max_freq_mhz_show, NULL); -static DEVICE_ATTR(gt_min_freq_mhz, S_IRUGO | S_IWUSR, gt_min_freq_mhz_show, NULL); +static DEVICE_ATTR(gt_max_freq_mhz, S_IRUGO | S_IWUSR, gt_max_freq_mhz_show, gt_max_freq_mhz_store); +static DEVICE_ATTR(gt_min_freq_mhz, S_IRUGO | S_IWUSR, gt_min_freq_mhz_show, gt_min_freq_mhz_store); static const struct attribute *gen6_attrs[] = { &dev_attr_gt_cur_freq_mhz.attr, -- 2.41.0