[Intel-gfx] [RFC 1/1] drm/i915 : Wait until SYSTEM_RUNNING before loading CSR firmware

[jay.p.patel at intel.com]

From: Jay Patel <jay.p.patel at intel.com>

NOTE: This is an interim solution which is targeted towards
Chrome OS/Android to be used until a long term solution is available.

In this patch, request_firmware() is called in a worker thread
which initially waits for file system to be initialized and then
attempts to load the firmware.

"request_firmware_nowait()" is also using an asynchronous thread
running concurrently with the rest of the system initialization.
However, it tries to load firmware only once without checking the
sytem status and fails most of the time.

Change-Id: I2cb16a768e54a85f48a6682d9690b4c8af844668
Signed-off-by: Jay Patel <jay.p.patel at intel.com>
---
 drivers/gpu/drm/i915/i915_drv.c  |  2 ++
 drivers/gpu/drm/i915/intel_csr.c | 58 ++++++++++++++++++++++++++++++++--------
 2 files changed, 49 insertions(+), 11 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 8c8407d..eb6f7e3 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -559,6 +559,7 @@ void intel_hpd_cancel_work(struct drm_i915_private *dev_priv)
 void i915_firmware_load_error_print(const char *fw_path, int err)
 {
 	DRM_ERROR("failed to load firmware %s (%d)\n", fw_path, err);
+	DRM_ERROR("The firmware file may be missing\n");
 
 	/*
 	 * If the reason is not known assume -ENOENT since that's the most
@@ -574,6 +575,7 @@ void i915_firmware_load_error_print(const char *fw_path, int err)
 	  "The driver is built-in, so to load the firmware you need to\n"
 	  "include it either in the kernel (see CONFIG_EXTRA_FIRMWARE) or\n"
 	  "in your initrd/initramfs image.\n");
+
 }
 
 static void intel_suspend_encoders(struct drm_i915_private *dev_priv)
diff --git a/drivers/gpu/drm/i915/intel_csr.c b/drivers/gpu/drm/i915/intel_csr.c
index 9311cdd..8d1f08c 100644
--- a/drivers/gpu/drm/i915/intel_csr.c
+++ b/drivers/gpu/drm/i915/intel_csr.c
@@ -349,7 +349,7 @@ static void finish_csr_load(const struct firmware *fw, void *context)
 	/* load csr program during system boot, as needed for DC states */
 	intel_csr_load_program(dev);
 	fw_loaded = true;
-
+	DRM_INFO("CSR Firmware Loaded\n");
 out:
 	if (fw_loaded)
 		intel_runtime_pm_put(dev_priv);
@@ -359,11 +359,46 @@ out:
 	release_firmware(fw);
 }
 
+struct csr_firmware_work {
+	struct work_struct work;
+	struct module *module;
+	struct drm_device *dev;
+};
+
+/* csr_firmware_work_func() - thread function for loading the firmware*/
+static void csr_firmware_work_func(struct work_struct *work)
+{
+	const struct firmware *fw;
+	const struct csr_firmware_work *fw_work = container_of(work, struct csr_firmware_work, work);
+	int ret;
+	struct drm_device *dev = fw_work->dev;
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	struct intel_csr *csr = &dev_priv->csr;
+
+	/* Wait until root filesystem is loaded in case the firmware
+	 * is not built-in but in /lib/firmware */
+	while(system_state !=  SYSTEM_RUNNING){
+		msleep(500);
+	}
+
+	ret = request_firmware(&fw, csr->fw_path, &dev_priv->dev->pdev->dev);
+        if (ret) {
+		i915_firmware_load_error_print(csr->fw_path, ret);
+		intel_csr_load_status_set(dev_priv, FW_FAILED);
+	} else {
+		finish_csr_load(fw, dev_priv);
+		put_device(&dev_priv->dev->pdev->dev);
+		module_put(fw_work->module);
+	}
+
+	kfree(fw_work);
+}
+
 void intel_csr_ucode_init(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct intel_csr *csr = &dev_priv->csr;
-	int ret;
+	struct csr_firmware_work *fw_work;
 
 	if (!HAS_CSR(dev))
 		return;
@@ -382,15 +417,16 @@ void intel_csr_ucode_init(struct drm_device *dev)
 	 */
 	intel_runtime_pm_get(dev_priv);
 
-	/* CSR supported for platform, load firmware */
-	ret = request_firmware_nowait(THIS_MODULE, true, csr->fw_path,
-				&dev_priv->dev->pdev->dev,
-				GFP_KERNEL, dev_priv,
-				finish_csr_load);
-	if (ret) {
-		i915_firmware_load_error_print(csr->fw_path, ret);
-		intel_csr_load_status_set(dev_priv, FW_FAILED);
-	}
+	/* Creating a thread which loads firmware */
+	fw_work = kzalloc(sizeof(struct csr_firmware_work), GFP_KERNEL);
+        if (!fw_work) {
+                return;
+        }
+	fw_work->module = THIS_MODULE;
+	fw_work->dev = dev;
+	INIT_WORK(&fw_work->work, csr_firmware_work_func);
+	schedule_work(&fw_work->work);
+	DRM_DEBUG("CSR firmware loader thread started \n");
 }
 
 void intel_csr_ucode_fini(struct drm_device *dev)
-- 
2.1.2