ASoC: SOF: Intel: hda: add a parameter to disable MSI

Enabling MSI on HDA can fail, in which case the legacy PCI IRQ mode
will be used. To make testing this mode easier add an "enable_msi"
module parameter, which is only enabled if debugging is enabled too.

Signed-off-by: Guennadi Liakhovetski <guennadi.liakhovetski@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190722141402.7194-17-pierre-louis.bossart@linux.intel.com
Signed-off-by: Mark Brown <broonie@kernel.org>

2 files changed, 18 insertions, 12 deletions

diff --git a/sound/soc/sof/intel/hda.c b/sound/soc/sof/intel/hda.c
index 7f665392618f..79cce20666b6 100644
--- a/sound/soc/sof/intel/hda.c
+++ b/sound/soc/sof/intel/hda.c
@@ -46,6 +46,12 @@ struct hda_dsp_msg_code {
         const char *msg;
 };
 
+static bool hda_use_msi = IS_ENABLED(CONFIG_PCI);
+#if IS_ENABLED(CONFIG_SND_SOC_SOF_DEBUG)
+module_param_named(use_msi, hda_use_msi, bool, 0444);
+MODULE_PARM_DESC(use_msi, "SOF HDA use PCI MSI mode");
+#endif
+
 static const struct hda_dsp_msg_code hda_dsp_rom_msg[] = {
         {HDA_DSP_ROM_FW_MANIFEST_LOADED, "status: manifest loaded"},
         {HDA_DSP_ROM_FW_FW_LOADED, "status: fw loaded"},
@@ -529,11 +535,18 @@ int hda_dsp_probe(struct snd_sof_dev *sdev)
          * register our IRQ
          * let's try to enable msi firstly
          * if it fails, use legacy interrupt mode
-         * TODO: support interrupt mode selection with kernel parameter
-         *       support msi multiple vectors
+         * TODO: support msi multiple vectors
          */
-        ret = pci_alloc_irq_vectors(pci, 1, 1, PCI_IRQ_MSI);
-        if (ret < 0) {
+        if (hda_use_msi && !pci_alloc_irq_vectors(pci, 1, 1, PCI_IRQ_MSI)) {
+                dev_info(sdev->dev, "use msi interrupt mode\n");
+                hdev->irq = pci_irq_vector(pci, 0);
+                /* ipc irq number is the same of hda irq */
+                sdev->ipc_irq = hdev->irq;
+                /* initialised to "false" by kzalloc() */
+                sdev->msi_enabled = true;
+        }
+
+        if (!sdev->msi_enabled) {
                 dev_info(sdev->dev, "use legacy interrupt mode\n");
                 /*
                  * in IO-APIC mode, hda->irq and ipc_irq are using the same
@@ -541,13 +554,6 @@ int hda_dsp_probe(struct snd_sof_dev *sdev)
                  */
                 hdev->irq = pci->irq;
                 sdev->ipc_irq = pci->irq;
-                sdev->msi_enabled = 0;
-        } else {
-                dev_info(sdev->dev, "use msi interrupt mode\n");
-                hdev->irq = pci_irq_vector(pci, 0);
-                /* ipc irq number is the same of hda irq */
-                sdev->ipc_irq = hdev->irq;
-                sdev->msi_enabled = 1;
         }
 
         dev_dbg(sdev->dev, "using HDA IRQ %d\n", hdev->irq);
diff --git a/sound/soc/sof/sof-priv.h b/sound/soc/sof/sof-priv.h
index b8c9274ccf42..983eadef4b30 100644
--- a/sound/soc/sof/sof-priv.h
+++ b/sound/soc/sof/sof-priv.h
@@ -435,7 +435,7 @@ struct snd_sof_dev {
         u32 dtrace_error;
         u32 dtrace_draining;
 
-        u32 msi_enabled;
+        bool msi_enabled;
 
         void *private;                  /* core does not touch this */
 };