intel_mid_dma: Add runtime PM support

This patch adds runtime PM support in this dma driver
for 4 PCI Controllers
Whenever the driver is idle (no channels grabbed), it
can go to low power state
It also adds the PCI suspend and resume support

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

1 files changed, 116 insertions, 7 deletions

diff --git a/drivers/dma/intel_mid_dma.c b/drivers/dma/intel_mid_dma.c
index c2591e8d9b6e..373396c462a0 100644
--- a/drivers/dma/intel_mid_dma.c
+++ b/drivers/dma/intel_mid_dma.c
@@ -25,6 +25,7 @@
  */
 #include <linux/pci.h>
 #include <linux/interrupt.h>
+#include <linux/pm_runtime.h>
 #include <linux/intel_mid_dma.h>
 
 #define MAX_CHAN        4 /*max ch across controllers*/
@@ -247,13 +248,13 @@ static void midc_dostart(struct intel_mid_dma_chan *midc,
         struct middma_device *mid = to_middma_device(midc->chan.device);
 
         /*  channel is idle */
-        if (midc->in_use && test_ch_en(midc->dma_base, midc->ch_id)) {
+        if (midc->busy && test_ch_en(midc->dma_base, midc->ch_id)) {
                 /*error*/
                 pr_err("ERR_MDMA: channel is busy in start\n");
                 /* The tasklet will hopefully advance the queue... */
                 return;
         }
-
+        midc->busy = true;
         /*write registers and en*/
         iowrite32(first->sar, midc->ch_regs + SAR);
         iowrite32(first->dar, midc->ch_regs + DAR);
@@ -290,7 +291,7 @@ static void midc_descriptor_complete(struct intel_mid_dma_chan *midc,
         param_txd = txd->callback_param;
 
         list_move(&desc->desc_node, &midc->free_list);
-
+        midc->busy = false;
         spin_unlock_bh(&midc->lock);
         if (callback_txd) {
                 pr_debug("MDMA: TXD callback set ... calling\n");
@@ -434,7 +435,7 @@ static int intel_mid_dma_device_control(struct dma_chan *chan,
                 return -ENXIO;
 
         spin_lock_bh(&midc->lock);
-        if (midc->in_use == false) {
+        if (midc->busy == false) {
                 spin_unlock_bh(&midc->lock);
                 return 0;
         }
@@ -618,11 +619,11 @@ static void intel_mid_dma_free_chan_resources(struct dma_chan *chan)
         struct middma_device    *mid = to_middma_device(chan->device);
         struct intel_mid_dma_desc       *desc, *_desc;
 
-        if (true == midc->in_use) {
+        if (true == midc->busy) {
                 /*trying to free ch in use!!!!!*/
                 pr_err("ERR_MDMA: trying to free ch in use\n");
         }
-
+        pm_runtime_put(&mid->pdev->dev);
         spin_lock_bh(&midc->lock);
         midc->descs_allocated = 0;
         list_for_each_entry_safe(desc, _desc, &midc->active_list, desc_node) {
@@ -639,6 +640,7 @@ static void intel_mid_dma_free_chan_resources(struct dma_chan *chan)
         }
         spin_unlock_bh(&midc->lock);
         midc->in_use = false;
+        midc->busy = false;
         /* Disable CH interrupts */
         iowrite32(MASK_INTR_REG(midc->ch_id), mid->dma_base + MASK_BLOCK);
         iowrite32(MASK_INTR_REG(midc->ch_id), mid->dma_base + MASK_ERR);
@@ -659,11 +661,20 @@ static int intel_mid_dma_alloc_chan_resources(struct dma_chan *chan)
         dma_addr_t              phys;
         int     i = 0;
 
+        pm_runtime_get_sync(&mid->pdev->dev);
+
+        if (mid->state == SUSPENDED) {
+                if (dma_resume(mid->pdev)) {
+                        pr_err("ERR_MDMA: resume failed");
+                        return -EFAULT;
+                }
+        }
 
         /* ASSERT:  channel is idle */
         if (test_ch_en(mid->dma_base, midc->ch_id)) {
                 /*ch is not idle*/
                 pr_err("ERR_MDMA: ch not idle\n");
+                pm_runtime_put(&mid->pdev->dev);
                 return -EIO;
         }
         midc->completed = chan->cookie = 1;
@@ -674,6 +685,7 @@ static int intel_mid_dma_alloc_chan_resources(struct dma_chan *chan)
                 desc = pci_pool_alloc(mid->dma_pool, GFP_KERNEL, &phys);
                 if (!desc) {
                         pr_err("ERR_MDMA: desc failed\n");
+                        pm_runtime_put(&mid->pdev->dev);
                         return -ENOMEM;
                         /*check*/
                 }
@@ -686,7 +698,8 @@ static int intel_mid_dma_alloc_chan_resources(struct dma_chan *chan)
                 list_add_tail(&desc->desc_node, &midc->free_list);
         }
         spin_unlock_bh(&midc->lock);
-        midc->in_use = false;
+        midc->in_use = true;
+        midc->busy = false;
         pr_debug("MID_DMA: Desc alloc done ret: %d desc\n", i);
         return i;
 }
@@ -884,6 +897,7 @@ static int mid_setup_dma(struct pci_dev *pdev)
         pr_debug("MDMA:Adding %d channel for this controller\n", dma->max_chan);
         /*init CH structures*/
         dma->intr_mask = 0;
+        dma->state = RUNNING;
         for (i = 0; i < dma->max_chan; i++) {
                 struct intel_mid_dma_chan *midch = &dma->ch[i];
 
@@ -1070,6 +1084,9 @@ static int __devinit intel_mid_dma_probe(struct pci_dev *pdev,
         if (err)
                 goto err_dma;
 
+        pm_runtime_set_active(&pdev->dev);
+        pm_runtime_enable(&pdev->dev);
+        pm_runtime_allow(&pdev->dev);
         return 0;
 
 err_dma:
@@ -1104,6 +1121,85 @@ static void __devexit intel_mid_dma_remove(struct pci_dev *pdev)
         pci_disable_device(pdev);
 }
 
+/* Power Management */
+/*
+* dma_suspend - PCI suspend function
+*
+* @pci: PCI device structure
+* @state: PM message
+*
+* This function is called by OS when a power event occurs
+*/
+int dma_suspend(struct pci_dev *pci, pm_message_t state)
+{
+        int i;
+        struct middma_device *device = pci_get_drvdata(pci);
+        pr_debug("MDMA: dma_suspend called\n");
+
+        for (i = 0; i < device->max_chan; i++) {
+                if (device->ch[i].in_use)
+                        return -EAGAIN;
+        }
+        device->state = SUSPENDED;
+        pci_set_drvdata(pci, device);
+        pci_save_state(pci);
+        pci_disable_device(pci);
+        pci_set_power_state(pci, PCI_D3hot);
+        return 0;
+}
+
+/**
+* dma_resume - PCI resume function
+*
+* @pci: PCI device structure
+*
+* This function is called by OS when a power event occurs
+*/
+int dma_resume(struct pci_dev *pci)
+{
+        int ret;
+        struct middma_device *device = pci_get_drvdata(pci);
+
+        pr_debug("MDMA: dma_resume called\n");
+        pci_set_power_state(pci, PCI_D0);
+        pci_restore_state(pci);
+        ret = pci_enable_device(pci);
+        if (ret) {
+                pr_err("MDMA: device cant be enabled for %x\n", pci->device);
+                return ret;
+        }
+        device->state = RUNNING;
+        iowrite32(REG_BIT0, device->dma_base + DMA_CFG);
+        pci_set_drvdata(pci, device);
+        return 0;
+}
+
+static int dma_runtime_suspend(struct device *dev)
+{
+        struct pci_dev *pci_dev = to_pci_dev(dev);
+        return dma_suspend(pci_dev, PMSG_SUSPEND);
+}
+
+static int dma_runtime_resume(struct device *dev)
+{
+        struct pci_dev *pci_dev = to_pci_dev(dev);
+        return dma_resume(pci_dev);
+}
+
+static int dma_runtime_idle(struct device *dev)
+{
+        struct pci_dev *pdev = to_pci_dev(dev);
+        struct middma_device *device = pci_get_drvdata(pdev);
+        int i;
+
+        for (i = 0; i < device->max_chan; i++) {
+                if (device->ch[i].in_use)
+                        return -EAGAIN;
+        }
+
+        return pm_schedule_suspend(dev, 0);
+}
+
 /******************************************************************************
 * PCI stuff
 */
@@ -1116,11 +1212,24 @@ static struct pci_device_id intel_mid_dma_ids[] = {
 };
 MODULE_DEVICE_TABLE(pci, intel_mid_dma_ids);
 
+static const struct dev_pm_ops intel_mid_dma_pm = {
+        .runtime_suspend = dma_runtime_suspend,
+        .runtime_resume = dma_runtime_resume,
+        .runtime_idle = dma_runtime_idle,
+};
+
 static struct pci_driver intel_mid_dma_pci = {
         .name           =       "Intel MID DMA",
         .id_table       =       intel_mid_dma_ids,
         .probe          =       intel_mid_dma_probe,
         .remove         =       __devexit_p(intel_mid_dma_remove),
+#ifdef CONFIG_PM
+        .suspend = dma_suspend,
+        .resume = dma_resume,
+        .driver = {
+                .pm = &intel_mid_dma_pm,
+        },
+#endif
 };
 
 static int __init intel_mid_dma_init(void)