dmaengine: dw-axi-dmac: move dma_pool_create() to alloc_chan_resources()

The DMA memory block is created at driver load time and exist for
device lifetime. Move the dma_pool_create() to the ->chan_resource()
callback function allowing the DMA memory blocks to be created as needed
and destroyed when the channel is freed.
Signed-off-by: Sia Jee Heng <jee.heng.sia@intel.com>
Tested-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Link: https://lore.kernel.org/r/20210125013255.25799-4-jee.heng.sia@intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/dma/dw-axi-dmac/dw-axi-dmac-platform.c

@@ -216,11 +216,10 @@ static struct axi_dma_desc *axi_desc_alloc(u32 num)
 static struct axi_dma_lli *axi_desc_get(struct axi_dma_chan *chan,
 					dma_addr_t *addr)
 {
-	struct dw_axi_dma *dw = chan->chip->dw;
 	struct axi_dma_lli *lli;
 	dma_addr_t phys;
 
-	lli = dma_pool_zalloc(dw->desc_pool, GFP_NOWAIT, &phys);
+	lli = dma_pool_zalloc(chan->desc_pool, GFP_NOWAIT, &phys);
 	if (unlikely(!lli)) {
 		dev_err(chan2dev(chan), "%s: not enough descriptors available\n",
 			axi_chan_name(chan));
@@ -236,14 +235,13 @@ static struct axi_dma_lli *axi_desc_get(struct axi_dma_chan *chan,
 static void axi_desc_put(struct axi_dma_desc *desc)
 {
 	struct axi_dma_chan *chan = desc->chan;
-	struct dw_axi_dma *dw = chan->chip->dw;
 	int count = atomic_read(&chan->descs_allocated);
 	struct axi_dma_hw_desc *hw_desc;
 	int descs_put;
 
 	for (descs_put = 0; descs_put < count; descs_put++) {
 		hw_desc = &desc->hw_desc[descs_put];
-		dma_pool_free(dw->desc_pool, hw_desc->lli, hw_desc->llp);
+		dma_pool_free(chan->desc_pool, hw_desc->lli, hw_desc->llp);
 	}
 
 	kfree(desc->hw_desc);
@@ -360,6 +358,15 @@ static int dma_chan_alloc_chan_resources(struct dma_chan *dchan)
 		return -EBUSY;
 	}
 
+	/* LLI address must be aligned to a 64-byte boundary */
+	chan->desc_pool = dma_pool_create(dev_name(chan2dev(chan)),
+					  chan->chip->dev,
+					  sizeof(struct axi_dma_lli),
+					  64, 0);
+	if (!chan->desc_pool) {
+		dev_err(chan2dev(chan), "No memory for descriptors\n");
+		return -ENOMEM;
+	}
 	dev_vdbg(dchan2dev(dchan), "%s: allocating\n", axi_chan_name(chan));
 
 	pm_runtime_get(chan->chip->dev);
@@ -381,6 +388,8 @@ static void dma_chan_free_chan_resources(struct dma_chan *dchan)
 
 	vchan_free_chan_resources(&chan->vc);
 
+	dma_pool_destroy(chan->desc_pool);
+	chan->desc_pool = NULL;
 	dev_vdbg(dchan2dev(dchan),
 		 "%s: free resources, descriptor still allocated: %u\n",
 		 axi_chan_name(chan), atomic_read(&chan->descs_allocated));
@@ -896,13 +905,6 @@ static int dw_probe(struct platform_device *pdev)
 	if (ret)
 		return ret;
 
-	/* Lli address must be aligned to a 64-byte boundary */
-	dw->desc_pool = dmam_pool_create(KBUILD_MODNAME, chip->dev,
-					 sizeof(struct axi_dma_lli), 64, 0);
-	if (!dw->desc_pool) {
-		dev_err(chip->dev, "No memory for descriptors dma pool\n");
-		return -ENOMEM;
-	}
 
 	INIT_LIST_HEAD(&dw->dma.channels);
 	for (i = 0; i < hdata->nr_channels; i++) {

drivers/dma/dw-axi-dmac/dw-axi-dmac.h

@@ -39,6 +39,7 @@ struct axi_dma_chan {
 	u8				id;
 	atomic_t			descs_allocated;
 
+	struct dma_pool			*desc_pool;
 	struct virt_dma_chan		vc;
 
 	struct axi_dma_desc		*desc;
@@ -49,7 +50,6 @@ struct axi_dma_chan {
 struct dw_axi_dma {
 	struct dma_device	dma;
 	struct dw_axi_dma_hcfg	*hdata;
-	struct dma_pool		*desc_pool;
 
 	/* channels */
 	struct axi_dma_chan	*chan;