crypto: atmel-sha - add support for Device Tree

Add support for Device Tree and use of the DMA DT API to
get the channels if needed.
Documentation is added for these DT nodes.

Initial code by: Nicolas Royer and Eukrea.

Signed-off-by: Nicolas Ferre <[e-mail]>
Acked-by: Herbert Xu <[e-mail]>

Documentation/devicetree/bindings/crypto/atmel-crypto.txt

···
 	       <&dma1 2 21>;
 	dma-names = "tx", "rx";
 };
+
+* Secure Hash Algorithm (SHA)
+
+Required properties:
+- compatible : Should be "atmel,at91sam9g46-sha".
+- reg: Should contain SHA registers location and length.
+- interrupts: Should contain the IRQ line for the SHA.
+
+Optional properties:
+- dmas: One DMA specifiers as described in
+        atmel-dma.txt and dma.txt files.
+- dma-names: Contains one identifier string for each DMA specifier
+             in the dmas property. Only one "tx" string needed.
+
+Example:
+sha@f8034000 {
+	compatible = "atmel,at91sam9g46-sha";
+	reg = <0xf8034000 0x100>;
+	interrupts = <42 4 0>;
+	dmas = <&dma1 2 17>;
+	dma-names = "tx";
+};

drivers/crypto/atmel-sha.c

···
 #include <linux/irq.h>
 #include <linux/scatterlist.h>
 #include <linux/dma-mapping.h>
+#include <linux/of_device.h>
 #include <linux/delay.h>
 #include <linux/crypto.h>
 #include <linux/cryptohash.h>
···
 	int err = -ENOMEM;
 	dma_cap_mask_t mask_in;
 
-	if (pdata && pdata->dma_slave->rxdata.dma_dev) {
-		/* Try to grab DMA channel */
-		dma_cap_zero(mask_in);
-		dma_cap_set(DMA_SLAVE, mask_in);
+	/* Try to grab DMA channel */
+	dma_cap_zero(mask_in);
+	dma_cap_set(DMA_SLAVE, mask_in);
 
-		dd->dma_lch_in.chan = dma_request_channel(mask_in,
-				atmel_sha_filter, &pdata->dma_slave->rxdata);
-
-		if (!dd->dma_lch_in.chan)
-			return err;
-
-		dd->dma_lch_in.dma_conf.direction = DMA_MEM_TO_DEV;
-		dd->dma_lch_in.dma_conf.dst_addr = dd->phys_base +
-			SHA_REG_DIN(0);
-		dd->dma_lch_in.dma_conf.src_maxburst = 1;
-		dd->dma_lch_in.dma_conf.src_addr_width =
-			DMA_SLAVE_BUSWIDTH_4_BYTES;
-		dd->dma_lch_in.dma_conf.dst_maxburst = 1;
-		dd->dma_lch_in.dma_conf.dst_addr_width =
-			DMA_SLAVE_BUSWIDTH_4_BYTES;
-		dd->dma_lch_in.dma_conf.device_fc = false;
-
-		return 0;
+	dd->dma_lch_in.chan = dma_request_slave_channel_compat(mask_in,
+			atmel_sha_filter, &pdata->dma_slave->rxdata, dd->dev, "tx");
+	if (!dd->dma_lch_in.chan) {
+		dev_warn(dd->dev, "no DMA channel available\n");
+		return err;
 	}
 
-	return -ENODEV;
+	dd->dma_lch_in.dma_conf.direction = DMA_MEM_TO_DEV;
+	dd->dma_lch_in.dma_conf.dst_addr = dd->phys_base +
+		SHA_REG_DIN(0);
+	dd->dma_lch_in.dma_conf.src_maxburst = 1;
+	dd->dma_lch_in.dma_conf.src_addr_width =
+		DMA_SLAVE_BUSWIDTH_4_BYTES;
+	dd->dma_lch_in.dma_conf.dst_maxburst = 1;
+	dd->dma_lch_in.dma_conf.dst_addr_width =
+		DMA_SLAVE_BUSWIDTH_4_BYTES;
+	dd->dma_lch_in.dma_conf.device_fc = false;
+
+	return 0;
 }
 
 static void atmel_sha_dma_cleanup(struct atmel_sha_dev *dd)
···
 		break;
 	}
 }
+
+#if defined(CONFIG_OF)
+static const struct of_device_id atmel_sha_dt_ids[] = {
+	{ .compatible = "atmel,at91sam9g46-sha" },
+	{ /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, atmel_sha_dt_ids);
+
+static struct crypto_platform_data *atmel_sha_of_init(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct crypto_platform_data *pdata;
+
+	if (!np) {
+		dev_err(&pdev->dev, "device node not found\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata) {
+		dev_err(&pdev->dev, "could not allocate memory for pdata\n");
+		return ERR_PTR(-ENOMEM);
+	}
+
+	pdata->dma_slave = devm_kzalloc(&pdev->dev,
+					sizeof(*(pdata->dma_slave)),
+					GFP_KERNEL);
+	if (!pdata->dma_slave) {
+		dev_err(&pdev->dev, "could not allocate memory for dma_slave\n");
+		devm_kfree(&pdev->dev, pdata);
+		return ERR_PTR(-ENOMEM);
+	}
+
+	return pdata;
+}
+#else /* CONFIG_OF */
+static inline struct crypto_platform_data *atmel_sha_of_init(struct platform_device *dev)
+{
+	return ERR_PTR(-EINVAL);
+}
+#endif
 
 static int atmel_sha_probe(struct platform_device *pdev)
 {
···
 	if (sha_dd->caps.has_dma) {
 		pdata = pdev->dev.platform_data;
 		if (!pdata) {
-			dev_err(&pdev->dev, "platform data not available\n");
+			pdata = atmel_sha_of_init(pdev);
+			if (IS_ERR(pdata)) {
+				dev_err(&pdev->dev, "platform data not available\n");
+				err = PTR_ERR(pdata);
+				goto err_pdata;
+			}
+		}
+		if (!pdata->dma_slave) {
 			err = -ENXIO;
 			goto err_pdata;
 		}
 		err = atmel_sha_dma_init(sha_dd, pdata);
 		if (err)
 			goto err_sha_dma;
+
+		dev_info(dev, "using %s for DMA transfers\n",
+				dma_chan_name(sha_dd->dma_lch_in.chan));
 	}
 
 	spin_lock(&atmel_sha.lock);
···
 	.driver		= {
 		.name	= "atmel_sha",
 		.owner	= THIS_MODULE,
+		.of_match_table	= of_match_ptr(atmel_sha_dt_ids),
 	},
 };