crypto: atmel-aes - add support for Device Tree

Add support for Device Tree and use of the DMA DT API to
get the needed channels.
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

···
+* Atmel HW cryptographic accelerators
+
+These are the HW cryptographic accelerators found on some Atmel products.
+
+* Advanced Encryption Standard (AES)
+
+Required properties:
+- compatible : Should be "atmel,at91sam9g46-aes".
+- reg: Should contain AES registers location and length.
+- interrupts: Should contain the IRQ line for the AES.
+- dmas: List of two 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.
+
+Example:
+aes@f8038000 {
+	compatible = "atmel,at91sam9g46-aes";
+	reg = <0xf8038000 0x100>;
+	interrupts = <43 4 0>;
+	dmas = <&dma1 2 18>,
+	       <&dma1 2 19>;
+	dma-names = "tx", "rx";

drivers/crypto/atmel-aes.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>
···
 #include <crypto/hash.h>
 #include <crypto/internal/hash.h>
 #include <linux/platform_data/crypto-atmel.h>
+#include <dt-bindings/dma/at91.h>
 #include "atmel-aes-regs.h"
 
 #define CFB8_BLOCK_SIZE		1
···
 	struct crypto_platform_data *pdata)
 {
 	int err = -ENOMEM;
-	dma_cap_mask_t mask_in, mask_out;
+	dma_cap_mask_t mask;
 
-	if (pdata && pdata->dma_slave->txdata.dma_dev &&
-		pdata->dma_slave->rxdata.dma_dev) {
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
 
-		/* Try to grab 2 DMA channels */
-		dma_cap_zero(mask_in);
-		dma_cap_set(DMA_SLAVE, mask_in);
+	/* Try to grab 2 DMA channels */
+	dd->dma_lch_in.chan = dma_request_slave_channel_compat(mask,
+			atmel_aes_filter, &pdata->dma_slave->rxdata, dd->dev, "tx");
+	if (!dd->dma_lch_in.chan)
+		goto err_dma_in;
 
-		dd->dma_lch_in.chan = dma_request_channel(mask_in,
-				atmel_aes_filter, &pdata->dma_slave->rxdata);
+	dd->dma_lch_in.dma_conf.direction = DMA_MEM_TO_DEV;
+	dd->dma_lch_in.dma_conf.dst_addr = dd->phys_base +
+		AES_IDATAR(0);
+	dd->dma_lch_in.dma_conf.src_maxburst = dd->caps.max_burst_size;
+	dd->dma_lch_in.dma_conf.src_addr_width =
+		DMA_SLAVE_BUSWIDTH_4_BYTES;
+	dd->dma_lch_in.dma_conf.dst_maxburst = dd->caps.max_burst_size;
+	dd->dma_lch_in.dma_conf.dst_addr_width =
+		DMA_SLAVE_BUSWIDTH_4_BYTES;
+	dd->dma_lch_in.dma_conf.device_fc = false;
 
-		if (!dd->dma_lch_in.chan)
-			goto err_dma_in;
+	dd->dma_lch_out.chan = dma_request_slave_channel_compat(mask,
+			atmel_aes_filter, &pdata->dma_slave->txdata, dd->dev, "rx");
+	if (!dd->dma_lch_out.chan)
+		goto err_dma_out;
 
-		dd->dma_lch_in.dma_conf.direction = DMA_MEM_TO_DEV;
-		dd->dma_lch_in.dma_conf.dst_addr = dd->phys_base +
-			AES_IDATAR(0);
-		dd->dma_lch_in.dma_conf.src_maxburst = dd->caps.max_burst_size;
-		dd->dma_lch_in.dma_conf.src_addr_width =
-			DMA_SLAVE_BUSWIDTH_4_BYTES;
-		dd->dma_lch_in.dma_conf.dst_maxburst = dd->caps.max_burst_size;
-		dd->dma_lch_in.dma_conf.dst_addr_width =
-			DMA_SLAVE_BUSWIDTH_4_BYTES;
-		dd->dma_lch_in.dma_conf.device_fc = false;
+	dd->dma_lch_out.dma_conf.direction = DMA_DEV_TO_MEM;
+	dd->dma_lch_out.dma_conf.src_addr = dd->phys_base +
+		AES_ODATAR(0);
+	dd->dma_lch_out.dma_conf.src_maxburst = dd->caps.max_burst_size;
+	dd->dma_lch_out.dma_conf.src_addr_width =
+		DMA_SLAVE_BUSWIDTH_4_BYTES;
+	dd->dma_lch_out.dma_conf.dst_maxburst = dd->caps.max_burst_size;
+	dd->dma_lch_out.dma_conf.dst_addr_width =
+		DMA_SLAVE_BUSWIDTH_4_BYTES;
+	dd->dma_lch_out.dma_conf.device_fc = false;
 
-		dma_cap_zero(mask_out);
-		dma_cap_set(DMA_SLAVE, mask_out);
-		dd->dma_lch_out.chan = dma_request_channel(mask_out,
-				atmel_aes_filter, &pdata->dma_slave->txdata);
-
-		if (!dd->dma_lch_out.chan)
-			goto err_dma_out;
-
-		dd->dma_lch_out.dma_conf.direction = DMA_DEV_TO_MEM;
-		dd->dma_lch_out.dma_conf.src_addr = dd->phys_base +
-			AES_ODATAR(0);
-		dd->dma_lch_out.dma_conf.src_maxburst = dd->caps.max_burst_size;
-		dd->dma_lch_out.dma_conf.src_addr_width =
-			DMA_SLAVE_BUSWIDTH_4_BYTES;
-		dd->dma_lch_out.dma_conf.dst_maxburst = dd->caps.max_burst_size;
-		dd->dma_lch_out.dma_conf.dst_addr_width =
-			DMA_SLAVE_BUSWIDTH_4_BYTES;
-		dd->dma_lch_out.dma_conf.device_fc = false;
-
-		return 0;
-	} else {
-		return -ENODEV;
-	}
+	return 0;
 
 err_dma_out:
 	dma_release_channel(dd->dma_lch_in.chan);
 err_dma_in:
+	dev_warn(dd->dev, "no DMA channel available\n");
 	return err;
 }
 
···
 	}
 }
 
+#if defined(CONFIG_OF)
+static const struct of_device_id atmel_aes_dt_ids[] = {
+	{ .compatible = "atmel,at91sam9g46-aes" },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, atmel_aes_dt_ids);
+
+static struct crypto_platform_data *atmel_aes_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
+static inline struct crypto_platform_data *atmel_aes_of_init(struct platform_device *pdev)
+{
+	return ERR_PTR(-EINVAL);
+}
+#endif
+
 static int atmel_aes_probe(struct platform_device *pdev)
 {
 	struct atmel_aes_dev *aes_dd;
···
 
 	pdata = pdev->dev.platform_data;
 	if (!pdata) {
+		pdata = atmel_aes_of_init(pdev);
+		if (IS_ERR(pdata)) {
+			err = PTR_ERR(pdata);
+			goto aes_dd_err;
+		}
+	}
+
+	if (!pdata->dma_slave) {
 		err = -ENXIO;
 		goto aes_dd_err;
 	}
···
 	if (err)
 		goto err_algs;
 
-	dev_info(dev, "Atmel AES\n");
+	dev_info(dev, "Atmel AES - Using %s, %s for DMA transfers\n",
+			dma_chan_name(aes_dd->dma_lch_in.chan),
+			dma_chan_name(aes_dd->dma_lch_out.chan));
 
 	return 0;
 
···
 	.driver		= {
 		.name	= "atmel_aes",
 		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(atmel_aes_dt_ids),
 	},
 };