ath79: ar934x-nand: add kernel 5.10 compatibility

Adapt the driver to make it work with the NAND subsystem changes between
kernel 5.4 and 5.10.

Tested-on: Aerohive HiveAP121

Signed-off-by: David Bauer <[email protected]>

target/linux/ath79/files/drivers/mtd/nand/raw/ar934x_nand.c

@@ -14,6 +14,9 @@
 #include <linux/module.h>
 #include <linux/dma-mapping.h>
 #include <linux/mtd/mtd.h>
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,9,0)
+#include <linux/mtd/nand.h>
+#endif
 #include <linux/mtd/rawnand.h>
 #include <linux/mtd/partitions.h>
 #include <linux/platform_device.h>
@@ -719,7 +722,11 @@ static void ar934x_nfc_cmdfunc(struct nand_chip *nand, unsigned int command,
 		break;
 
 	case NAND_CMD_PAGEPROG:
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,9,0)
+		if (nand->ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_HOST) {
+#else
 		if (nand->ecc.mode == NAND_ECC_HW) {
+#endif
 			/* the data is already written */
 			break;
 		}
@@ -1325,15 +1332,29 @@ static int ar934x_nfc_attach_chip(struct nand_chip *nand)
 	if (ret)
 		return ret;
 
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,9,0)
+	if (nand->ecc.engine_type == NAND_ECC_ENGINE_TYPE_ON_HOST) {
+#else
 	if (nand->ecc.mode == NAND_ECC_HW) {
+#endif
 		ret = ar934x_nfc_setup_hwecc(nfc);
 		if (ret)
 			return ret;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,9,0)
+	} else if (nand->ecc.engine_type == NAND_ECC_ENGINE_TYPE_SOFT) {
+		dev_err(dev, "unknown ECC mode %d\n", nand->ecc.engine_type);
+#else
 	} else if (nand->ecc.mode != NAND_ECC_SOFT) {
 		dev_err(dev, "unknown ECC mode %d\n", nand->ecc.mode);
+#endif
 		return -EINVAL;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,9,0)
+	} else if ((nand->ecc.algo != NAND_ECC_ALGO_BCH) &&
+		   (nand->ecc.algo != NAND_ECC_ALGO_HAMMING)) {
+#else
 	} else if ((nand->ecc.algo != NAND_ECC_BCH) &&
 		   (nand->ecc.algo != NAND_ECC_HAMMING)) {
+#endif
 		dev_err(dev, "unknown software ECC algo %d\n", nand->ecc.algo);
 		return -EINVAL;
 	}
@@ -1422,7 +1443,11 @@ static int ar934x_nfc_probe(struct platform_device *pdev)
 	nand->legacy.read_byte = ar934x_nfc_read_byte;
 	nand->legacy.write_buf = ar934x_nfc_write_buf;
 	nand->legacy.read_buf = ar934x_nfc_read_buf;
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,9,0)
+	nand->ecc.engine_type = NAND_ECC_ENGINE_TYPE_ON_HOST;	/* default */
+#else
 	nand->ecc.mode = NAND_ECC_HW;	/* default */
+#endif
 	nand->priv = nfc;
 	platform_set_drvdata(pdev, nfc);
 
@@ -1462,7 +1487,12 @@ static int ar934x_nfc_remove(struct platform_device *pdev)
 
 	nfc = platform_get_drvdata(pdev);
 	if (nfc) {
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(5,8,0)
+		mtd_device_unregister(nand_to_mtd(&nfc->nand_chip));
+		nand_cleanup(&nfc->nand_chip);
+#else
 		nand_release(&nfc->nand_chip);
+#endif
 		ar934x_nfc_free_buf(nfc);
 	}