Revert "mvebu: remove linux 4.4 support"

This reverts commit 51397d7d95d9f5e210a5557f65de1fa21e6f5921.
There are some unresolved random crashes on WRT1900AC v1 that still need
to be sorted out

Signed-off-by: Felix Fietkau <nbd@nbd.name>

1 files changed, 104 insertions, 0 deletions

diff --git a/target/linux/mvebu/patches-4.4/022-mtd-pxa3xx_nand-Fix-initial-controller-configuration.patch b/target/linux/mvebu/patches-4.4/022-mtd-pxa3xx_nand-Fix-initial-controller-configuration.patch
new file mode 100644
index 0000000000..7d07fb9423
--- /dev/null
+++ b/target/linux/mvebu/patches-4.4/022-mtd-pxa3xx_nand-Fix-initial-controller-configuration.patch
@@ -0,0 +1,104 @@
+From: =?UTF-8?q?Ezequiel=20Garc=C3=ADa?= <ezequiel@vanguardiasur.com.ar>
+Date: Wed, 4 Nov 2015 13:13:42 -0300
+Subject: [PATCH] mtd: pxa3xx_nand: Fix initial controller configuration
+
+The Data Flash Control Register (NDCR) contains two types
+of parameters: those that are needed for device identification,
+and those that can only be set after device identification.
+
+Therefore, the driver can't set them all at once and instead
+needs to configure the first group before nand_scan_ident()
+and the second group later.
+
+Let's split pxa3xx_nand_config in two halves, and set the
+parameters that depend on the device geometry once this is known.
+
+Signed-off-by: Ezequiel Garcia <ezequiel@vanguardiasur.com.ar>
+Signed-off-by: Brian Norris <computersforpeace@gmail.com>
+---
+
+--- a/drivers/mtd/nand/pxa3xx_nand.c
++++ b/drivers/mtd/nand/pxa3xx_nand.c
+@@ -1420,34 +1420,43 @@ static int pxa3xx_nand_waitfunc(struct m
+ 	return NAND_STATUS_READY;
+ }
+ 
+-static int pxa3xx_nand_config_flash(struct pxa3xx_nand_info *info)
++static int pxa3xx_nand_config_ident(struct pxa3xx_nand_info *info)
+ {
+ 	struct platform_device *pdev = info->pdev;
+ 	struct pxa3xx_nand_platform_data *pdata = dev_get_platdata(&pdev->dev);
+-	struct pxa3xx_nand_host *host = info->host[info->cs];
+-	struct mtd_info *mtd = host->mtd;
+-	struct nand_chip *chip = mtd->priv;
+ 
+-	/* configure default flash values */
++	/* Configure default flash values */
++	info->chunk_size = PAGE_CHUNK_SIZE;
+ 	info->reg_ndcr = 0x0; /* enable all interrupts */
+ 	info->reg_ndcr |= (pdata->enable_arbiter) ? NDCR_ND_ARB_EN : 0;
+ 	info->reg_ndcr |= NDCR_RD_ID_CNT(READ_ID_BYTES);
+-	info->reg_ndcr |= NDCR_SPARE_EN; /* enable spare by default */
++	info->reg_ndcr |= NDCR_SPARE_EN;
++
++	return 0;
++}
++
++static void pxa3xx_nand_config_tail(struct pxa3xx_nand_info *info)
++{
++	struct pxa3xx_nand_host *host = info->host[info->cs];
++	struct mtd_info *mtd = host->mtd;
++	struct nand_chip *chip = mtd->priv;
++
+ 	info->reg_ndcr |= (host->col_addr_cycles == 2) ? NDCR_RA_START : 0;
+ 	info->reg_ndcr |= (chip->page_shift == 6) ? NDCR_PG_PER_BLK : 0;
+ 	info->reg_ndcr |= (mtd->writesize == 2048) ? NDCR_PAGE_SZ : 0;
+-
+-	return 0;
+ }
+ 
+ static int pxa3xx_nand_detect_config(struct pxa3xx_nand_info *info)
+ {
++	struct platform_device *pdev = info->pdev;
++	struct pxa3xx_nand_platform_data *pdata = dev_get_platdata(&pdev->dev);
+ 	uint32_t ndcr = nand_readl(info, NDCR);
+ 
+ 	/* Set an initial chunk size */
+ 	info->chunk_size = ndcr & NDCR_PAGE_SZ ? 2048 : 512;
+ 	info->reg_ndcr = ndcr &
+ 		~(NDCR_INT_MASK | NDCR_ND_ARB_EN | NFCV1_NDCR_ARB_CNTL);
++	info->reg_ndcr |= (pdata->enable_arbiter) ? NDCR_ND_ARB_EN : 0;
+ 	info->ndtr0cs0 = nand_readl(info, NDTR0CS0);
+ 	info->ndtr1cs0 = nand_readl(info, NDTR1CS0);
+ 	return 0;
+@@ -1636,10 +1645,7 @@ static int pxa3xx_nand_scan(struct mtd_i
+ 	if (pdata->keep_config && !pxa3xx_nand_detect_config(info))
+ 		goto KEEP_CONFIG;
+ 
+-	/* Set a default chunk size */
+-	info->chunk_size = PAGE_CHUNK_SIZE;
+-
+-	ret = pxa3xx_nand_config_flash(info);
++	ret = pxa3xx_nand_config_ident(info);
+ 	if (ret)
+ 		return ret;
+ 
+@@ -1652,7 +1658,6 @@ static int pxa3xx_nand_scan(struct mtd_i
+ 	}
+ 
+ KEEP_CONFIG:
+-	info->reg_ndcr |= (pdata->enable_arbiter) ? NDCR_ND_ARB_EN : 0;
+ 	if (info->reg_ndcr & NDCR_DWIDTH_M)
+ 		chip->options |= NAND_BUSWIDTH_16;
+ 
+@@ -1737,6 +1742,10 @@ KEEP_CONFIG:
+ 		host->row_addr_cycles = 3;
+ 	else
+ 		host->row_addr_cycles = 2;
++
++	if (!pdata->keep_config)
++		pxa3xx_nand_config_tail(info);
++
+ 	return nand_scan_tail(mtd);
+ }
+