[PATCH 1/4] edac, altera: Generalize driver to use DT Memory size

[tthayer at opensource.altera.com]

From: Thor Thayer <tthayer at opensource.altera.com>

The Arria10 SOC uses a completely different SDRAM controller from the
earlier CycloneV and ArriaV SoCs. The memory size is calculated in
the bootloader and passed via the device tree. Using this device
tree size is more generic than using the register fields to
calculate the memory size for different SDRAM controllers.

Signed-off-by: Thor Thayer <tthayer at opensource.altera.com>
---
 drivers/edac/altera_edac.c |   53 ++++++++++++++++++++++----------------------
 1 file changed, 26 insertions(+), 27 deletions(-)

diff --git a/drivers/edac/altera_edac.c b/drivers/edac/altera_edac.c
index 3c4929f..e18a205 100644
--- a/drivers/edac/altera_edac.c
+++ b/drivers/edac/altera_edac.c
@@ -219,36 +219,35 @@ static void altr_sdr_mc_create_debugfs_nodes(struct mem_ctl_info *mci)
 {}
 #endif
 
-/* Get total memory size in bytes */
-static u32 altr_sdram_get_total_mem_size(struct regmap *mc_vbase)
+/* Get total memory size from Open Firmware DTB */
+static unsigned long get_total_mem(void)
 {
-	u32 size, read_reg, row, bank, col, cs, width;
+	struct device_node *np = NULL;
+	const unsigned int *reg, *reg_end;
+	int len, sw, aw;
+	unsigned long start, size, total_mem;
 
-	if (regmap_read(mc_vbase, DRAMADDRW_OFST, &read_reg) < 0)
+	np = of_find_node_by_type(NULL, "memory");
+	if (!np)
 		return 0;
 
-	if (regmap_read(mc_vbase, DRAMIFWIDTH_OFST, &width) < 0)
-		return 0;
-
-	col = (read_reg & DRAMADDRW_COLBIT_MASK) >>
-		DRAMADDRW_COLBIT_SHIFT;
-	row = (read_reg & DRAMADDRW_ROWBIT_MASK) >>
-		DRAMADDRW_ROWBIT_SHIFT;
-	bank = (read_reg & DRAMADDRW_BANKBIT_MASK) >>
-		DRAMADDRW_BANKBIT_SHIFT;
-	cs = (read_reg & DRAMADDRW_CSBIT_MASK) >>
-		DRAMADDRW_CSBIT_SHIFT;
-
-	/* Correct for ECC as its not addressible */
-	if (width == DRAMIFWIDTH_32B_ECC)
-		width = 32;
-	if (width == DRAMIFWIDTH_16B_ECC)
-		width = 16;
-
-	/* calculate the SDRAM size base on this info */
-	size = 1 << (row + bank + col);
-	size = size * cs * (width / 8);
-	return size;
+	aw = of_n_addr_cells(np);
+	sw = of_n_size_cells(np);
+	reg = (const unsigned int *)of_get_property(np, "reg", &len);
+	reg_end = reg + (len / sizeof(u32));
+
+	total_mem = 0;
+	do {
+		start = of_read_number(reg, aw);
+		reg += aw;
+		size = of_read_number(reg, sw);
+		reg += sw;
+		total_mem += size;
+	} while (reg < reg_end);
+
+	of_node_put(np);
+	edac_printk(KERN_ERR, EDAC_MC, "total_mem 0x%lx\n", total_mem);
+	return total_mem;
 }
 
 static int altr_sdram_probe(struct platform_device *pdev)
@@ -280,7 +279,7 @@ static int altr_sdram_probe(struct platform_device *pdev)
 	}
 
 	/* Grab memory size from device tree. */
-	mem_size = altr_sdram_get_total_mem_size(mc_vbase);
+	mem_size = get_total_mem();
 	if (!mem_size) {
 		edac_printk(KERN_ERR, EDAC_MC,
 			    "Unable to calculate memory size\n");
-- 
1.7.9.5