Merge tag 'tegra-for-4.2-emc' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux into next/drivers

Merge "ARM: tegra: Add EMC driver for v4.2-rc1" from Thierry Reding:

This introduces the EMC driver that's required to scale the external
memory frequency.

* tag 'tegra-for-4.2-emc' of git://git.kernel.org/pub/scm/linux/kernel/git/tegra/linux:
  memory: tegra: Add EMC frequency debugfs entry
  memory: tegra: Add EMC (external memory controller) driver
  memory: tegra: Add API needed by the EMC driver
  of: Add Tegra124 EMC bindings
  of: Document timings subnode of nvidia,tegra-mc

drivers/memory/tegra/mc.c

@@ -13,6 +13,9 @@
 #include <linux/of.h>
 #include <linux/platform_device.h>
 #include <linux/slab.h>
+#include <linux/sort.h>
+
+#include <soc/tegra/fuse.h>
 
 #include "mc.h"
 
@@ -48,6 +51,9 @@
 #define  MC_EMEM_ARB_CFG_CYCLES_PER_UPDATE_MASK	0x1ff
 #define MC_EMEM_ARB_MISC0 0xd8
 
+#define MC_EMEM_ADR_CFG 0x54
+#define MC_EMEM_ADR_CFG_EMEM_NUMDEV BIT(0)
+
 static const struct of_device_id tegra_mc_of_match[] = {
 #ifdef CONFIG_ARCH_TEGRA_3x_SOC
 	{ .compatible = "nvidia,tegra30-mc", .data = &tegra30_mc_soc },
@@ -94,6 +100,130 @@ static int tegra_mc_setup_latency_allowance(struct tegra_mc *mc)
 	return 0;
 }
 
+void tegra_mc_write_emem_configuration(struct tegra_mc *mc, unsigned long rate)
+{
+	unsigned int i;
+	struct tegra_mc_timing *timing = NULL;
+
+	for (i = 0; i < mc->num_timings; i++) {
+		if (mc->timings[i].rate == rate) {
+			timing = &mc->timings[i];
+			break;
+		}
+	}
+
+	if (!timing) {
+		dev_err(mc->dev, "no memory timing registered for rate %lu\n",
+			rate);
+		return;
+	}
+
+	for (i = 0; i < mc->soc->num_emem_regs; ++i)
+		mc_writel(mc, timing->emem_data[i], mc->soc->emem_regs[i]);
+}
+
+unsigned int tegra_mc_get_emem_device_count(struct tegra_mc *mc)
+{
+	u8 dram_count;
+
+	dram_count = mc_readl(mc, MC_EMEM_ADR_CFG);
+	dram_count &= MC_EMEM_ADR_CFG_EMEM_NUMDEV;
+	dram_count++;
+
+	return dram_count;
+}
+
+static int load_one_timing(struct tegra_mc *mc,
+			   struct tegra_mc_timing *timing,
+			   struct device_node *node)
+{
+	int err;
+	u32 tmp;
+
+	err = of_property_read_u32(node, "clock-frequency", &tmp);
+	if (err) {
+		dev_err(mc->dev,
+			"timing %s: failed to read rate\n", node->name);
+		return err;
+	}
+
+	timing->rate = tmp;
+	timing->emem_data = devm_kcalloc(mc->dev, mc->soc->num_emem_regs,
+					 sizeof(u32), GFP_KERNEL);
+	if (!timing->emem_data)
+		return -ENOMEM;
+
+	err = of_property_read_u32_array(node, "nvidia,emem-configuration",
+					 timing->emem_data,
+					 mc->soc->num_emem_regs);
+	if (err) {
+		dev_err(mc->dev,
+			"timing %s: failed to read EMEM configuration\n",
+			node->name);
+		return err;
+	}
+
+	return 0;
+}
+
+static int load_timings(struct tegra_mc *mc, struct device_node *node)
+{
+	struct device_node *child;
+	struct tegra_mc_timing *timing;
+	int child_count = of_get_child_count(node);
+	int i = 0, err;
+
+	mc->timings = devm_kcalloc(mc->dev, child_count, sizeof(*timing),
+				   GFP_KERNEL);
+	if (!mc->timings)
+		return -ENOMEM;
+
+	mc->num_timings = child_count;
+
+	for_each_child_of_node(node, child) {
+		timing = &mc->timings[i++];
+
+		err = load_one_timing(mc, timing, child);
+		if (err)
+			return err;
+	}
+
+	return 0;
+}
+
+static int tegra_mc_setup_timings(struct tegra_mc *mc)
+{
+	struct device_node *node;
+	u32 ram_code, node_ram_code;
+	int err;
+
+	ram_code = tegra_read_ram_code();
+
+	mc->num_timings = 0;
+
+	for_each_child_of_node(mc->dev->of_node, node) {
+		err = of_property_read_u32(node, "nvidia,ram-code",
+					   &node_ram_code);
+		if (err || (node_ram_code != ram_code)) {
+			of_node_put(node);
+			continue;
+		}
+
+		err = load_timings(mc, node);
+		if (err)
+			return err;
+		of_node_put(node);
+		break;
+	}
+
+	if (mc->num_timings == 0)
+		dev_warn(mc->dev,
+			 "no memory timings for RAM code %u registered\n",
+			 ram_code);
+
+	return 0;
+}
+
 static const char *const status_names[32] = {
 	[ 1] = "External interrupt",
 	[ 6] = "EMEM address decode error",
@@ -251,6 +381,12 @@ static int tegra_mc_probe(struct platform_device *pdev)
 		return err;
 	}
 
+	err = tegra_mc_setup_timings(mc);
+	if (err < 0) {
+		dev_err(&pdev->dev, "failed to setup timings: %d\n", err);
+		return err;
+	}
+
 	if (IS_ENABLED(CONFIG_TEGRA_IOMMU_SMMU)) {
 		mc->smmu = tegra_smmu_probe(&pdev->dev, mc->soc->smmu, mc);
 		if (IS_ERR(mc->smmu)) {