iommu/omap: Add support for configuring dsp iommus on DRA7xx

The DSP MMUs on DRA7xx SoC requires configuring an additional
MMU_CONFIG register present in the DSP_SYSTEM sub module. This
setting dictates whether the DSP Core's MDMA and EDMA traffic
is routed through the respective MMU or not. Add the support
to the OMAP iommu driver so that the traffic is not bypassed
when enabling the MMUs.

The MMU_CONFIG register has two different bits for enabling
each of these two MMUs present in the DSP processor sub-system
on DRA7xx. An id field is added to the OMAP iommu object to
identify and enable each IOMMU. The id information and the
DSP_SYSTEM.MMU_CONFIG register programming is achieved through
the processing of the optional "ti,syscon-mmuconfig" property.
A proper value is assigned to the id field only when this
property is present.

Signed-off-by: Suman Anna <s-anna@ti.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/omap-iommu.c

@@ -26,6 +26,8 @@
 #include <linux/of_iommu.h>
 #include <linux/of_irq.h>
 #include <linux/of_platform.h>
+#include <linux/regmap.h>
+#include <linux/mfd/syscon.h>
 
 #include <asm/cacheflush.h>
 
@@ -112,6 +114,18 @@ void omap_iommu_restore_ctx(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(omap_iommu_restore_ctx);
 
+static void dra7_cfg_dspsys_mmu(struct omap_iommu *obj, bool enable)
+{
+	u32 val, mask;
+
+	if (!obj->syscfg)
+		return;
+
+	mask = (1 << (obj->id * DSP_SYS_MMU_CONFIG_EN_SHIFT));
+	val = enable ? mask : 0;
+	regmap_update_bits(obj->syscfg, DSP_SYS_MMU_CONFIG, mask, val);
+}
+
 static void __iommu_set_twl(struct omap_iommu *obj, bool on)
 {
 	u32 l = iommu_read_reg(obj, MMU_CNTL);
@@ -147,6 +161,8 @@ static int omap2_iommu_enable(struct omap_iommu *obj)
 
 	iommu_write_reg(obj, pa, MMU_TTB);
 
+	dra7_cfg_dspsys_mmu(obj, true);
+
 	if (obj->has_bus_err_back)
 		iommu_write_reg(obj, MMU_GP_REG_BUS_ERR_BACK_EN, MMU_GP_REG);
 
@@ -161,6 +177,7 @@ static void omap2_iommu_disable(struct omap_iommu *obj)
 
 	l &= ~MMU_CNTL_MASK;
 	iommu_write_reg(obj, l, MMU_CNTL);
+	dra7_cfg_dspsys_mmu(obj, false);
 
 	dev_dbg(obj->dev, "%s is shutting down\n", obj->name);
 }
@@ -864,6 +881,42 @@ static void omap_iommu_detach(struct omap_iommu *obj)
 	dev_dbg(obj->dev, "%s: %s\n", __func__, obj->name);
 }
 
+static int omap_iommu_dra7_get_dsp_system_cfg(struct platform_device *pdev,
+					      struct omap_iommu *obj)
+{
+	struct device_node *np = pdev->dev.of_node;
+	int ret;
+
+	if (!of_device_is_compatible(np, "ti,dra7-dsp-iommu"))
+		return 0;
+
+	if (!of_property_read_bool(np, "ti,syscon-mmuconfig")) {
+		dev_err(&pdev->dev, "ti,syscon-mmuconfig property is missing\n");
+		return -EINVAL;
+	}
+
+	obj->syscfg =
+		syscon_regmap_lookup_by_phandle(np, "ti,syscon-mmuconfig");
+	if (IS_ERR(obj->syscfg)) {
+		/* can fail with -EPROBE_DEFER */
+		ret = PTR_ERR(obj->syscfg);
+		return ret;
+	}
+
+	if (of_property_read_u32_index(np, "ti,syscon-mmuconfig", 1,
+				       &obj->id)) {
+		dev_err(&pdev->dev, "couldn't get the IOMMU instance id within subsystem\n");
+		return -EINVAL;
+	}
+
+	if (obj->id != 0 && obj->id != 1) {
+		dev_err(&pdev->dev, "invalid IOMMU instance id\n");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 /*
  *	OMAP Device MMU(IOMMU) detection
  */
@@ -907,6 +960,10 @@ static int omap_iommu_probe(struct platform_device *pdev)
 	if (IS_ERR(obj->regbase))
 		return PTR_ERR(obj->regbase);
 
+	err = omap_iommu_dra7_get_dsp_system_cfg(pdev, obj);
+	if (err)
+		return err;
+
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0)
 		return -ENODEV;
@@ -943,6 +1000,7 @@ static const struct of_device_id omap_iommu_of_match[] = {
 	{ .compatible = "ti,omap2-iommu" },
 	{ .compatible = "ti,omap4-iommu" },
 	{ .compatible = "ti,dra7-iommu"	},
+	{ .compatible = "ti,dra7-dsp-iommu" },
 	{},
 };
 

drivers/iommu/omap-iommu.h

@@ -30,6 +30,7 @@ struct iotlb_entry {
 struct omap_iommu {
 	const char	*name;
 	void __iomem	*regbase;
+	struct regmap	*syscfg;
 	struct device	*dev;
 	struct iommu_domain *domain;
 	struct dentry	*debug_dir;
@@ -48,6 +49,7 @@ struct omap_iommu {
 	void *ctx; /* iommu context: registres saved area */
 
 	int has_bus_err_back;
+	u32 id;
 };
 
 struct cr_regs {
@@ -158,6 +160,13 @@ static inline struct omap_iommu *dev_to_omap_iommu(struct device *dev)
 	 ((pgsz) == MMU_CAM_PGSZ_64K) ? 0xffff0000 :	\
 	 ((pgsz) == MMU_CAM_PGSZ_4K)  ? 0xfffff000 : 0)
 
+/*
+ * DSP_SYSTEM registers and bit definitions (applicable only for DRA7xx DSP)
+ */
+#define DSP_SYS_REVISION		0x00
+#define DSP_SYS_MMU_CONFIG		0x18
+#define DSP_SYS_MMU_CONFIG_EN_SHIFT	4
+
 /*
  * utilities for super page(16MB, 1MB, 64KB and 4KB)
  */