msm: Add MSM IOMMU support

Add support for the IOMMUs found on the upcoming Qualcomm
MSM8x60 chips. These IOMMUs allow virtualization of the
address space used by most of the multimedia cores on these
chips.
Signed-off-by: Stepan Moskovchenko <stepanm@codeaurora.org>
Signed-off-by: Daniel Walker <dwalker@codeaurora.org>

arch/arm/mach-msm/include/mach/iommu.h

+/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 and
+ * only version 2 as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#ifndef MSM_IOMMU_H
+#define MSM_IOMMU_H
+
+#include <linux/interrupt.h>
+
+/* Maximum number of Machine IDs that we are allowing to be mapped to the same
+ * context bank. The number of MIDs mapped to the same CB does not affect
+ * performance, but there is a practical limit on how many distinct MIDs may
+ * be present. These mappings are typically determined at design time and are
+ * not expected to change at run time.
+ */
+#define MAX_NUM_MIDS	16
+
+/**
+ * struct msm_iommu_dev - a single IOMMU hardware instance
+ * name		Human-readable name given to this IOMMU HW instance
+ * clk_rate	Rate to set for this IOMMU's clock, if applicable to this
+ *		particular IOMMU. 0 means don't set a rate.
+ *		-1 means it is an AXI clock with no valid rate
+ *
+ */
+struct msm_iommu_dev {
+	const char *name;
+	int clk_rate;
+};
+
+/**
+ * struct msm_iommu_ctx_dev - an IOMMU context bank instance
+ * name		Human-readable name given to this context bank
+ * num		Index of this context bank within the hardware
+ * mids		List of Machine IDs that are to be mapped into this context
+ *		bank, terminated by -1. The MID is a set of signals on the
+ *		AXI bus that identifies the function associated with a specific
+ *		memory request. (See ARM spec).
+ */
+struct msm_iommu_ctx_dev {
+	const char *name;
+	int num;
+	int mids[MAX_NUM_MIDS];
+};
+
+
+/**
+ * struct msm_iommu_drvdata - A single IOMMU hardware instance
+ * @base:	IOMMU config port base address (VA)
+ * @irq:	Interrupt number
+  *
+ * A msm_iommu_drvdata holds the global driver data about a single piece
+ * of an IOMMU hardware instance.
+ */
+struct msm_iommu_drvdata {
+	void __iomem *base;
+	int irq;
+};
+
+/**
+ * struct msm_iommu_ctx_drvdata - an IOMMU context bank instance
+ * @num:		Hardware context number of this context
+ * @pdev:		Platform device associated wit this HW instance
+ * @attached_elm:	List element for domains to track which devices are
+ *			attached to them
+ *
+ * A msm_iommu_ctx_drvdata holds the driver data for a single context bank
+ * within each IOMMU hardware instance
+ */
+struct msm_iommu_ctx_drvdata {
+	int num;
+	struct platform_device *pdev;
+	struct list_head attached_elm;
+};
+
+/*
+ * Look up an IOMMU context device by its context name. NULL if none found.
+ * Useful for testing and drivers that do not yet fully have IOMMU stuff in
+ * their platform devices.
+ */
+struct device *msm_iommu_get_ctx(const char *ctx_name);
+
+/*
+ * Interrupt handler for the IOMMU context fault interrupt. Hooking the
+ * interrupt is not supported in the API yet, but this will print an error
+ * message and dump useful IOMMU registers.
+ */
+irqreturn_t msm_iommu_fault_handler(int irq, void *dev_id);
+
+#endif