arch/tile: introduce GXIO IORPC framework for tilegx

The GXIO I/O RPC subsystem handles exporting I/O hardware resources to
Linux and to applications running under Linux.

For instance, memory which is made available for I/O DMA must be mapped
by an I/O TLB; that means that such memory must be locked down by Linux,
so that it is not swapped or otherwise reused, as long as those I/O
TLB entries are active. Similarly, configuring direct hardware access
introduces new validation requirements. If a user application registers
memory, Linux must ensure that the supplied virtual addresses are valid,
and turn them into client physical addresses. Similarly, when Linux then
supplies those client physical addresses to the Tilera hypervisor, it
must in turn validate those before turning them into the real physical
addresses which are required by the hardware.

To the extent that these sorts of activities were required on previous
TILE architecture processors, they were implemented in a device-specific
fashion. This meant that every I/O device had its own Tilera hypervisor
driver, its own Linux driver, and in some cases its own user-level
library support. There was a large amount of more-or-less functionally
identical code in different places, particularly in the different Linux
drivers. For TILE-Gx, this support has been generalized into a common
framework, known as the I/O RPC framework or just IORPC.

The two "gxio" directories (one for headers, one for sources) start
with just a few files in each with this infrastructure commit, but
after adding support for the on-board I/O shims for networking, PCI,
USB, crypto, compression, I2CS, etc., there end up being about 20 files
in each directory.

More information on the IORPC framework is in the <hv/iorpc.h> header,
included in this commit.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>

4 files changed, 160 insertions, 0 deletions

diff --git a/arch/tile/gxio/Kconfig b/arch/tile/gxio/Kconfig
new file mode 100644
index 00000000000..8eff47fe123
--- /dev/null
+++ b/arch/tile/gxio/Kconfig
@@ -0,0 +1,5 @@
+# Support direct access to TILE-Gx hardware from user space, via the
+# gxio library, or from kernel space, via kernel IORPC support.
+config TILE_GXIO
+	bool
+	depends on TILEGX
diff --git a/arch/tile/gxio/Makefile b/arch/tile/gxio/Makefile
new file mode 100644
index 00000000000..db1ee2863d8
--- /dev/null
+++ b/arch/tile/gxio/Makefile
@@ -0,0 +1,5 @@
+#
+# Makefile for the Tile-Gx device access support.
+#
+
+obj-$(CONFIG_TILE_GXIO) += iorpc_globals.o kiorpc.o
diff --git a/arch/tile/gxio/iorpc_globals.c b/arch/tile/gxio/iorpc_globals.c
new file mode 100644
index 00000000000..e178e90805a
--- /dev/null
+++ b/arch/tile/gxio/iorpc_globals.c
@@ -0,0 +1,89 @@
+/*
+ * Copyright 2012 Tilera Corporation. 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
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ */
+
+/* This file is machine-generated; DO NOT EDIT! */
+#include "gxio/iorpc_globals.h"
+
+struct arm_pollfd_param {
+	union iorpc_pollfd pollfd;
+};
+
+int __iorpc_arm_pollfd(int fd, int pollfd_cookie)
+{
+	struct arm_pollfd_param temp;
+	struct arm_pollfd_param *params = &temp;
+
+	params->pollfd.kernel.cookie = pollfd_cookie;
+
+	return hv_dev_pwrite(fd, 0, (HV_VirtAddr) params, sizeof(*params),
+			     IORPC_OP_ARM_POLLFD);
+}
+
+EXPORT_SYMBOL(__iorpc_arm_pollfd);
+
+struct close_pollfd_param {
+	union iorpc_pollfd pollfd;
+};
+
+int __iorpc_close_pollfd(int fd, int pollfd_cookie)
+{
+	struct close_pollfd_param temp;
+	struct close_pollfd_param *params = &temp;
+
+	params->pollfd.kernel.cookie = pollfd_cookie;
+
+	return hv_dev_pwrite(fd, 0, (HV_VirtAddr) params, sizeof(*params),
+			     IORPC_OP_CLOSE_POLLFD);
+}
+
+EXPORT_SYMBOL(__iorpc_close_pollfd);
+
+struct get_mmio_base_param {
+	HV_PTE base;
+};
+
+int __iorpc_get_mmio_base(int fd, HV_PTE *base)
+{
+	int __result;
+	struct get_mmio_base_param temp;
+	struct get_mmio_base_param *params = &temp;
+
+	__result =
+	    hv_dev_pread(fd, 0, (HV_VirtAddr) params, sizeof(*params),
+			 IORPC_OP_GET_MMIO_BASE);
+	*base = params->base;
+
+	return __result;
+}
+
+EXPORT_SYMBOL(__iorpc_get_mmio_base);
+
+struct check_mmio_offset_param {
+	unsigned long offset;
+	unsigned long size;
+};
+
+int __iorpc_check_mmio_offset(int fd, unsigned long offset, unsigned long size)
+{
+	struct check_mmio_offset_param temp;
+	struct check_mmio_offset_param *params = &temp;
+
+	params->offset = offset;
+	params->size = size;
+
+	return hv_dev_pwrite(fd, 0, (HV_VirtAddr) params, sizeof(*params),
+			     IORPC_OP_CHECK_MMIO_OFFSET);
+}
+
+EXPORT_SYMBOL(__iorpc_check_mmio_offset);
diff --git a/arch/tile/gxio/kiorpc.c b/arch/tile/gxio/kiorpc.c
new file mode 100644
index 00000000000..c8096aa5a3f
--- /dev/null
+++ b/arch/tile/gxio/kiorpc.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright 2012 Tilera Corporation. 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
+ *   as published by the Free Software Foundation, version 2.
+ *
+ *   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, GOOD TITLE or
+ *   NON INFRINGEMENT.  See the GNU General Public License for
+ *   more details.
+ *
+ * TILE-Gx IORPC support for kernel I/O drivers.
+ */
+
+#include <linux/mmzone.h>
+#include <linux/module.h>
+#include <linux/io.h>
+#include <gxio/iorpc_globals.h>
+#include <gxio/kiorpc.h>
+
+#ifdef DEBUG_IORPC
+#define TRACE(FMT, ...) pr_info(SIMPLE_MSG_LINE FMT, ## __VA_ARGS__)
+#else
+#define TRACE(...)
+#endif
+
+/* Create kernel-VA-space MMIO mapping for an on-chip IO device. */
+void __iomem *iorpc_ioremap(int hv_fd, resource_size_t offset,
+			    unsigned long size)
+{
+	pgprot_t mmio_base, prot = { 0 };
+	unsigned long pfn;
+	int err;
+
+	/* Look up the shim's lotar and base PA. */
+	err = __iorpc_get_mmio_base(hv_fd, &mmio_base);
+	if (err) {
+		TRACE("get_mmio_base() failure: %d\n", err);
+		return NULL;
+	}
+
+	/* Make sure the HV driver approves of our offset and size. */
+	err = __iorpc_check_mmio_offset(hv_fd, offset, size);
+	if (err) {
+		TRACE("check_mmio_offset() failure: %d\n", err);
+		return NULL;
+	}
+
+	/*
+	 * mmio_base contains a base pfn and homing coordinates.  Turn
+	 * it into an MMIO pgprot and offset pfn.
+	 */
+	prot = hv_pte_set_lotar(prot, hv_pte_get_lotar(mmio_base));
+	pfn = pte_pfn(mmio_base) + PFN_DOWN(offset);
+
+	return ioremap_prot(PFN_PHYS(pfn), size, prot);
+}
+
+EXPORT_SYMBOL(iorpc_ioremap);