Implement vas_init() and vas_exit() functions for a new VAS module.
This VAS module is essentially a library for other device drivers
and kernel users of the NX coprocessors like NX-842 and NX-GZIP.
In the future this will be extended to add support for user space
to access the NX coprocessors.

VAS is currently only supported with 64K page size.

Signed-off-by: Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>
---
Changelog[v5]:
        - [Ben Herrenschmidt]: Create and use platform device tree nodes,
          fix up the "reg" properties for the VAS DT node and use the
          platform device helpers to parse the reg properties; Use linked
          list of VAS instances (don't assume vasids are sequential);
          Use CONFIG_PPC_VAS instead of CONFIG_VAS.

Changelog[v4]:
        - [Michael Neuling] Fix some accidental deletions; fix help text
          in Kconfig; change vas_initialized to a function; move from
          drivers/misc to arch/powerpc/kernel
        - Drop the vas_window_reset() interface. It is not needed as
          window will be initialized before each use.
        - Add a "depends on PPC_64K_PAGES"

Changelog[v3]:
        - Zero vas_instances memory on allocation
        - [Haren Myneni] Fix description in Kconfig
Changelog[v2]:
        - Get HVWC, UWC and window address parameters from device tree.
---
 .../devicetree/bindings/powerpc/ibm,vas.txt        |  24 +++
 MAINTAINERS                                        |  18 ++
 arch/powerpc/platforms/powernv/Kconfig             |  14 ++
 arch/powerpc/platforms/powernv/Makefile            |   1 +
 arch/powerpc/platforms/powernv/vas-window.c        |  19 +++
 arch/powerpc/platforms/powernv/vas.c               | 183 +++++++++++++++++++++
 arch/powerpc/platforms/powernv/vas.h               |  10 +-
 7 files changed, 267 insertions(+), 2 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/powerpc/ibm,vas.txt
 create mode 100644 arch/powerpc/platforms/powernv/vas-window.c
 create mode 100644 arch/powerpc/platforms/powernv/vas.c

diff --git a/Documentation/devicetree/bindings/powerpc/ibm,vas.txt 
b/Documentation/devicetree/bindings/powerpc/ibm,vas.txt
new file mode 100644
index 0000000..8468a3a
--- /dev/null
+++ b/Documentation/devicetree/bindings/powerpc/ibm,vas.txt
@@ -0,0 +1,24 @@
+* IBM Powerpc Virtual Accelerator Switchboard (VAS)
+
+VAS is a hardware mechanism that allows ekrnel subsystems and user processes
+to directly submit compression and other requests to Nest accelerators (NX)
+or other coprocessors functions.
+
+Required properties:
+- compatible : should be "ibm,vas" or "ibm,power9-vas"
+- ibm,vas-id : A unique identifier for each instance of VAS in the system
+- reg : Should contain 4 pairs of 64-bit fields specifying the Hypervisor
+  window context start and length, OS/User window context start and length,
+  "Paste address" start and length, "Paste window id" start bit and number
+  of bits)
+- name : "vas"
+
+Example:
+
+       vas@6019100000000 {
+               compatible = "ibm,vas", "ibm,power9-vas";
+               reg = <0x6019100000000 0x2000000 0x6019000000000 0x100000000 
0x8000000000000 0x100000000 0x20 0x10>;
+               name = "vas";
+               ibm,vas-id = <0x1>;
+       };
+
diff --git a/MAINTAINERS b/MAINTAINERS
index 3c41902..edc58c9 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -6425,6 +6425,24 @@ F:       drivers/crypto/nx/nx.*
 F:     drivers/crypto/nx/nx_csbcpb.h
 F:     drivers/crypto/nx/nx_debugfs.h
 
+IBM Power Virtual Accelerator Switchboard
+M:     Sukadev Bhattiprolu
+L:     linuxppc-dev@lists.ozlabs.org
+S:     Supported
+F:     arch/powerpc/platforms/powernv/vas*
+F:     arch/powerpc/include/asm/vas.h
+F:     arch/powerpc/include/uapi/asm/vas.h
+
+IBM Power 842 compression accelerator
+M:     Haren Myneni <ha...@us.ibm.com>
+S:     Supported
+F:     drivers/crypto/nx/Makefile
+F:     drivers/crypto/nx/Kconfig
+F:     drivers/crypto/nx/nx-842*
+F:     include/linux/sw842.h
+F:     crypto/842.c
+F:     lib/842/
+
 IBM Power Linux RAID adapter
 M:     Brian King <brk...@us.ibm.com>
 S:     Supported
diff --git a/arch/powerpc/platforms/powernv/Kconfig 
b/arch/powerpc/platforms/powernv/Kconfig
index 6a6f4ef..f565454 100644
--- a/arch/powerpc/platforms/powernv/Kconfig
+++ b/arch/powerpc/platforms/powernv/Kconfig
@@ -30,3 +30,17 @@ config OPAL_PRD
        help
          This enables the opal-prd driver, a facility to run processor
          recovery diagnostics on OpenPower machines
+
+config PPC_VAS
+       bool "IBM Virtual Accelerator Switchboard (VAS)"
+       depends on PPC_POWERNV && PPC_64K_PAGES
+       default n
+       help
+         This enables support for IBM Virtual Accelerator Switchboard (VAS).
+
+         VAS allows accelerators in co-processors like NX-GZIP and NX-842
+         to be accessible to kernel subsystems and user processes.
+
+         VAS adapters are found in POWER9 based systems.
+
+         If unsure, say N.
diff --git a/arch/powerpc/platforms/powernv/Makefile 
b/arch/powerpc/platforms/powernv/Makefile
index b5d98cb..e4db292 100644
--- a/arch/powerpc/platforms/powernv/Makefile
+++ b/arch/powerpc/platforms/powernv/Makefile
@@ -12,3 +12,4 @@ obj-$(CONFIG_PPC_SCOM)        += opal-xscom.o
 obj-$(CONFIG_MEMORY_FAILURE)   += opal-memory-errors.o
 obj-$(CONFIG_TRACEPOINTS)      += opal-tracepoints.o
 obj-$(CONFIG_OPAL_PRD) += opal-prd.o
+obj-$(CONFIG_PPC_VAS)  += vas.o vas-window.o
diff --git a/arch/powerpc/platforms/powernv/vas-window.c 
b/arch/powerpc/platforms/powernv/vas-window.c
new file mode 100644
index 0000000..6156fbe
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/vas-window.c
@@ -0,0 +1,19 @@
+/*
+ * Copyright 2016 IBM Corp.
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/types.h>
+#include <linux/mutex.h>
+
+#include "vas.h"
+
+/* stub for now */
+int vas_win_close(struct vas_window *window)
+{
+       return -1;
+}
diff --git a/arch/powerpc/platforms/powernv/vas.c 
b/arch/powerpc/platforms/powernv/vas.c
new file mode 100644
index 0000000..556156b
--- /dev/null
+++ b/arch/powerpc/platforms/powernv/vas.c
@@ -0,0 +1,183 @@
+/*
+ * Copyright 2016 IBM Corp.
+ *
+ * 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; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/export.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+#include <linux/of.h>
+
+#include "vas.h"
+
+static bool init_done;
+LIST_HEAD(vas_instances);
+
+static int init_vas_instance(struct platform_device *pdev)
+{
+       int rc, vasid;
+       struct vas_instance *vinst;
+       struct device_node *dn = pdev->dev.of_node;
+       struct resource *res;
+
+       rc = of_property_read_u32(dn, "ibm,vas-id", &vasid);
+       if (rc) {
+               pr_err("VAS: No ibm,vas-id property for %s?\n", pdev->name);
+               return -ENODEV;
+       }
+
+       if (pdev->num_resources != 4) {
+               pr_err("VAS: Unexpected DT configuration for [%s, %d]\n",
+                               pdev->name, vasid);
+               return -ENODEV;
+       }
+
+       vinst = kcalloc(1, sizeof(*vinst), GFP_KERNEL);
+       if (!vinst)
+               return -ENOMEM;
+
+       INIT_LIST_HEAD(&vinst->node);
+       ida_init(&vinst->ida);
+       mutex_init(&vinst->mutex);
+       vinst->vas_id = vasid;
+       vinst->pdev = pdev;
+
+       res = &pdev->resource[0];
+       vinst->hvwc_bar_start = res->start;
+       vinst->hvwc_bar_len = res->end - res->start + 1;
+
+       res = &pdev->resource[1];
+       vinst->uwc_bar_start = res->start;
+       vinst->uwc_bar_len = res->end - res->start + 1;
+
+       res = &pdev->resource[2];
+       vinst->paste_base_addr = res->start;
+
+       res = &pdev->resource[3];
+       vinst->paste_win_id_shift = 63 - res->end;
+
+       pr_devel("VAS: Initialized instance [%s, %d], paste_base 0x%llx, "
+                       "paste_win_id_shift 0x%llx\n", pdev->name, vasid,
+                       vinst->paste_base_addr, vinst->paste_win_id_shift);
+
+       vinst->ready = true;
+       list_add(&vinst->node, &vas_instances);
+
+       dev_set_drvdata(&pdev->dev, vinst);
+
+       return 0;
+}
+
+/*
+ * Although this is read/used multiple times, it is written to only
+ * during initialization.
+ */
+struct vas_instance *find_vas_instance(int vasid)
+{
+       struct list_head *ent;
+       struct vas_instance *vinst;
+
+       list_for_each(ent, &vas_instances) {
+               vinst = list_entry(ent, struct vas_instance, node);
+               if (vinst->vas_id == vasid)
+                       return vinst;
+       }
+
+       pr_devel("VAS: Instance %d not found\n", vasid);
+       return NULL;
+}
+
+bool vas_initialized(void)
+{
+       return init_done;
+}
+
+static int vas_probe(struct platform_device *pdev)
+{
+       if (!pdev || !pdev->dev.of_node)
+               return -ENODEV;
+
+       return init_vas_instance(pdev);
+}
+
+static void free_inst(struct vas_instance *vinst)
+{
+       list_del(&vinst->node);
+
+       kfree(vinst);
+}
+
+static int vas_remove(struct platform_device *pdev)
+{
+       struct vas_instance *vinst;
+
+       vinst = dev_get_drvdata(&pdev->dev);
+
+       pr_devel("VAS: Removed instance [%s, %d]\n", pdev->name,
+                               vinst->vas_id);
+       free_inst(vinst);
+
+       return 0;
+}
+static const struct of_device_id powernv_vas_match[] = {
+       { .compatible = "ibm,vas",},
+       {},
+};
+
+static struct platform_driver vas_driver = {
+       .driver = {
+               .name = "vas",
+               .of_match_table = powernv_vas_match,
+       },
+       .probe = vas_probe,
+       .remove = vas_remove,
+};
+
+module_platform_driver(vas_driver);
+
+int vas_init(void)
+{
+       int found = 0;
+       struct device_node *dn;
+
+       for_each_compatible_node(dn, NULL, "ibm,vas") {
+               of_platform_device_create(dn, NULL, NULL);
+               found++;
+       }
+
+       if (!found)
+               return -ENODEV;
+
+       pr_devel("VAS: Found %d instances\n", found);
+       init_done = true;
+
+       return 0;
+}
+
+void vas_exit(void)
+{
+       struct list_head *ent;
+       struct vas_instance *vinst;
+
+       list_for_each(ent, &vas_instances) {
+               vinst = list_entry(ent, struct vas_instance, node);
+               of_platform_depopulate(&vinst->pdev->dev);
+       }
+
+       init_done = false;
+}
+
+module_init(vas_init);
+module_exit(vas_exit);
+MODULE_DESCRIPTION("Bare metal IBM Virtual Accelerator Switchboard");
+MODULE_AUTHOR("Sukadev Bhattiprolu <suka...@linux.vnet.ibm.com>");
+MODULE_LICENSE("GPL");
diff --git a/arch/powerpc/platforms/powernv/vas.h 
b/arch/powerpc/platforms/powernv/vas.h
index 312a378..150d7b1 100644
--- a/arch/powerpc/platforms/powernv/vas.h
+++ b/arch/powerpc/platforms/powernv/vas.h
@@ -291,14 +291,17 @@ enum vas_notify_after_count {
  */
 struct vas_instance {
        int vas_id;
+       bool ready;
        struct ida ida;
+       struct list_head node;
+       struct platform_device *pdev;
 
        u64 hvwc_bar_start;
        u64 hvwc_bar_len;
        u64 uwc_bar_start;
        u64 uwc_bar_len;
-       u64 win_base_addr;
-       u64 win_id_shift;
+       u64 paste_base_addr;
+       u64 paste_win_id_shift;
 
        struct mutex mutex;
        struct vas_window *rxwin[VAS_COP_TYPE_MAX];
@@ -379,4 +382,7 @@ struct vas_winctx {
        enum vas_notify_after_count notify_after_count;
 };
 
+extern bool vas_initialized(void);
+extern struct vas_instance *find_vas_instance(int vasid);
+
 #endif /* _VAS_H */
-- 
2.7.4

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