[POWERPC] Generic DCR infrastructure

This patch adds new dcr_map/dcr_read/dcr_write accessors for DCRs that
can be used by drivers to transparently address either native DCRs or
memory mapped DCRs. The implementation for memory mapped DCRs is done
after the binding being currently worked on for SLOF and the Axon
chipset. This patch enables it for the cell native platform

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 137 insertions, 0 deletions

diff --git a/arch/powerpc/sysdev/dcr.c b/arch/powerpc/sysdev/dcr.c
new file mode 100644
index 000000000000..dffeeaeca1d9
--- /dev/null
+++ b/arch/powerpc/sysdev/dcr.c
@@ -0,0 +1,137 @@
+/*
+ * (c) Copyright 2006 Benjamin Herrenschmidt, IBM Corp.
+ *                    <benh@kernel.crashing.org>
+ *
+ *   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.
+ *
+ *   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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#undef DEBUG
+
+#include <linux/kernel.h>
+#include <asm/prom.h>
+#include <asm/dcr.h>
+
+unsigned int dcr_resource_start(struct device_node *np, unsigned int index)
+{
+        unsigned int ds;
+        const u32 *dr = get_property(np, "dcr-reg", &ds);
+
+        if (dr == NULL || ds & 1 || index >= (ds / 8))
+                return 0;
+
+        return dr[index * 2];
+}
+
+unsigned int dcr_resource_len(struct device_node *np, unsigned int index)
+{
+        unsigned int ds;
+        const u32 *dr = get_property(np, "dcr-reg", &ds);
+
+        if (dr == NULL || ds & 1 || index >= (ds / 8))
+                return 0;
+
+        return dr[index * 2 + 1];
+}
+
+#ifndef CONFIG_PPC_DCR_NATIVE
+
+static struct device_node * find_dcr_parent(struct device_node * node)
+{
+        struct device_node *par, *tmp;
+        const u32 *p;
+
+        for (par = of_node_get(node); par;) {
+                if (get_property(par, "dcr-controller", NULL))
+                        break;
+                p = get_property(par, "dcr-parent", NULL);
+                tmp = par;
+                if (p == NULL)
+                        par = of_get_parent(par);
+                else
+                        par = of_find_node_by_phandle(*p);
+                of_node_put(tmp);
+        }
+        return par;
+}
+
+u64 of_translate_dcr_address(struct device_node *dev,
+                             unsigned int dcr_n,
+                             unsigned int *out_stride)
+{
+        struct device_node *dp;
+        const u32 *p;
+        unsigned int stride;
+        u64 ret;
+
+        dp = find_dcr_parent(dev);
+        if (dp == NULL)
+                return OF_BAD_ADDR;
+
+        /* Stride is not properly defined yet, default to 0x10 for Axon */
+        p = get_property(dp, "dcr-mmio-stride", NULL);
+        stride = (p == NULL) ? 0x10 : *p;
+
+        /* XXX FIXME: Which property name is to use of the 2 following ? */
+        p = get_property(dp, "dcr-mmio-range", NULL);
+        if (p == NULL)
+                p = get_property(dp, "dcr-mmio-space", NULL);
+        if (p == NULL)
+                return OF_BAD_ADDR;
+
+        /* Maybe could do some better range checking here */
+        ret = of_translate_address(dp, p);
+        if (ret != OF_BAD_ADDR)
+                ret += (u64)(stride) * (u64)dcr_n;
+        if (out_stride)
+                *out_stride = stride;
+        return ret;
+}
+
+dcr_host_t dcr_map(struct device_node *dev, unsigned int dcr_n,
+                   unsigned int dcr_c)
+{
+        dcr_host_t ret = { .token = NULL, .stride = 0 };
+        u64 addr;
+
+        pr_debug("dcr_map(%s, 0x%x, 0x%x)\n",
+                 dev->full_name, dcr_n, dcr_c);
+
+        addr = of_translate_dcr_address(dev, dcr_n, &ret.stride);
+        pr_debug("translates to addr: 0x%lx, stride: 0x%x\n",
+                 addr, ret.stride);
+        if (addr == OF_BAD_ADDR)
+                return ret;
+        pr_debug("mapping 0x%x bytes\n", dcr_c * ret.stride);
+        ret.token = ioremap(addr, dcr_c * ret.stride);
+        if (ret.token == NULL)
+                return ret;
+        pr_debug("mapped at 0x%p -> base is 0x%p\n",
+                 ret.token, ret.token - dcr_n * ret.stride);
+        ret.token -= dcr_n * ret.stride;
+        return ret;
+}
+
+void dcr_unmap(dcr_host_t host, unsigned int dcr_n, unsigned int dcr_c)
+{
+        dcr_host_t h = host;
+
+        if (h.token == NULL)
+                return;
+        h.token -= dcr_n * h.stride;
+        iounmap(h.token);
+        h.token = NULL;
+}
+
+#endif /* !defined(CONFIG_PPC_DCR_NATIVE) */