[POWERPC] cell: enable RTAS-based PTCAL for Cell XDR memory

Enable Periodic Recalibration (PTCAL) support for Cell XDR memory,
using the new ibm,cbe-start-ptcal and ibm,cbe-stop-ptcal RTAS calls.

Tested on QS20 and QS21 (by Thomas Huth). It seems that SLOF has
problems disabling, at least on QS20; this patch should only be
used once these problems have been addressed.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com>

1 files changed, 160 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/cell/ras.c b/arch/powerpc/platforms/cell/ras.c
index 0984c7071695..b5ebc916388b 100644
--- a/arch/powerpc/platforms/cell/ras.c
+++ b/arch/powerpc/platforms/cell/ras.c
@@ -3,11 +3,13 @@
 #include <linux/types.h>
 #include <linux/kernel.h>
 #include <linux/smp.h>
+#include <linux/reboot.h>
 
 #include <asm/reg.h>
 #include <asm/io.h>
 #include <asm/prom.h>
 #include <asm/machdep.h>
+#include <asm/rtas.h>
 
 #include "ras.h"
 #include "cbe_regs.h"
@@ -82,6 +84,164 @@ static int cbe_machine_check_handler(struct pt_regs *regs)
         return 0;
 }
 
+struct ptcal_area {
+        struct list_head list;
+        int nid;
+        int order;
+        struct page *pages;
+};
+
+static LIST_HEAD(ptcal_list);
+
+static int ptcal_start_tok, ptcal_stop_tok;
+
+static int __init cbe_ptcal_enable_on_node(int nid, int order)
+{
+        struct ptcal_area *area;
+        int ret = -ENOMEM;
+        unsigned long addr;
+
+#ifdef CONFIG_CRASH_DUMP
+        rtas_call(ptcal_stop_tok, 1, 1, NULL, nid);
+#endif
+
+        area = kmalloc(sizeof(*area), GFP_KERNEL);
+        if (!area)
+                goto out_err;
+
+        area->nid = nid;
+        area->order = order;
+        area->pages = alloc_pages_node(area->nid, GFP_KERNEL, area->order);
+
+        if (!area->pages)
+                goto out_free_area;
+
+        addr = __pa(page_address(area->pages));
+
+        ret = -EIO;
+        if (rtas_call(ptcal_start_tok, 3, 1, NULL, area->nid,
+                                (unsigned int)(addr >> 32),
+                                (unsigned int)(addr & 0xffffffff))) {
+                printk(KERN_ERR "%s: error enabling PTCAL on node %d!\n",
+                                __FUNCTION__, nid);
+                goto out_free_pages;
+        }
+
+        list_add(&area->list, &ptcal_list);
+
+        return 0;
+
+out_free_pages:
+        __free_pages(area->pages, area->order);
+out_free_area:
+        kfree(area);
+out_err:
+        return ret;
+}
+
+static int __init cbe_ptcal_enable(void)
+{
+        const u32 *size;
+        struct device_node *np;
+        int order, found_mic = 0;
+
+        np = of_find_node_by_path("/rtas");
+        if (!np)
+                return -ENODEV;
+
+        size = get_property(np, "ibm,cbe-ptcal-size", NULL);
+        if (!size)
+                return -ENODEV;
+
+        pr_debug("%s: enabling PTCAL, size = 0x%x\n", __FUNCTION__, *size);
+        order = get_order(*size);
+        of_node_put(np);
+
+        /* support for malta device trees, with be@/mic@ nodes */
+        for_each_node_by_type(np, "mic-tm") {
+                cbe_ptcal_enable_on_node(of_node_to_nid(np), order);
+                found_mic = 1;
+        }
+
+        if (found_mic)
+                return 0;
+
+        /* support for older device tree - use cpu nodes */
+        for_each_node_by_type(np, "cpu") {
+                const u32 *nid = get_property(np, "node-id", NULL);
+                if (!nid) {
+                        printk(KERN_ERR "%s: node %s is missing node-id?\n",
+                                        __FUNCTION__, np->full_name);
+                        continue;
+                }
+                cbe_ptcal_enable_on_node(*nid, order);
+                found_mic = 1;
+        }
+
+        return found_mic ? 0 : -ENODEV;
+}
+
+static int cbe_ptcal_disable(void)
+{
+        struct ptcal_area *area, *tmp;
+        int ret = 0;
+
+        pr_debug("%s: disabling PTCAL\n", __FUNCTION__);
+
+        list_for_each_entry_safe(area, tmp, &ptcal_list, list) {
+                /* disable ptcal on this node */
+                if (rtas_call(ptcal_stop_tok, 1, 1, NULL, area->nid)) {
+                        printk(KERN_ERR "%s: error disabling PTCAL "
+                                        "on node %d!\n", __FUNCTION__,
+                                        area->nid);
+                        ret = -EIO;
+                        continue;
+                }
+
+                /* ensure we can access the PTCAL area */
+                memset(page_address(area->pages), 0,
+                                1 << (area->order + PAGE_SHIFT));
+
+                /* clean up */
+                list_del(&area->list);
+                __free_pages(area->pages, area->order);
+                kfree(area);
+        }
+
+        return ret;
+}
+
+static int cbe_ptcal_notify_reboot(struct notifier_block *nb,
+                unsigned long code, void *data)
+{
+        return cbe_ptcal_disable();
+}
+
+static struct notifier_block cbe_ptcal_reboot_notifier = {
+        .notifier_call = cbe_ptcal_notify_reboot
+};
+
+int __init cbe_ptcal_init(void)
+{
+        int ret;
+        ptcal_start_tok = rtas_token("ibm,cbe-start-ptcal");
+        ptcal_stop_tok = rtas_token("ibm,cbe-stop-ptcal");
+
+        if (ptcal_start_tok == RTAS_UNKNOWN_SERVICE
+                        || ptcal_stop_tok == RTAS_UNKNOWN_SERVICE)
+                return -ENODEV;
+
+        ret = register_reboot_notifier(&cbe_ptcal_reboot_notifier);
+        if (ret) {
+                printk(KERN_ERR "Can't disable PTCAL, so not enabling\n");
+                return ret;
+        }
+
+        return cbe_ptcal_enable();
+}
+
+arch_initcall(cbe_ptcal_init);
+
 void __init cbe_ras_init(void)
 {
         unsigned long hid0;