[S390] pm: xpram driver power management callbacks

Signed-off-by: Michael Holzheu <holzheu@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 126 insertions, 3 deletions

diff --git a/drivers/s390/block/xpram.c b/drivers/s390/block/xpram.c
index 0ae0c83ef879..2e9e1ecd6d82 100644
--- a/drivers/s390/block/xpram.c
+++ b/drivers/s390/block/xpram.c
@@ -39,7 +39,10 @@
 #include <linux/hdreg.h>  /* HDIO_GETGEO */
 #include <linux/sysdev.h>
 #include <linux/bio.h>
+#include <linux/suspend.h>
+#include <linux/platform_device.h>
 #include <asm/uaccess.h>
+#include <asm/checksum.h>
 
 #define XPRAM_NAME      "xpram"
 #define XPRAM_DEVS      1       /* one partition */
@@ -48,6 +51,7 @@
 typedef struct {
         unsigned int    size;           /* size of xpram segment in pages */
         unsigned int    offset;         /* start page of xpram segment */
+        unsigned int    csum;           /* partition checksum for suspend */
 } xpram_device_t;
 
 static xpram_device_t xpram_devices[XPRAM_MAX_DEVS];
@@ -138,7 +142,7 @@ static long xpram_page_out (unsigned long page_addr, unsigned int xpage_index)
 /*
  * Check if xpram is available.
  */
-static int __init xpram_present(void)
+static int xpram_present(void)
 {
         unsigned long mem_page;
         int rc;
@@ -154,7 +158,7 @@ static int __init xpram_present(void)
 /*
  * Return index of the last available xpram page.
  */
-static unsigned long __init xpram_highest_page_index(void)
+static unsigned long xpram_highest_page_index(void)
 {
         unsigned int page_index, add_bit;
         unsigned long mem_page;
@@ -383,6 +387,106 @@ out:
 }
 
 /*
+ * Save checksums for all partitions.
+ */
+static int xpram_save_checksums(void)
+{
+        unsigned long mem_page;
+        int rc, i;
+
+        rc = 0;
+        mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
+        if (!mem_page)
+                return -ENOMEM;
+        for (i = 0; i < xpram_devs; i++) {
+                rc = xpram_page_in(mem_page, xpram_devices[i].offset);
+                if (rc)
+                        goto fail;
+                xpram_devices[i].csum = csum_partial((const void *) mem_page,
+                                                     PAGE_SIZE, 0);
+        }
+fail:
+        free_page(mem_page);
+        return rc ? -ENXIO : 0;
+}
+
+/*
+ * Verify checksums for all partitions.
+ */
+static int xpram_validate_checksums(void)
+{
+        unsigned long mem_page;
+        unsigned int csum;
+        int rc, i;
+
+        rc = 0;
+        mem_page = (unsigned long) __get_free_page(GFP_KERNEL);
+        if (!mem_page)
+                return -ENOMEM;
+        for (i = 0; i < xpram_devs; i++) {
+                rc = xpram_page_in(mem_page, xpram_devices[i].offset);
+                if (rc)
+                        goto fail;
+                csum = csum_partial((const void *) mem_page, PAGE_SIZE, 0);
+                if (xpram_devices[i].csum != csum) {
+                        rc = -EINVAL;
+                        goto fail;
+                }
+        }
+fail:
+        free_page(mem_page);
+        return rc ? -ENXIO : 0;
+}
+
+/*
+ * Resume failed: Print error message and call panic.
+ */
+static void xpram_resume_error(const char *message)
+{
+        pr_err("Resume error: %s\n", message);
+        panic("xpram resume error\n");
+}
+
+/*
+ * Check if xpram setup changed between suspend and resume.
+ */
+static int xpram_restore(struct device *dev)
+{
+        if (!xpram_pages)
+                return 0;
+        if (xpram_present() != 0)
+                xpram_resume_error("xpram disappeared");
+        if (xpram_pages != xpram_highest_page_index() + 1)
+                xpram_resume_error("Size of xpram changed");
+        if (xpram_validate_checksums())
+                xpram_resume_error("Data of xpram changed");
+        return 0;
+}
+
+/*
+ * Save necessary state in suspend.
+ */
+static int xpram_freeze(struct device *dev)
+{
+        return xpram_save_checksums();
+}
+
+static struct dev_pm_ops xpram_pm_ops = {
+        .freeze         = xpram_freeze,
+        .restore        = xpram_restore,
+};
+
+static struct platform_driver xpram_pdrv = {
+        .driver = {
+                .name   = XPRAM_NAME,
+                .owner  = THIS_MODULE,
+                .pm     = &xpram_pm_ops,
+        },
+};
+
+static struct platform_device *xpram_pdev;
+
+/*
  * Finally, the init/exit functions.
  */
 static void __exit xpram_exit(void)
@@ -394,6 +498,8 @@ static void __exit xpram_exit(void)
                 put_disk(xpram_disks[i]);
         }
         unregister_blkdev(XPRAM_MAJOR, XPRAM_NAME);
+        platform_device_unregister(xpram_pdev);
+        platform_driver_unregister(&xpram_pdrv);
 }
 
 static int __init xpram_init(void)
@@ -411,7 +517,24 @@ static int __init xpram_init(void)
         rc = xpram_setup_sizes(xpram_pages);
         if (rc)
                 return rc;
-        return xpram_setup_blkdev();
+        rc = platform_driver_register(&xpram_pdrv);
+        if (rc)
+                return rc;
+        xpram_pdev = platform_device_register_simple(XPRAM_NAME, -1, NULL, 0);
+        if (IS_ERR(xpram_pdev)) {
+                rc = PTR_ERR(xpram_pdev);
+                goto fail_platform_driver_unregister;
+        }
+        rc = xpram_setup_blkdev();
+        if (rc)
+                goto fail_platform_device_unregister;
+        return 0;
+
+fail_platform_device_unregister:
+        platform_device_unregister(xpram_pdev);
+fail_platform_driver_unregister:
+        platform_driver_unregister(&xpram_pdrv);
+        return rc;
 }
 
 module_init(xpram_init);