drivers/vfio/platform/reset/vfio_platform_bcmflexrm.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Copyright (C) 2017 Broadcom
   4  */
   5
   6 /*
   7  * This driver provides reset support for Broadcom FlexRM ring manager
   8  * to VFIO platform.
   9  */
  10
  11 #include <linux/delay.h>
  12 #include <linux/device.h>
  13 #include <linux/init.h>
  14 #include <linux/io.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17
  18 #include "../vfio_platform_private.h"
  19
  20 /* FlexRM configuration */
  21 #define RING_REGS_SIZE                                  0x10000
  22 #define RING_VER_MAGIC                                  0x76303031
  23
  24 /* Per-Ring register offsets */
  25 #define RING_VER                                        0x000
  26 #define RING_CONTROL                                    0x034
  27 #define RING_FLUSH_DONE                                 0x038
  28
  29 /* Register RING_CONTROL fields */
  30 #define CONTROL_FLUSH_SHIFT                             5
  31
  32 /* Register RING_FLUSH_DONE fields */
  33 #define FLUSH_DONE_MASK                                 0x1
  34
  35 static int vfio_platform_bcmflexrm_shutdown(void __iomem *ring)
  36 {
  37         unsigned int timeout;
  38
  39         /* Disable/inactivate ring */
  40         writel_relaxed(0x0, ring + RING_CONTROL);
  41
  42         /* Set ring flush state */
  43         timeout = 1000; /* timeout of 1s */
  44         writel_relaxed(BIT(CONTROL_FLUSH_SHIFT), ring + RING_CONTROL);
  45         do {
  46                 if (readl_relaxed(ring + RING_FLUSH_DONE) &
  47                     FLUSH_DONE_MASK)
  48                         break;
  49                 mdelay(1);
  50         } while (--timeout);
  51         if (!timeout)
  52                 return -ETIMEDOUT;
  53
  54         /* Clear ring flush state */
  55         timeout = 1000; /* timeout of 1s */
  56         writel_relaxed(0x0, ring + RING_CONTROL);
  57         do {
  58                 if (!(readl_relaxed(ring + RING_FLUSH_DONE) &
  59                       FLUSH_DONE_MASK))
  60                         break;
  61                 mdelay(1);
  62         } while (--timeout);
  63         if (!timeout)
  64                 return -ETIMEDOUT;
  65
  66         return 0;
  67 }
  68
  69 static int vfio_platform_bcmflexrm_reset(struct vfio_platform_device *vdev)
  70 {
  71         void __iomem *ring;
  72         int rc = 0, ret = 0, ring_num = 0;
  73         struct vfio_platform_region *reg = &vdev->regions[0];
  74
  75         /* Map FlexRM ring registers if not mapped */
  76         if (!reg->ioaddr) {
  77                 reg->ioaddr = ioremap(reg->addr, reg->size);
  78                 if (!reg->ioaddr)
  79                         return -ENOMEM;
  80         }
  81
  82         /* Discover and shutdown each FlexRM ring */
  83         for (ring = reg->ioaddr;
  84              ring < (reg->ioaddr + reg->size); ring += RING_REGS_SIZE) {
  85                 if (readl_relaxed(ring + RING_VER) == RING_VER_MAGIC) {
  86                         rc = vfio_platform_bcmflexrm_shutdown(ring);
  87                         if (rc) {
  88                                 dev_warn(vdev->device,
  89                                          "FlexRM ring%d shutdown error %d\n",
  90                                          ring_num, rc);
  91                                 ret |= rc;
  92                         }
  93                         ring_num++;
  94                 }
  95         }
  96
  97         return ret;
  98 }
  99
 100 module_vfio_reset_handler("brcm,iproc-flexrm-mbox",
 101                           vfio_platform_bcmflexrm_reset);
 102
 103 MODULE_LICENSE("GPL v2");
 104 MODULE_AUTHOR("Anup Patel <anup.patel@broadcom.com>");
 105 MODULE_DESCRIPTION("Reset support for Broadcom FlexRM VFIO platform device");