src/soc/intel/common/block/systemagent-server/common.c

   1 /* SPDX-License-Identifier: GPL-2.0-only */
   2
   3 #define __SIMPLE_DEVICE__
   4
   5 #include <device/pci_ops.h>
   6 #include <intelblocks/systemagent_server.h>
   7
   8 static uint32_t pci_moving_config32(pci_devfn_t dev, unsigned int reg)
   9 {
  10         uint32_t value, ones, zeroes;
  11
  12         value = pci_read_config32(dev, reg);
  13
  14         pci_write_config32(dev, reg, 0xffffffff);
  15         ones = pci_read_config32(dev, reg);
  16
  17         pci_write_config32(dev, reg, 0x00000000);
  18         zeroes = pci_read_config32(dev, reg);
  19
  20         pci_write_config32(dev, reg, value);
  21
  22         return ones ^ zeroes;
  23 }
  24
  25 uint64_t sa_server_read_map_entry(pci_devfn_t dev,
  26                                   const struct sa_server_mem_map_descriptor *entry)
  27 {
  28         uint64_t value = 0;
  29         uint32_t alignment = entry->alignment;
  30
  31         if (entry->is_64_bit) {
  32                 value = pci_s_read_config32(dev, entry->reg_offset + 4);
  33                 value <<= 32;
  34         }
  35
  36         value |= pci_s_read_config32(dev, entry->reg_offset);
  37
  38         /**
  39          * Probe the alignment if not provided, promising the lower bits are read only, otherwise
  40          * SoC should give a initial value.
  41          */
  42         if (!alignment)
  43                 alignment = ~pci_moving_config32(dev, entry->reg_offset) + 1;
  44
  45         /**
  46          * If register stores the limit address, where lower bits are read as 0s but treated as 1s,
  47          * restore the lower bits and align it up.
  48          */
  49         if (entry->is_limit)
  50                 value = ALIGN_UP(value + alignment - 1, alignment);
  51         else
  52                 value = ALIGN_DOWN(value, alignment);
  53
  54         return value;
  55 }