arch/riscv/lib/smp.c

   1 // SPDX-License-Identifier: GPL-2.0+
   2 /*
   3  * Copyright (C) 2019 Fraunhofer AISEC,
   4  * Lukas Auer <lukas.auer@aisec.fraunhofer.de>
   5  */
   6
   7 #include <common.h>
   8 #include <cpu_func.h>
   9 #include <dm.h>
  10 #include <asm/barrier.h>
  11 #include <asm/smp.h>
  12
  13 DECLARE_GLOBAL_DATA_PTR;
  14
  15 static int send_ipi_many(struct ipi_data *ipi, int wait)
  16 {
  17         ofnode node, cpus;
  18         u32 reg;
  19         int ret, pending;
  20
  21         cpus = ofnode_path("/cpus");
  22         if (!ofnode_valid(cpus)) {
  23                 pr_err("Can't find cpus node!\n");
  24                 return -EINVAL;
  25         }
  26
  27         ofnode_for_each_subnode(node, cpus) {
  28                 /* skip if hart is marked as not available in the device tree */
  29                 if (!ofnode_is_available(node))
  30                         continue;
  31
  32                 /* read hart ID of CPU */
  33                 ret = ofnode_read_u32(node, "reg", &reg);
  34                 if (ret)
  35                         continue;
  36
  37                 /* skip if it is the hart we are running on */
  38                 if (reg == gd->arch.boot_hart)
  39                         continue;
  40
  41                 if (reg >= CONFIG_NR_CPUS) {
  42                         pr_err("Hart ID %d is out of range, increase CONFIG_NR_CPUS\n",
  43                                reg);
  44                         continue;
  45                 }
  46
  47 #ifndef CONFIG_XIP
  48                 /* skip if hart is not available */
  49                 if (!(gd->arch.available_harts & (1 << reg)))
  50                         continue;
  51 #endif
  52
  53                 gd->arch.ipi[reg].addr = ipi->addr;
  54                 gd->arch.ipi[reg].arg0 = ipi->arg0;
  55                 gd->arch.ipi[reg].arg1 = ipi->arg1;
  56
  57                 /*
  58                  * Ensure valid only becomes set when the IPI parameters are
  59                  * set. An IPI may already be pending on other harts, so we
  60                  * need a way to signal that the IPI device has been
  61                  * initialized, and that it is ok to call the function.
  62                  */
  63                 __smp_store_release(&gd->arch.ipi[reg].valid, 1);
  64
  65                 ret = riscv_send_ipi(reg);
  66                 if (ret) {
  67                         pr_err("Cannot send IPI to hart %d\n", reg);
  68                         return ret;
  69                 }
  70
  71                 if (wait) {
  72                         pending = 1;
  73                         while (pending) {
  74                                 ret = riscv_get_ipi(reg, &pending);
  75                                 if (ret)
  76                                         return ret;
  77                         }
  78                 }
  79         }
  80
  81         return 0;
  82 }
  83
  84 void handle_ipi(ulong hart)
  85 {
  86         int ret;
  87         void (*smp_function)(ulong hart, ulong arg0, ulong arg1);
  88
  89         if (hart >= CONFIG_NR_CPUS)
  90                 return;
  91
  92         /*
  93          * If valid is not set, then U-Boot has not requested the IPI. The
  94          * IPI device may not be initialized, so all we can do is wait for
  95          * U-Boot to initialize it and send an IPI
  96          */
  97         if (!__smp_load_acquire(&gd->arch.ipi[hart].valid))
  98                 return;
  99
 100         smp_function = (void (*)(ulong, ulong, ulong))gd->arch.ipi[hart].addr;
 101         invalidate_icache_all();
 102
 103         /*
 104          * Clear the IPI to acknowledge the request before jumping to the
 105          * requested function.
 106          */
 107         ret = riscv_clear_ipi(hart);
 108         if (ret) {
 109                 pr_err("Cannot clear IPI of hart %ld (error %d)\n", hart, ret);
 110                 return;
 111         }
 112
 113         smp_function(hart, gd->arch.ipi[hart].arg0, gd->arch.ipi[hart].arg1);
 114 }
 115
 116 int smp_call_function(ulong addr, ulong arg0, ulong arg1, int wait)
 117 {
 118         struct ipi_data ipi = {
 119                 .addr = addr,
 120                 .arg0 = arg0,
 121                 .arg1 = arg1,
 122         };
 123
 124         return send_ipi_many(&ipi, wait);
 125 }