sysdev/xics/icp-hv.c

0001 // SPDX-License-Identifier: GPL-2.0-or-later
0002 /*
0003  * Copyright 2011 IBM Corporation.
0004  */
0005 #include <linux/types.h>
0006 #include <linux/kernel.h>
0007 #include <linux/irq.h>
0008 #include <linux/smp.h>
0009 #include <linux/interrupt.h>
0010 #include <linux/irqdomain.h>
0011 #include <linux/cpu.h>
0012 #include <linux/of.h>
0013
0014 #include <asm/smp.h>
0015 #include <asm/irq.h>
0016 #include <asm/errno.h>
0017 #include <asm/xics.h>
0018 #include <asm/io.h>
0019 #include <asm/hvcall.h>
0020
0021 static inline unsigned int icp_hv_get_xirr(unsigned char cppr)
0022 {
0023     unsigned long retbuf[PLPAR_HCALL_BUFSIZE];
0024     long rc;
0025     unsigned int ret = XICS_IRQ_SPURIOUS;
0026
0027     rc = plpar_hcall(H_XIRR, retbuf, cppr);
0028     if (rc == H_SUCCESS) {
0029         ret = (unsigned int)retbuf[0];
0030     } else {
0031         pr_err("%s: bad return code xirr cppr=0x%x returned %ld\n",
0032             __func__, cppr, rc);
0033         WARN_ON_ONCE(1);
0034     }
0035
0036     return ret;
0037 }
0038
0039 static inline void icp_hv_set_cppr(u8 value)
0040 {
0041     long rc = plpar_hcall_norets(H_CPPR, value);
0042     if (rc != H_SUCCESS) {
0043         pr_err("%s: bad return code cppr cppr=0x%x returned %ld\n",
0044             __func__, value, rc);
0045         WARN_ON_ONCE(1);
0046     }
0047 }
0048
0049 static inline void icp_hv_set_xirr(unsigned int value)
0050 {
0051     long rc = plpar_hcall_norets(H_EOI, value);
0052     if (rc != H_SUCCESS) {
0053         pr_err("%s: bad return code eoi xirr=0x%x returned %ld\n",
0054             __func__, value, rc);
0055         WARN_ON_ONCE(1);
0056         icp_hv_set_cppr(value >> 24);
0057     }
0058 }
0059
0060 static inline void icp_hv_set_qirr(int n_cpu , u8 value)
0061 {
0062     int hw_cpu = get_hard_smp_processor_id(n_cpu);
0063     long rc;
0064
0065     /* Make sure all previous accesses are ordered before IPI sending */
0066     mb();
0067     rc = plpar_hcall_norets(H_IPI, hw_cpu, value);
0068     if (rc != H_SUCCESS) {
0069         pr_err("%s: bad return code qirr cpu=%d hw_cpu=%d mfrr=0x%x "
0070             "returned %ld\n", __func__, n_cpu, hw_cpu, value, rc);
0071         WARN_ON_ONCE(1);
0072     }
0073 }
0074
0075 static void icp_hv_eoi(struct irq_data *d)
0076 {
0077     unsigned int hw_irq = (unsigned int)irqd_to_hwirq(d);
0078
0079     iosync();
0080     icp_hv_set_xirr((xics_pop_cppr() << 24) | hw_irq);
0081 }
0082
0083 static void icp_hv_teardown_cpu(void)
0084 {
0085     int cpu = smp_processor_id();
0086
0087     /* Clear any pending IPI */
0088     icp_hv_set_qirr(cpu, 0xff);
0089 }
0090
0091 static void icp_hv_flush_ipi(void)
0092 {
0093     /* We take the ipi irq but and never return so we
0094      * need to EOI the IPI, but want to leave our priority 0
0095      *
0096      * should we check all the other interrupts too?
0097      * should we be flagging idle loop instead?
0098      * or creating some task to be scheduled?
0099      */
0100
0101     icp_hv_set_xirr((0x00 << 24) | XICS_IPI);
0102 }
0103
0104 static unsigned int icp_hv_get_irq(void)
0105 {
0106     unsigned int xirr = icp_hv_get_xirr(xics_cppr_top());
0107     unsigned int vec = xirr & 0x00ffffff;
0108     unsigned int irq;
0109
0110     if (vec == XICS_IRQ_SPURIOUS)
0111         return 0;
0112
0113     irq = irq_find_mapping(xics_host, vec);
0114     if (likely(irq)) {
0115         xics_push_cppr(vec);
0116         return irq;
0117     }
0118
0119     /* We don't have a linux mapping, so have rtas mask it. */
0120     xics_mask_unknown_vec(vec);
0121
0122     /* We might learn about it later, so EOI it */
0123     icp_hv_set_xirr(xirr);
0124
0125     return 0;
0126 }
0127
0128 static void icp_hv_set_cpu_priority(unsigned char cppr)
0129 {
0130     xics_set_base_cppr(cppr);
0131     icp_hv_set_cppr(cppr);
0132     iosync();
0133 }
0134
0135 #ifdef CONFIG_SMP
0136
0137 static void icp_hv_cause_ipi(int cpu)
0138 {
0139     icp_hv_set_qirr(cpu, IPI_PRIORITY);
0140 }
0141
0142 static irqreturn_t icp_hv_ipi_action(int irq, void *dev_id)
0143 {
0144     int cpu = smp_processor_id();
0145
0146     icp_hv_set_qirr(cpu, 0xff);
0147
0148     return smp_ipi_demux();
0149 }
0150
0151 #endif /* CONFIG_SMP */
0152
0153 static const struct icp_ops icp_hv_ops = {
0154     .get_irq    = icp_hv_get_irq,
0155     .eoi        = icp_hv_eoi,
0156     .set_priority   = icp_hv_set_cpu_priority,
0157     .teardown_cpu   = icp_hv_teardown_cpu,
0158     .flush_ipi  = icp_hv_flush_ipi,
0159 #ifdef CONFIG_SMP
0160     .ipi_action = icp_hv_ipi_action,
0161     .cause_ipi  = icp_hv_cause_ipi,
0162 #endif
0163 };
0164
0165 int __init icp_hv_init(void)
0166 {
0167     struct device_node *np;
0168
0169     np = of_find_compatible_node(NULL, NULL, "ibm,ppc-xicp");
0170     if (!np)
0171         np = of_find_node_by_type(NULL,
0172                     "PowerPC-External-Interrupt-Presentation");
0173     if (!np)
0174         return -ENODEV;
0175
0176     icp_ops = &icp_hv_ops;
0177
0178     of_node_put(np);
0179     return 0;
0180 }
0181