Re: [PATCH v4 3/3] irqchip: add a SiFive PLIC driver

From: kbuild test robot
Date: Thu Aug 16 2018 - 09:04:20 EST

Hi Christoph,

I love your patch! Yet something to improve:

[auto build test ERROR on tip/irq/core]
[also build test ERROR on v4.18]
[cannot apply to next-20180816]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url: https://github.com/0day-ci/linux/commits/Christoph-Hellwig/dt-bindings-interrupt-controller-RISC-V-local-interrupt-controller/20180810-014110
config: riscv-defconfig (attached as .config)
compiler: riscv64-linux-gcc (GCC) 8.1.0
reproduce:
wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
GCC_VERSION=8.1.0 make.cross ARCH=riscv

All errors (new ones prefixed by >>):

In file included from arch/riscv/include/asm/ptrace.h:18,
from arch/riscv/include/asm/processor.h:19,
from arch/riscv/include/asm/irqflags.h:18,
from include/linux/irqflags.h:16,
from arch/riscv/include/asm/bitops.h:22,
from include/linux/bitops.h:38,
from include/linux/kernel.h:11,
from include/linux/interrupt.h:6,
from drivers/irqchip/irq-sifive-plic.c:7:
drivers/irqchip/irq-sifive-plic.c: In function 'plic_handle_irq':
>> drivers/irqchip/irq-sifive-plic.c:156:17: error: 'SIE_SEIE' undeclared (first use in this function); did you mean 'SIE_STIE'?
csr_clear(sie, SIE_SEIE);
^~~~~~~~
arch/riscv/include/asm/csr.h:124:38: note: in definition of macro 'csr_clear'
unsigned long __v = (unsigned long)(val); \
^~~
drivers/irqchip/irq-sifive-plic.c:156:17: note: each undeclared identifier is reported only once for each function it appears in
csr_clear(sie, SIE_SEIE);
^~~~~~~~
arch/riscv/include/asm/csr.h:124:38: note: in definition of macro 'csr_clear'
unsigned long __v = (unsigned long)(val); \
^~~

vim +156 drivers/irqchip/irq-sifive-plic.c

> 7 #include <linux/interrupt.h>
8 #include <linux/io.h>
9 #include <linux/irq.h>
10 #include <linux/irqchip.h>
11 #include <linux/irqdomain.h>
12 #include <linux/module.h>
13 #include <linux/of.h>
14 #include <linux/of_address.h>
15 #include <linux/of_irq.h>
16 #include <linux/platform_device.h>
17 #include <linux/spinlock.h>
18
19 /*
20 * This driver implements a version of the RISC-V PLIC with the actual layout
21 * specified in chapter 8 of the SiFive U5 Coreplex Series Manual:
22 *
23 * https://static.dev.sifive.com/U54-MC-RVCoreIP.pdf
24 *
25 * The largest number supported by devices marked as 'riscv,plic0', is 1024, of
26 * which device 0 is defined as non-existent by the RISC-V Privileged Spec.
27 */
28
29 #define MAX_DEVICES 1024
30 #define MAX_CONTEXTS 15872
31
32 /*
33 * Each interrupt source has a priority register associated with it.
34 * We always hardwire it to one in Linux.
35 */
36 #define PRIORITY_BASE 0
37 #define PRIORITY_PER_ID 4
38
39 /*
40 * Each hart context has a vector of interrupt enable bits associated with it.
41 * There's one bit for each interrupt source.
42 */
43 #define ENABLE_BASE 0x2000
44 #define ENABLE_PER_HART 0x80
45
46 /*
47 * Each hart context has a set of control registers associated with it. Right
48 * now there's only two: a source priority threshold over which the hart will
49 * take an interrupt, and a register to claim interrupts.
50 */
51 #define CONTEXT_BASE 0x200000
52 #define CONTEXT_PER_HART 0x1000
53 #define CONTEXT_THRESHOLD 0x00
54 #define CONTEXT_CLAIM 0x04
55
56 static void __iomem *plic_regs;
57
58 struct plic_handler {
59 bool present;
60 int ctxid;
61 };
62 static DEFINE_PER_CPU(struct plic_handler, plic_handlers);
63
64 static inline void __iomem *plic_hart_offset(int ctxid)
65 {
66 return plic_regs + CONTEXT_BASE + ctxid * CONTEXT_PER_HART;
67 }
68
69 static inline u32 __iomem *plic_enable_base(int ctxid)
70 {
71 return plic_regs + ENABLE_BASE + ctxid * ENABLE_PER_HART;
72 }
73
74 /*
75 * Protect mask operations on the registers given that we can't assume that
76 * atomic memory operations work on them.
77 */
78 static DEFINE_RAW_SPINLOCK(plic_toggle_lock);
79
80 static inline void plic_toggle(int ctxid, int hwirq, int enable)
81 {
82 u32 __iomem *reg = plic_enable_base(ctxid) + (hwirq / 32);
83 u32 hwirq_mask = 1 << (hwirq % 32);
84
85 raw_spin_lock(&plic_toggle_lock);
86 if (enable)
87 writel(readl(reg) | hwirq_mask, reg);
88 else
89 writel(readl(reg) & ~hwirq_mask, reg);
90 raw_spin_unlock(&plic_toggle_lock);
91 }
92
93 static inline void plic_irq_toggle(struct irq_data *d, int enable)
94 {
95 int cpu;
96
97 writel(enable, plic_regs + PRIORITY_BASE + d->hwirq * PRIORITY_PER_ID);
98 for_each_cpu(cpu, irq_data_get_affinity_mask(d)) {
99 struct plic_handler *handler = per_cpu_ptr(&plic_handlers, cpu);
100
101 if (handler->present)
102 plic_toggle(handler->ctxid, d->hwirq, enable);
103 }
104 }
105
106 static void plic_irq_enable(struct irq_data *d)
107 {
108 plic_irq_toggle(d, 1);
109 }
110
111 static void plic_irq_disable(struct irq_data *d)
112 {
113 plic_irq_toggle(d, 0);
114 }
115
116 static struct irq_chip plic_chip = {
117 .name = "SiFive PLIC",
118 /*
119 * There is no need to mask/unmask PLIC interrupts. They are "masked"
120 * by reading claim and "unmasked" when writing it back.
121 */
122 .irq_enable = plic_irq_enable,
123 .irq_disable = plic_irq_disable,
124 };
125
126 static int plic_irqdomain_map(struct irq_domain *d, unsigned int irq,
127 irq_hw_number_t hwirq)
128 {
129 irq_set_chip_and_handler(irq, &plic_chip, handle_simple_irq);
130 irq_set_chip_data(irq, NULL);
131 irq_set_noprobe(irq);
132 return 0;
133 }
134
135 static const struct irq_domain_ops plic_irqdomain_ops = {
136 .map = plic_irqdomain_map,
137 .xlate = irq_domain_xlate_onecell,
138 };
139
140 static struct irq_domain *plic_irqdomain;
141
142 /*
143 * Handling an interrupt is a two-step process: first you claim the interrupt
144 * by reading the claim register, then you complete the interrupt by writing
145 * that source ID back to the same claim register. This automatically enables
146 * and disables the interrupt, so there's nothing else to do.
147 */
148 static void plic_handle_irq(struct pt_regs *regs)
149 {
150 struct plic_handler *handler = this_cpu_ptr(&plic_handlers);
151 void __iomem *claim = plic_hart_offset(handler->ctxid) + CONTEXT_CLAIM;
152 irq_hw_number_t hwirq;
153
154 WARN_ON_ONCE(!handler->present);
155
> 156 csr_clear(sie, SIE_SEIE);
157 while ((hwirq = readl(claim))) {
158 int irq = irq_find_mapping(plic_irqdomain, hwirq);
159
160 if (unlikely(irq <= 0))
161 pr_warn_ratelimited("can't find mapping for hwirq %lu\n",
162 hwirq);
163 else
164 generic_handle_irq(irq);
165 writel(hwirq, claim);
166 }
167 csr_set(sie, SIE_SEIE);
168 }
169

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