riscv: Add a SYSCON driver for Andestech's PLIC

The Platform-Level Interrupt Controller (PLIC)
block holds memory-mapped claim and pending registers
associated with software interrupt. It is required
for handling IPI.

Signed-off-by: Rick Chen <rick@andestech.com>
Cc: Greentime Hu <greentime@andestech.com>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>
Reviewed-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>

diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 3a4470d..511768b 100644 (file)
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -109,6 +109,15 @@ config SIFIVE_CLINT
          The SiFive CLINT block holds memory-mapped control and status registers
          associated with software and timer interrupts.
 
+config ANDES_PLIC
+       bool
+       depends on RISCV_MMODE
+       select REGMAP
+       select SYSCON
+       help
+         The Andes PLIC block holds memory-mapped claim and pending registers
+         associated with software interrupt.
+
 config RISCV_RDTIME
        bool
        default y if RISCV_SMODE

diff --git a/arch/riscv/include/asm/global_data.h b/arch/riscv/include/asm/global_data.h
index 80e3165..b867910 100644 (file)
--- a/arch/riscv/include/asm/global_data.h
+++ b/arch/riscv/include/asm/global_data.h
@@ -18,6 +18,9 @@ struct arch_global_data {
 #ifdef CONFIG_SIFIVE_CLINT
        void __iomem *clint;    /* clint base address */
 #endif
+#ifdef CONFIG_ANDES_PLIC
+       void __iomem *plic;     /* plic base address */
+#endif
 #ifdef CONFIG_SMP
        struct ipi_data ipi[CONFIG_NR_CPUS];
 #endif

diff --git a/arch/riscv/include/asm/syscon.h b/arch/riscv/include/asm/syscon.h
index d311ee6..a086208 100644 (file)
--- a/arch/riscv/include/asm/syscon.h
+++ b/arch/riscv/include/asm/syscon.h
@@ -8,12 +8,11 @@
 
 /*
  * System controllers in a RISC-V system
- *
- * So far only SiFive's Core Local Interruptor (CLINT) is defined.
  */
 enum {
        RISCV_NONE,
        RISCV_SYSCON_CLINT,     /* Core Local Interruptor (CLINT) */
+       RISCV_SYSCON_PLIC,      /* Platform Level Interrupt Controller (PLIC) */
 };
 
 #endif /* _ASM_SYSCON_H */

diff --git a/arch/riscv/lib/Makefile b/arch/riscv/lib/Makefile
index 35dbf64..1bf554b 100644 (file)
--- a/arch/riscv/lib/Makefile
+++ b/arch/riscv/lib/Makefile
@@ -11,6 +11,7 @@ obj-$(CONFIG_CMD_GO) += boot.o
 obj-y  += cache.o
 obj-$(CONFIG_RISCV_RDTIME) += rdtime.o
 obj-$(CONFIG_SIFIVE_CLINT) += sifive_clint.o
+obj-$(CONFIG_ANDES_PLIC) += andes_plic.o
 obj-y  += interrupts.o
 obj-y  += reset.o
 obj-$(CONFIG_SBI_IPI) += sbi_ipi.o

diff --git a/arch/riscv/lib/andes_plic.c b/arch/riscv/lib/andes_plic.c
new file mode 100644 (file)
index 0000000..2ffe49a
--- /dev/null
+++ b/arch/riscv/lib/andes_plic.c
@@ -0,0 +1,113 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2019, Rick Chen <rick@andestech.com>
+ *
+ * U-Boot syscon driver for Andes's Platform Level Interrupt Controller (PLIC).
+ * The PLIC block holds memory-mapped claim and pending registers
+ * associated with software interrupt.
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <dm/device-internal.h>
+#include <dm/lists.h>
+#include <dm/uclass-internal.h>
+#include <regmap.h>
+#include <syscon.h>
+#include <asm/io.h>
+#include <asm/syscon.h>
+#include <cpu.h>
+
+/* pending register */
+#define PENDING_REG(base, hart)        ((ulong)(base) + 0x1000 + (hart) * 8)
+/* enable register */
+#define ENABLE_REG(base, hart) ((ulong)(base) + 0x2000 + (hart) * 0x80)
+/* claim register */
+#define CLAIM_REG(base, hart)  ((ulong)(base) + 0x200004 + (hart) * 0x1000)
+
+#define ENABLE_HART_IPI         (0x80808080)
+#define SEND_IPI_TO_HART(hart)  (0x80 >> (hart))
+
+DECLARE_GLOBAL_DATA_PTR;
+static int init_plic(void);
+
+#define PLIC_BASE_GET(void)                                            \
+       do {                                                            \
+               long *ret;                                              \
+                                                                       \
+               if (!gd->arch.plic) {                                   \
+                       ret = syscon_get_first_range(RISCV_SYSCON_PLIC); \
+                       if (IS_ERR(ret))                                \
+                               return PTR_ERR(ret);                    \
+                       gd->arch.plic = ret;                            \
+                       init_plic();                                    \
+               }                                                       \
+       } while (0)
+
+static int enable_ipi(int harts)
+{
+       int i;
+       int en = ENABLE_HART_IPI;
+
+       for (i = 0; i < harts; i++) {
+               en = en >> i;
+               writel(en, (void __iomem *)ENABLE_REG(gd->arch.plic, i));
+       }
+
+       return 0;
+}
+
+static int init_plic(void)
+{
+       struct udevice *dev;
+       int ret;
+
+       ret = uclass_find_first_device(UCLASS_CPU, &dev);
+       if (ret)
+               return ret;
+
+       if (ret == 0 && dev) {
+               ret = cpu_get_count(dev);
+               if (ret < 0)
+                       return ret;
+
+               enable_ipi(ret);
+               return 0;
+       }
+
+       return -ENODEV;
+}
+
+int riscv_send_ipi(int hart)
+{
+       PLIC_BASE_GET();
+
+       writel(SEND_IPI_TO_HART(hart),
+              (void __iomem *)PENDING_REG(gd->arch.plic, gd->arch.boot_hart));
+
+       return 0;
+}
+
+int riscv_clear_ipi(int hart)
+{
+       u32 source_id;
+
+       PLIC_BASE_GET();
+
+       source_id = readl((void __iomem *)CLAIM_REG(gd->arch.plic, hart));
+       writel(source_id, (void __iomem *)CLAIM_REG(gd->arch.plic, hart));
+
+       return 0;
+}
+
+static const struct udevice_id andes_plic_ids[] = {
+       { .compatible = "riscv,plic1", .data = RISCV_SYSCON_PLIC },
+       { }
+};
+
+U_BOOT_DRIVER(andes_plic) = {
+       .name           = "andes_plic",
+       .id             = UCLASS_SYSCON,
+       .of_match       = andes_plic_ids,
+       .flags          = DM_FLAG_PRE_RELOC,
+};