[PATCH v4 3/7] riscv: errata: Add Andes alternative ports

Prabhakar
2022-11-24T17:23:23Z

From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

Add required ports of the Alternative scheme for Andes CPU cores.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
---
RFC v3 -> v4
* New patch
---
arch/riscv/Kconfig.erratas | 22 +++++++++
arch/riscv/errata/Makefile | 1 +
arch/riscv/errata/andes/Makefile | 1 +
arch/riscv/errata/andes/errata.c | 68 ++++++++++++++++++++++++++++
arch/riscv/include/asm/alternative.h | 3 ++
arch/riscv/include/asm/errata_list.h | 5 ++
arch/riscv/kernel/alternative.c | 5 ++
7 files changed, 105 insertions(+)
create mode 100644 arch/riscv/errata/andes/Makefile
create mode 100644 arch/riscv/errata/andes/errata.c

diff --git a/arch/riscv/Kconfig.erratas b/arch/riscv/Kconfig.erratas
index 69621ae6d647..74b44e5dd710 100644
--- a/arch/riscv/Kconfig.erratas
+++ b/arch/riscv/Kconfig.erratas
@@ -1,5 +1,27 @@
menu "CPU errata selection"

+config ERRATA_ANDES
+ bool "Andes AX45MP errata"
+ depends on !XIP_KERNEL
+ select RISCV_ALTERNATIVE
+ help
+ All Andes errata Kconfig depend on this Kconfig. Disabling
+ this Kconfig will disable all Andes errata. Please say "Y"
+ here if your platform uses Andes CPU cores.
+
+ Otherwise, please say "N" here to avoid unnecessary overhead.
+
+config ERRATA_ANDES_CMO
+ bool "Apply Andes cache management errata"
+ depends on ERRATA_ANDES && MMU
+ select RISCV_DMA_NONCOHERENT
+ default y
+ help
+ This will apply the cache management errata to handle the
+ non-standard handling on non-coherent operations on Andes cores.
+
+ If you don't know what to do here, say "Y".
+
config ERRATA_SIFIVE
bool "SiFive errata"
depends on !XIP_KERNEL
diff --git a/arch/riscv/errata/Makefile b/arch/riscv/errata/Makefile
index a1055965fbee..81828e80f6dc 100644
--- a/arch/riscv/errata/Makefile
+++ b/arch/riscv/errata/Makefile
@@ -1,2 +1,3 @@
obj-$(CONFIG_ERRATA_SIFIVE) += sifive/
obj-$(CONFIG_ERRATA_THEAD) += thead/
+obj-$(CONFIG_ERRATA_ANDES) += andes/
diff --git a/arch/riscv/errata/andes/Makefile b/arch/riscv/errata/andes/Makefile
new file mode 100644
index 000000000000..2d644e19caef
--- /dev/null
+++ b/arch/riscv/errata/andes/Makefile
@@ -0,0 +1 @@
+obj-y += errata.o
diff --git a/arch/riscv/errata/andes/errata.c b/arch/riscv/errata/andes/errata.c
new file mode 100644
index 000000000000..ec3e052ca8c7
--- /dev/null
+++ b/arch/riscv/errata/andes/errata.c
@@ -0,0 +1,68 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Erratas to be applied for Andes CPU cores
+ *
+ * Copyright (C) 2022 Renesas Electronics Corporation.
+ *
+ * Author: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+
+#include <asm/alternative.h>
+#include <asm/cacheflush.h>
+#include <asm/errata_list.h>
+#include <asm/patch.h>
+#include <asm/vendorid_list.h>
+
+static bool errata_probe_iocp(unsigned int stage, unsigned long arch_id, unsigned long impid)
+{
+ if (!IS_ENABLED(CONFIG_ERRATA_ANDES_CMO))
+ return false;
+
+ if (arch_id != 0x8000000000008a45 || impid != 0x500)
+ return false;
+
+ riscv_cbom_block_size = 1;
+ riscv_noncoherent_supported();
+
+ return true;
+}
+
+static u32 andes_errata_probe(unsigned int stage, unsigned long archid, unsigned long impid)
+{
+ u32 cpu_req_errata = 0;
+
+ if (errata_probe_iocp(stage, archid, impid))
+ cpu_req_errata |= BIT(ERRATA_ANDESTECH_NO_IOCP);
+
+ return cpu_req_errata;
+}
+
+void __init_or_module andes_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+ unsigned long archid, unsigned long impid,
+ unsigned int stage)
+{
+ u32 cpu_req_errata = andes_errata_probe(stage, archid, impid);
+ struct alt_entry *alt;
+ u32 tmp;
+
+ if (stage == RISCV_ALTERNATIVES_EARLY_BOOT)
+ return;
+
+ for (alt = begin; alt < end; alt++) {
+ if (alt->vendor_id != ANDESTECH_VENDOR_ID)
+ continue;
+ if (alt->errata_id >= ERRATA_ANDESTECH_NUMBER)
+ continue;
+
+ tmp = (1U << alt->errata_id);
+ if (cpu_req_errata & tmp) {
+ patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
+
+ riscv_alternative_fix_auipc_jalr(alt->old_ptr, alt->alt_len,
+ alt->old_ptr - alt->alt_ptr);
+ }
+ }
+}
diff --git a/arch/riscv/include/asm/alternative.h b/arch/riscv/include/asm/alternative.h
index 6511dd73e812..d8012af30cbd 100644
--- a/arch/riscv/include/asm/alternative.h
+++ b/arch/riscv/include/asm/alternative.h
@@ -46,6 +46,9 @@ void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
void thead_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
unsigned long archid, unsigned long impid,
unsigned int stage);
+void andes_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+ unsigned long archid, unsigned long impid,
+ unsigned int stage);

void riscv_cpufeature_patch_func(struct alt_entry *begin, struct alt_entry *end,
unsigned int stage);
diff --git a/arch/riscv/include/asm/errata_list.h b/arch/riscv/include/asm/errata_list.h
index 4180312d2a70..2ba7e6e74540 100644
--- a/arch/riscv/include/asm/errata_list.h
+++ b/arch/riscv/include/asm/errata_list.h
@@ -9,6 +9,11 @@
#include <asm/csr.h>
#include <asm/vendorid_list.h>

+#ifdef CONFIG_ERRATA_ANDES
+#define ERRATA_ANDESTECH_NO_IOCP 0
+#define ERRATA_ANDESTECH_NUMBER 1
+#endif
+
#ifdef CONFIG_ERRATA_SIFIVE
#define ERRATA_SIFIVE_CIP_453 0
#define ERRATA_SIFIVE_CIP_1200 1
diff --git a/arch/riscv/kernel/alternative.c b/arch/riscv/kernel/alternative.c
index a7d26a00beea..4ded3e9aa3bc 100644
--- a/arch/riscv/kernel/alternative.c
+++ b/arch/riscv/kernel/alternative.c
@@ -47,6 +47,11 @@ static void __init_or_module riscv_fill_cpu_mfr_info(struct cpu_manufacturer_inf
case THEAD_VENDOR_ID:
cpu_mfr_info->patch_func = thead_errata_patch_func;
break;
+#endif
+#ifdef CONFIG_ERRATA_ANDES
+ case ANDESTECH_VENDOR_ID:
+ cpu_mfr_info->patch_func = andes_errata_patch_func;
+ break;
#endif
default:
cpu_mfr_info->patch_func = NULL;
--
2.25.1