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[RFC,v5.1,3/9] riscv: errata: Add Andes alternative ports

Message ID 20230103210400.3500626-4-conor@kernel.org (mailing list archive)
State Changes Requested
Headers show
Series Generic function based cache management operations (was Re: [PATCH v5 6/6] soc: renesas: Add L2 cache management for RZ/Five SoC) | expand

Commit Message

Conor Dooley Jan. 3, 2023, 9:03 p.m. UTC 
From: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>

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

I/O Coherence Port (IOCP) provides an AXI interface for connecting external
non-caching masters, such as DMA controllers. IOCP is a specification
option and is disabled on the Renesas RZ/Five SoC due to this reason cache
management needs a software workaround.

Signed-off-by: Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>
Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 arch/riscv/Kconfig.erratas           | 22 +++++++
 arch/riscv/errata/Makefile           |  1 +
 arch/riscv/errata/andes/Makefile     |  1 +
 arch/riscv/errata/andes/errata.c     | 93 ++++++++++++++++++++++++++++
 arch/riscv/include/asm/alternative.h |  3 +
 arch/riscv/include/asm/errata_list.h |  5 ++
 arch/riscv/kernel/alternative.c      |  5 ++
 7 files changed, 130 insertions(+)
 create mode 100644 arch/riscv/errata/andes/Makefile
 create mode 100644 arch/riscv/errata/andes/errata.c
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Patch

diff --git a/arch/riscv/Kconfig.erratas b/arch/riscv/Kconfig.erratas
index 69621ae6d647..f0f0c1abd52b 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 && ARCH_R9A07G043
+	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..6f1c693af92d 100644
--- a/arch/riscv/errata/Makefile
+++ b/arch/riscv/errata/Makefile
@@ -1,2 +1,3 @@ 
+obj-$(CONFIG_ERRATA_ANDES) += andes/
 obj-$(CONFIG_ERRATA_SIFIVE) += sifive/
 obj-$(CONFIG_ERRATA_THEAD) += thead/
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..3d04f15df8d5
--- /dev/null
+++ b/arch/riscv/errata/andes/errata.c
@@ -0,0 +1,93 @@ 
+// 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/sbi.h>
+#include <asm/vendorid_list.h>
+
+#define ANDESTECH_AX45MP_MARCHID	0x8000000000008a45UL
+#define ANDESTECH_AX45MP_MIMPID		0x500UL
+#define ANDESTECH_SBI_EXT_ANDES		0x0900031E
+
+#define RZFIVE_SBI_EXT_IOCP_SW_WORKAROUND	0
+
+static long ax45mp_iocp_sw_workaround(void)
+{
+	struct sbiret ret;
+
+	ret = sbi_ecall(ANDESTECH_SBI_EXT_ANDES, RZFIVE_SBI_EXT_IOCP_SW_WORKAROUND,
+			0, 0, 0, 0, 0, 0);
+
+	return ret.error ? 0 : ret.value;
+}
+
+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 != ANDESTECH_AX45MP_MARCHID || impid != ANDESTECH_AX45MP_MIMPID)
+		return false;
+
+	if (!ax45mp_iocp_sw_workaround())
+		return false;
+
+	/* Set this just to make core cbo code happy */
+	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;
+
+	/*
+	 * In the absence of the I/O Coherency Port, access to certain peripherals
+	 * requires vendor specific DMA handling.
+	 */
+	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 = BIT(alt->errata_id);
+		if (cpu_req_errata & tmp) {
+			patch_text_nosync(alt->old_ptr, alt->alt_ptr, alt->alt_len);
+
+			riscv_alternative_fix_offsets(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 1bd4027d34ca..e3a8e603eb5a 100644
--- a/arch/riscv/include/asm/alternative.h
+++ b/arch/riscv/include/asm/alternative.h
@@ -43,6 +43,9 @@  struct errata_checkfunc_id {
 	bool (*func)(struct alt_entry *alt);
 };
 
+void andes_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
+			     unsigned long archid, unsigned long impid,
+			     unsigned int stage);
 void sifive_errata_patch_func(struct alt_entry *begin, struct alt_entry *end,
 			      unsigned long archid, unsigned long impid,
 			      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 6212ea0eed72..d7027a977ee6 100644
--- a/arch/riscv/kernel/alternative.c
+++ b/arch/riscv/kernel/alternative.c
@@ -40,6 +40,11 @@  static void __init_or_module riscv_fill_cpu_mfr_info(struct cpu_manufacturer_inf
 #endif
 
 	switch (cpu_mfr_info->vendor_id) {
+#ifdef CONFIG_ERRATA_ANDES
+	case ANDESTECH_VENDOR_ID:
+		cpu_mfr_info->patch_func = andes_errata_patch_func;
+		break;
+#endif
 #ifdef CONFIG_ERRATA_SIFIVE
 	case SIFIVE_VENDOR_ID:
 		cpu_mfr_info->patch_func = sifive_errata_patch_func;