From: D Scott Phillips <scott@xxxxxxxxxxxxxxxxxxxxxx>
Altra's PCIe controller may generate incorrect addresses when receiving
writes from the CPU with a discontiguous set of byte enables. Attempt to
work around this by handing out Device-nGnRE maps instead of Normal
Non-cacheable maps for PCIe memory areas.
Upstream-Status: Pending
Signed-off-by: D Scott Phillips <scott@xxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Alex Bennée <alex.bennee@xxxxxxxxxx>
---
arch/arm64/Kconfig | 22 +++++++++++++++++++++-
arch/arm64/include/asm/io.h | 3 +++
arch/arm64/include/asm/pgtable.h | 27 ++++++++++++++++++++++-----
arch/arm64/mm/ioremap.c | 27 +++++++++++++++++++++++++++
drivers/pci/quirks.c | 9 +++++++++
include/asm-generic/io.h | 4 ++++
mm/ioremap.c | 2 +-
7 files changed, 87 insertions(+), 7 deletions(-)
diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
index b3fc891f15442..01adb50df214e 100644
--- a/arch/arm64/Kconfig
+++ b/arch/arm64/Kconfig
@@ -440,6 +440,27 @@ config AMPERE_ERRATUM_AC03_CPU_38
config ARM64_WORKAROUND_CLEAN_CACHE
bool
+config ALTRA_ERRATUM_82288
+ bool "Ampere Altra: 82288: PCIE_65: PCIe Root Port outbound write combining issue"
+ default y
+ help
+ This option adds an alternative code sequence to work around
+ Ampere Altra erratum 82288.
+
+ PCIe device drivers may map MMIO space as Normal, non-cacheable
+ memory attribute (e.g. Linux kernel drivers mapping MMIO
+ using ioremap_wc). This may be for the purpose of enabling write
+ combining or unaligned accesses. This can result in data corruption
+ on the PCIe interface’s outbound MMIO writes due to issues with the
+ write-combining operation.
+
+ The workaround modifies software that maps PCIe MMIO space as Normal,
+ non-cacheable memory (e.g. ioremap_wc) to instead Device,
+ non-gatheringmemory (e.g. ioremap). And all memory operations on PCIe
+ MMIO space must be strictly aligned.
+
+ If unsure, say Y.
+
config ARM64_ERRATUM_826319
bool "Cortex-A53: 826319: System might deadlock if a write cannot complete until read data is accepted"
default y
@@ -2388,4 +2409,3 @@ endmenu # "CPU Power Management"
source "drivers/acpi/Kconfig"
source "arch/arm64/kvm/Kconfig"
-
diff --git a/arch/arm64/include/asm/io.h b/arch/arm64/include/asm/io.h
index 41fd90895dfc3..403b65f2f44de 100644
--- a/arch/arm64/include/asm/io.h
+++ b/arch/arm64/include/asm/io.h
@@ -273,6 +273,9 @@ __iowrite64_copy(void __iomem *to, const void *from, size_t count)
#define ioremap_prot ioremap_prot
+pgprot_t ioremap_map_prot(phys_addr_t phys_addr, size_t size, unsigned long prot);
+#define ioremap_map_prot ioremap_map_prot
+
#define _PAGE_IOREMAP PROT_DEVICE_nGnRE
#define ioremap_wc(addr, size) \
diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7a4f5604be3f7..f4603924390eb 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -236,11 +236,6 @@ static inline pte_t pte_mkyoung(pte_t pte)
return set_pte_bit(pte, __pgprot(PTE_AF));
}
-static inline pte_t pte_mkspecial(pte_t pte)
-{
- return set_pte_bit(pte, __pgprot(PTE_SPECIAL));
-}
-
static inline pte_t pte_mkcont(pte_t pte)
{
pte = set_pte_bit(pte, __pgprot(PTE_CONT));
@@ -682,6 +677,28 @@ static inline bool pud_table(pud_t pud) { return true; }
PUD_TYPE_TABLE)
#endif
+#ifdef CONFIG_ALTRA_ERRATUM_82288
+extern bool __read_mostly have_altra_erratum_82288;
+#endif
+
+static inline pte_t pte_mkspecial(pte_t pte)
+{
+#ifdef CONFIG_ALTRA_ERRATUM_82288
+ phys_addr_t phys = __pte_to_phys(pte);
+ pgprot_t prot = __pgprot(pte_val(pte) & ~PTE_ADDR_LOW);
+
+ if (unlikely(have_altra_erratum_82288) &&
+ (phys < 0x80000000 ||
+ (phys >= 0x200000000000 && phys < 0x400000000000) ||
+ (phys >= 0x600000000000 && phys < 0x800000000000))) {
+ pte = __pte(__phys_to_pte_val(phys) | pgprot_val(pgprot_device(prot)));
+ }
+#endif
+
+ return set_pte_bit(pte, __pgprot(PTE_SPECIAL));
+}
+
+
extern pgd_t init_pg_dir[];
extern pgd_t init_pg_end[];
extern pgd_t swapper_pg_dir[];
diff --git a/arch/arm64/mm/ioremap.c b/arch/arm64/mm/ioremap.c
index 269f2f63ab7dc..8965766181359 100644
--- a/arch/arm64/mm/ioremap.c
+++ b/arch/arm64/mm/ioremap.c
@@ -3,6 +3,33 @@
#include <linux/mm.h>
#include <linux/io.h>
+#ifdef CONFIG_ALTRA_ERRATUM_82288
+
+bool have_altra_erratum_82288 __read_mostly;
+EXPORT_SYMBOL(have_altra_erratum_82288);
+
+static bool is_altra_pci(phys_addr_t phys_addr, size_t size)
+{
+ phys_addr_t end = phys_addr + size;
+
+ return (phys_addr < 0x80000000 ||
+ (end > 0x200000000000 && phys_addr < 0x400000000000) ||
+ (end > 0x600000000000 && phys_addr < 0x800000000000));
+}
+#endif
+
+pgprot_t ioremap_map_prot(phys_addr_t phys_addr, size_t size,
+ unsigned long prot_val)
+{
+ pgprot_t prot = __pgprot(prot_val);
+#ifdef CONFIG_ALTRA_ERRATUM_82288
+ if (unlikely(have_altra_erratum_82288 && is_altra_pci(phys_addr, size))) {
+ prot = pgprot_device(prot);
+ }
+#endif
+ return prot;
+}
+
void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
unsigned long prot)
{
diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index a2ce4e08edf5a..8baf90ee3357c 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -6234,6 +6234,15 @@ DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0xa73f, dpc_log_size);
DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0xa76e, dpc_log_size);
#endif
+#ifdef CONFIG_ALTRA_ERRATUM_82288
+static void quirk_altra_erratum_82288(struct pci_dev *dev)
+{
+ pr_info_once("Write combining PCI maps disabled due to hardware erratum\n");
+ have_altra_erratum_82288 = true;
+}
+DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_AMPERE, 0xe100, quirk_altra_erratum_82288);
+#endif
+
/*
* For a PCI device with multiple downstream devices, its driver may use
* a flattened device tree to describe the downstream devices.
diff --git a/include/asm-generic/io.h b/include/asm-generic/io.h
index 80de699bf6af4..75670d7094537 100644
--- a/include/asm-generic/io.h
+++ b/include/asm-generic/io.h
@@ -1047,6 +1047,10 @@ static inline void iounmap(volatile void __iomem *addr)
#elif defined(CONFIG_GENERIC_IOREMAP)
#include <linux/pgtable.h>
+#ifndef ioremap_map_prot
+#define ioremap_map_prot(phys_addr, size, prot) __pgprot(prot)
+#endif
+
void __iomem *generic_ioremap_prot(phys_addr_t phys_addr, size_t size,
pgprot_t prot);
diff --git a/mm/ioremap.c b/mm/ioremap.c
index 3e049dfb28bd0..a4e6950682f33 100644
--- a/mm/ioremap.c
+++ b/mm/ioremap.c
@@ -52,7 +52,7 @@ void __iomem *generic_ioremap_prot(phys_addr_t phys_addr, size_t size,
void __iomem *ioremap_prot(phys_addr_t phys_addr, size_t size,
unsigned long prot)
{
- return generic_ioremap_prot(phys_addr, size, __pgprot(prot));
+ return generic_ioremap_prot(phys_addr, size, ioremap_map_prot(phys_addr, size, prot));
}
EXPORT_SYMBOL(ioremap_prot);
#endif
--
2.39.2
