[PATCH v2 5/4] ARM: footbridge: remove custom DMA address handling

Arnd Bergmann
2022-08-25T20:16:00Z

From: Arnd Bergmann <arnd@arndb.de>

Footbridge is the last Arm platform that has its own
__virt_to_bus()/__bus_to_virt()/phys_to_dma()/dma_to_phys() abstraction,
but this is just a simple offset now.

For PCI devices, the offset that is programmed into the PCI bridge must
also be set in each device using dma_direct_set_offset(). As Arm does
not have a pcibios_bus_add_device() helper yet, just use a bus notifier
for this.

For the ISA DMA, drivers now pass a non-translated physical address into
set_dma_addr(), so they have to be converted back with the corresponding
isa_bus_to_virt() function and then into the correct bus address with
the offset using the isa_dma_dev.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
v2: fix ISA DMA offset

arch/arm/include/asm/dma-direct.h | 1 -
arch/arm/include/asm/dma.h | 2 +-
arch/arm/include/asm/hardware/dec21285.h | 7 +++++++
arch/arm/include/asm/memory.h | 11 ----------
arch/arm/mach-footbridge/Kconfig | 1 -
arch/arm/mach-footbridge/common.c | 10 ---------
arch/arm/mach-footbridge/dc21285.c | 21 ++++++++++++++++++-
arch/arm/mach-footbridge/dma-isa.c | 4 ++++
.../mach-footbridge/include/mach/dma-direct.h | 8 -------
.../arm/mach-footbridge/include/mach/memory.h | 9 --------
10 files changed, 32 insertions(+), 42 deletions(-)
delete mode 100644 arch/arm/include/asm/dma-direct.h
delete mode 100644 arch/arm/mach-footbridge/include/mach/dma-direct.h

diff --git a/arch/arm/include/asm/dma-direct.h b/arch/arm/include/asm/dma-direct.h
deleted file mode 100644
index 4f7bcde03abb..000000000000
--- a/arch/arm/include/asm/dma-direct.h
+++ /dev/null
@@ -1 +0,0 @@
-#include <mach/dma-direct.h>
diff --git a/arch/arm/include/asm/dma.h b/arch/arm/include/asm/dma.h
index 05f29a72150b..c6aded1b069c 100644
--- a/arch/arm/include/asm/dma.h
+++ b/arch/arm/include/asm/dma.h
@@ -106,7 +106,7 @@ extern void set_dma_sg(unsigned int chan, struct scatterlist *sg, int nr_sg);
*/
extern void __set_dma_addr(unsigned int chan, void *addr);
#define set_dma_addr(chan, addr) \
- __set_dma_addr(chan, (void *)__bus_to_virt(addr))
+ __set_dma_addr(chan, (void *)isa_bus_to_virt(addr))

/* Set the DMA byte count for this channel
*
diff --git a/arch/arm/include/asm/hardware/dec21285.h b/arch/arm/include/asm/hardware/dec21285.h
index eee390e8d4dc..894f2a635cbb 100644
--- a/arch/arm/include/asm/hardware/dec21285.h
+++ b/arch/arm/include/asm/hardware/dec21285.h
@@ -22,6 +22,13 @@
#define DC21285_IO(x) (x)
#endif

+/*
+ * The footbridge is programmed to expose the system RAM at 0xe0000000.
+ * The requirement is that the RAM isn't placed at bus address 0, which
+ * would clash with VGA cards.
+ */
+#define BUS_OFFSET 0xe0000000
+
#define CSR_PCICMD DC21285_IO(0x0004)
#define CSR_CLASSREV DC21285_IO(0x0008)
#define CSR_PCICACHELINESIZE DC21285_IO(0x000c)
diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index a55a9038abc8..d8eef4bd8c71 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -369,17 +369,6 @@ static inline unsigned long __virt_to_idmap(unsigned long x)

#define virt_to_idmap(x) __virt_to_idmap((unsigned long)(x))

-/*
- * Virtual <-> DMA view memory address translations
- * Again, these are *only* valid on the kernel direct mapped RAM
- * memory. Use of these is *deprecated* (and that doesn't mean
- * use the __ prefixed forms instead.) See dma-mapping.h.
- */
-#ifndef __virt_to_bus
-#define __virt_to_bus __virt_to_phys
-#define __bus_to_virt __phys_to_virt
-#endif
-
/*
* Conversion between a struct page and a physical address.
*
diff --git a/arch/arm/mach-footbridge/Kconfig b/arch/arm/mach-footbridge/Kconfig
index cd18871fd03f..f452663576d1 100644
--- a/arch/arm/mach-footbridge/Kconfig
+++ b/arch/arm/mach-footbridge/Kconfig
@@ -44,7 +44,6 @@ endmenu
# Footbridge support
config FOOTBRIDGE
def_bool y
- select ARCH_HAS_PHYS_TO_DMA
select ARCH_MIGHT_HAVE_PC_SERIO
select ISA_DMA_API

diff --git a/arch/arm/mach-footbridge/common.c b/arch/arm/mach-footbridge/common.c
index 9483eccea5ae..629e4676ed77 100644
--- a/arch/arm/mach-footbridge/common.c
+++ b/arch/arm/mach-footbridge/common.c
@@ -281,13 +281,3 @@ void footbridge_restart(enum reboot_mode mode, const char *cmd)
*CSR_SA110_CNTL |= (1 << 13);
}
}
-
-dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
-{
- return paddr + (BUS_OFFSET - PHYS_OFFSET);
-}
-
-phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr)
-{
- return dev_addr - (BUS_OFFSET - PHYS_OFFSET);
-}
diff --git a/arch/arm/mach-footbridge/dc21285.c b/arch/arm/mach-footbridge/dc21285.c
index 372600bc15c8..f8920d0010de 100644
--- a/arch/arm/mach-footbridge/dc21285.c
+++ b/arch/arm/mach-footbridge/dc21285.c
@@ -5,6 +5,7 @@
* Copyright (C) 1998-2001 Russell King
* Copyright (C) 1998-2000 Phil Blundell
*/
+#include <linux/dma-map-ops.h>
#include <linux/kernel.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
@@ -241,6 +242,22 @@ static irqreturn_t dc21285_parity_irq(int irq, void *dev_id)
return IRQ_HANDLED;
}

+static int dc21285_pci_bus_notifier(struct notifier_block *nb,
+ unsigned long action,
+ void *data)
+{
+ if (action != BUS_NOTIFY_ADD_DEVICE)
+ return NOTIFY_DONE;
+
+ dma_direct_set_offset(data, PHYS_OFFSET, BUS_OFFSET, SZ_256M);
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block dc21285_pci_bus_nb = {
+ .notifier_call = dc21285_pci_bus_notifier,
+};
+
int __init dc21285_setup(int nr, struct pci_sys_data *sys)
{
struct resource *res;
@@ -266,6 +283,8 @@ int __init dc21285_setup(int nr, struct pci_sys_data *sys)
pci_add_resource_offset(&sys->resources, &res[0], sys->mem_offset);
pci_add_resource_offset(&sys->resources, &res[1], sys->mem_offset);

+ bus_register_notifier(&pci_bus_type, &dc21285_pci_bus_nb);
+
return 1;
}

@@ -329,7 +348,7 @@ void __init dc21285_preinit(void)
*/
*CSR_PCICSRBASE = 0xf4000000;
*CSR_PCICSRIOBASE = 0;
- *CSR_PCISDRAMBASE = __virt_to_bus(PAGE_OFFSET);
+ *CSR_PCISDRAMBASE = BUS_OFFSET;
*CSR_PCIROMBASE = 0;
*CSR_PCICMD = PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER |
PCI_COMMAND_INVALIDATE | PCICMD_ERROR_BITS;
diff --git a/arch/arm/mach-footbridge/dma-isa.c b/arch/arm/mach-footbridge/dma-isa.c
index 0fc0705fd58b..937f5376d5e7 100644
--- a/arch/arm/mach-footbridge/dma-isa.c
+++ b/arch/arm/mach-footbridge/dma-isa.c
@@ -11,6 +11,7 @@
* arch/arm/kernel/dma-ebsa285.c
* Copyright (C) 1998 Phil Blundell
*/
+#include <linux/dma-map-ops.h>
#include <linux/ioport.h>
#include <linux/init.h>
#include <linux/dma-mapping.h>
@@ -18,6 +19,7 @@

#include <asm/dma.h>
#include <asm/mach/dma.h>
+#include <asm/hardware/dec21285.h>

#define ISA_DMA_MASK 0
#define ISA_DMA_MODE 1
@@ -221,6 +223,8 @@ static int __init isa_dma_init(void)
request_dma(DMA_ISA_CASCADE, "cascade");
}

+ dma_direct_set_offset(&isa_dma_dev, PHYS_OFFSET, BUS_OFFSET, SZ_256M);
+
return 0;
}
core_initcall(isa_dma_init);
diff --git a/arch/arm/mach-footbridge/include/mach/dma-direct.h b/arch/arm/mach-footbridge/include/mach/dma-direct.h
deleted file mode 100644
index 01f9e8367c00..000000000000
--- a/arch/arm/mach-footbridge/include/mach/dma-direct.h
+++ /dev/null
@@ -1,8 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0 */
-#ifndef MACH_FOOTBRIDGE_DMA_DIRECT_H
-#define MACH_FOOTBRIDGE_DMA_DIRECT_H 1
-
-dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr);
-phys_addr_t dma_to_phys(struct device *dev, dma_addr_t dev_addr);
-
-#endif /* MACH_FOOTBRIDGE_DMA_DIRECT_H */
diff --git a/arch/arm/mach-footbridge/include/mach/memory.h b/arch/arm/mach-footbridge/include/mach/memory.h
index 8f0ca8e8b37e..9516877667d7 100644
--- a/arch/arm/mach-footbridge/include/mach/memory.h
+++ b/arch/arm/mach-footbridge/include/mach/memory.h
@@ -16,15 +16,6 @@
#ifndef __ASM_ARCH_MEMORY_H
#define __ASM_ARCH_MEMORY_H

-/*
- * The footbridge is programmed to expose the system RAM at 0xe0000000.
- * The requirement is that the RAM isn't placed at bus address 0, which
- * would clash with VGA cards.
- */
-#define BUS_OFFSET 0xe0000000
-#define __virt_to_bus(x) ((x) + (BUS_OFFSET - PAGE_OFFSET))
-#define __bus_to_virt(x) ((x) - (BUS_OFFSET - PAGE_OFFSET))
-
/*
* Cache flushing area.
*/
--
2.29.2