ARM: footbridge: remove custom DMA address handling

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.
Tested-by: Marc Zyngier <maz@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/include/asm/dma-direct.h

-#include <mach/dma-direct.h>

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
  *

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)

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.
  *

arch/arm/mach-footbridge/Kconfig

@@ -46,7 +46,6 @@ endmenu
 # Footbridge support
 config FOOTBRIDGE
 	def_bool y
-	select ARCH_HAS_PHYS_TO_DMA
 	select ARCH_MIGHT_HAVE_PC_SERIO
 	select ISA_DMA_API
 

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);
-}

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;

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);

arch/arm/mach-footbridge/include/mach/dma-direct.h

-/* 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 */

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.
  */