Merge tag 'asm-generic-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic

Pull asm-generic updates from Arnd Bergmann:
 "There are three independent sets of changes:

   - Sai Prakash Ranjan adds tracing support to the asm-generic version
     of the MMIO accessors, which is intended to help understand
     problems with device drivers and has been part of Qualcomm's vendor
     kernels for many years

   - A patch from Sebastian Siewior to rework the handling of IRQ stacks
     in softirqs across architectures, which is needed for enabling
     PREEMPT_RT

   - The last patch to remove the CONFIG_VIRT_TO_BUS option and some of
     the code behind that, after the last users of this old interface
     made it in through the netdev, scsi, media and staging trees"

* tag 'asm-generic-6.0' of git://git.kernel.org/pub/scm/linux/kernel/git/arnd/asm-generic:
  uapi: asm-generic: fcntl: Fix typo 'the the' in comment
  arch/*/: remove CONFIG_VIRT_TO_BUS
  soc: qcom: geni: Disable MMIO tracing for GENI SE
  serial: qcom_geni_serial: Disable MMIO tracing for geni serial
  asm-generic/io: Add logging support for MMIO accessors
  KVM: arm64: Add a flag to disable MMIO trace for nVHE KVM
  lib: Add register read/write tracing support
  drm/meson: Fix overflow implicit truncation warnings
  irqchip/tegra: Fix overflow implicit truncation warnings
  coresight: etm4x: Use asm-generic IO memory barriers
  arm64: io: Use asm-generic high level MMIO accessors
  arch/*: Disable softirq stacks on PREEMPT_RT.

3 files changed, 0 insertions, 235 deletions

diff --git a/Documentation/core-api/bus-virt-phys-mapping.rst b/Documentation/core-api/bus-virt-phys-mapping.rst
deleted file mode 100644
index c72b24a7d52c..000000000000
--- a/Documentation/core-api/bus-virt-phys-mapping.rst
+++ /dev/null
@@ -1,220 +0,0 @@
-==========================================================
-How to access I/O mapped memory from within device drivers
-==========================================================
-
-:Author: Linus
-
-.. warning::
-
-	The virt_to_bus() and bus_to_virt() functions have been
-	superseded by the functionality provided by the PCI DMA interface
-	(see Documentation/core-api/dma-api-howto.rst).  They continue
-	to be documented below for historical purposes, but new code
-	must not use them. --davidm 00/12/12
-
-::
-
-  [ This is a mail message in response to a query on IO mapping, thus the
-    strange format for a "document" ]
-
-The AHA-1542 is a bus-master device, and your patch makes the driver give the
-controller the physical address of the buffers, which is correct on x86
-(because all bus master devices see the physical memory mappings directly). 
-
-However, on many setups, there are actually **three** different ways of looking
-at memory addresses, and in this case we actually want the third, the
-so-called "bus address". 
-
-Essentially, the three ways of addressing memory are (this is "real memory",
-that is, normal RAM--see later about other details): 
-
- - CPU untranslated.  This is the "physical" address.  Physical address 
-   0 is what the CPU sees when it drives zeroes on the memory bus.
-
- - CPU translated address. This is the "virtual" address, and is 
-   completely internal to the CPU itself with the CPU doing the appropriate
-   translations into "CPU untranslated". 
-
- - bus address. This is the address of memory as seen by OTHER devices, 
-   not the CPU. Now, in theory there could be many different bus 
-   addresses, with each device seeing memory in some device-specific way, but
-   happily most hardware designers aren't actually actively trying to make
-   things any more complex than necessary, so you can assume that all 
-   external hardware sees the memory the same way. 
-
-Now, on normal PCs the bus address is exactly the same as the physical
-address, and things are very simple indeed. However, they are that simple
-because the memory and the devices share the same address space, and that is
-not generally necessarily true on other PCI/ISA setups. 
-
-Now, just as an example, on the PReP (PowerPC Reference Platform), the 
-CPU sees a memory map something like this (this is from memory)::
-
-	0-2 GB		"real memory"
-	2 GB-3 GB	"system IO" (inb/out and similar accesses on x86)
-	3 GB-4 GB 	"IO memory" (shared memory over the IO bus)
-
-Now, that looks simple enough. However, when you look at the same thing from
-the viewpoint of the devices, you have the reverse, and the physical memory
-address 0 actually shows up as address 2 GB for any IO master.
-
-So when the CPU wants any bus master to write to physical memory 0, it 
-has to give the master address 0x80000000 as the memory address.
-
-So, for example, depending on how the kernel is actually mapped on the 
-PPC, you can end up with a setup like this::
-
- physical address:	0
- virtual address:	0xC0000000
- bus address:		0x80000000
-
-where all the addresses actually point to the same thing.  It's just seen 
-through different translations..
-
-Similarly, on the Alpha, the normal translation is::
-
- physical address:	0
- virtual address:	0xfffffc0000000000
- bus address:		0x40000000
-
-(but there are also Alphas where the physical address and the bus address
-are the same). 
-
-Anyway, the way to look up all these translations, you do::
-
-	#include <asm/io.h>
-
-	phys_addr = virt_to_phys(virt_addr);
-	virt_addr = phys_to_virt(phys_addr);
-	 bus_addr = virt_to_bus(virt_addr);
-	virt_addr = bus_to_virt(bus_addr);
-
-Now, when do you need these?
-
-You want the **virtual** address when you are actually going to access that
-pointer from the kernel. So you can have something like this::
-
-	/*
-	 * this is the hardware "mailbox" we use to communicate with
-	 * the controller. The controller sees this directly.
-	 */
-	struct mailbox {
-		__u32 status;
-		__u32 bufstart;
-		__u32 buflen;
-		..
-	} mbox;
-
-		unsigned char * retbuffer;
-
-		/* get the address from the controller */
-		retbuffer = bus_to_virt(mbox.bufstart);
-		switch (retbuffer[0]) {
-			case STATUS_OK:
-				...
-
-on the other hand, you want the bus address when you have a buffer that 
-you want to give to the controller::
-
-	/* ask the controller to read the sense status into "sense_buffer" */
-	mbox.bufstart = virt_to_bus(&sense_buffer);
-	mbox.buflen = sizeof(sense_buffer);
-	mbox.status = 0;
-	notify_controller(&mbox);
-
-And you generally **never** want to use the physical address, because you can't
-use that from the CPU (the CPU only uses translated virtual addresses), and
-you can't use it from the bus master. 
-
-So why do we care about the physical address at all? We do need the physical
-address in some cases, it's just not very often in normal code.  The physical
-address is needed if you use memory mappings, for example, because the
-"remap_pfn_range()" mm function wants the physical address of the memory to
-be remapped as measured in units of pages, a.k.a. the pfn (the memory
-management layer doesn't know about devices outside the CPU, so it
-shouldn't need to know about "bus addresses" etc).
-
-.. note::
-
-	The above is only one part of the whole equation. The above
-	only talks about "real memory", that is, CPU memory (RAM).
-
-There is a completely different type of memory too, and that's the "shared
-memory" on the PCI or ISA bus. That's generally not RAM (although in the case
-of a video graphics card it can be normal DRAM that is just used for a frame
-buffer), but can be things like a packet buffer in a network card etc. 
-
-This memory is called "PCI memory" or "shared memory" or "IO memory" or
-whatever, and there is only one way to access it: the readb/writeb and
-related functions. You should never take the address of such memory, because
-there is really nothing you can do with such an address: it's not
-conceptually in the same memory space as "real memory" at all, so you cannot
-just dereference a pointer. (Sadly, on x86 it **is** in the same memory space,
-so on x86 it actually works to just deference a pointer, but it's not
-portable). 
-
-For such memory, you can do things like:
-
- - reading::
-
-	/*
-	 * read first 32 bits from ISA memory at 0xC0000, aka
-	 * C000:0000 in DOS terms
-	 */
-	unsigned int signature = isa_readl(0xC0000);
-
- - remapping and writing::
-
-	/*
-	 * remap framebuffer PCI memory area at 0xFC000000,
-	 * size 1MB, so that we can access it: We can directly
-	 * access only the 640k-1MB area, so anything else
-	 * has to be remapped.
-	 */
-	void __iomem *baseptr = ioremap(0xFC000000, 1024*1024);
-
-	/* write a 'A' to the offset 10 of the area */
-	writeb('A',baseptr+10);
-
-	/* unmap when we unload the driver */
-	iounmap(baseptr);
-
- - copying and clearing::
-
-	/* get the 6-byte Ethernet address at ISA address E000:0040 */
-	memcpy_fromio(kernel_buffer, 0xE0040, 6);
-	/* write a packet to the driver */
-	memcpy_toio(0xE1000, skb->data, skb->len);
-	/* clear the frame buffer */
-	memset_io(0xA0000, 0, 0x10000);
-
-OK, that just about covers the basics of accessing IO portably.  Questions?
-Comments? You may think that all the above is overly complex, but one day you
-might find yourself with a 500 MHz Alpha in front of you, and then you'll be
-happy that your driver works ;)
-
-Note that kernel versions 2.0.x (and earlier) mistakenly called the
-ioremap() function "vremap()".  ioremap() is the proper name, but I
-didn't think straight when I wrote it originally.  People who have to
-support both can do something like::
- 
-	/* support old naming silliness */
-	#if LINUX_VERSION_CODE < 0x020100
-	#define ioremap vremap
-	#define iounmap vfree                                                     
-	#endif
- 
-at the top of their source files, and then they can use the right names
-even on 2.0.x systems. 
-
-And the above sounds worse than it really is.  Most real drivers really
-don't do all that complex things (or rather: the complexity is not so
-much in the actual IO accesses as in error handling and timeouts etc). 
-It's generally not hard to fix drivers, and in many cases the code
-actually looks better afterwards::
-
-	unsigned long signature = *(unsigned int *) 0xC0000;
-		vs
-	unsigned long signature = readl(0xC0000);
-
-I think the second version actually is more readable, no?
diff --git a/Documentation/core-api/dma-api-howto.rst b/Documentation/core-api/dma-api-howto.rst
index 358d495456d1..828846804e25 100644
--- a/Documentation/core-api/dma-api-howto.rst
+++ b/Documentation/core-api/dma-api-howto.rst
@@ -707,20 +707,6 @@ to use the dma_sync_*() interfaces::
 		}
 	}
 
-Drivers converted fully to this interface should not use virt_to_bus() any
-longer, nor should they use bus_to_virt(). Some drivers have to be changed a
-little bit, because there is no longer an equivalent to bus_to_virt() in the
-dynamic DMA mapping scheme - you have to always store the DMA addresses
-returned by the dma_alloc_coherent(), dma_pool_alloc(), and dma_map_single()
-calls (dma_map_sg() stores them in the scatterlist itself if the platform
-supports dynamic DMA mapping in hardware) in your driver structures and/or
-in the card registers.
-
-All drivers should be using these interfaces with no exceptions.  It
-is planned to completely remove virt_to_bus() and bus_to_virt() as
-they are entirely deprecated.  Some ports already do not provide these
-as it is impossible to correctly support them.
-
 Handling Errors
 ===============
 
diff --git a/Documentation/core-api/index.rst b/Documentation/core-api/index.rst
index dedd4d853329..726065a3095e 100644
--- a/Documentation/core-api/index.rst
+++ b/Documentation/core-api/index.rst
@@ -41,7 +41,6 @@ Library functionality that is used throughout the kernel.
    rbtree
    generic-radix-tree
    packing
-   bus-virt-phys-mapping
    this_cpu_ops
    timekeeping
    errseq