Re: [PATCH 09/12] m68k: use the coherent DMA code for coldfire without data cache

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hi Christoph,

On 16/10/23 15:47, Christoph Hellwig wrote:
Coldfire cores configured without a data cache are DMA coherent and
should thus simply use the simple coherent version of dma-direct.

Introduce a new COLDFIRE_COHERENT_DMA Kconfig symbol as a convenient
short hand for such configurations, and a M68K_NONCOHERENT_DMA symbol
for all cases where we need to build non-coherent DMA infrastructure
to simplify the Kconfig and code conditionals.

Not building the non-coherent DMA code slightly reduces the code
size for such configurations.

Numers for m5249evb_defconfig below:

   text	   data	    bss	    dec	    hex	filename
2896158	 401052	  65392	3362602	 334f2a	vmlinux.before
2895166	 400988	  65392	3361546	 334b0a	vmlinux.after

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
  arch/m68k/Kconfig         |  8 ++++----
  arch/m68k/Kconfig.cpu     | 12 ++++++++++++
  arch/m68k/kernel/Makefile |  2 +-
  arch/m68k/kernel/dma.c    |  2 +-
  4 files changed, 18 insertions(+), 6 deletions(-)

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 0430b8ba6b5cc6..6c585eae89f4dc 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -3,19 +3,19 @@ config M68K
  	bool
  	default y
  	select ARCH_32BIT_OFF_T
-	select ARCH_DMA_ALLOC if !MMU || COLDFIRE
+	select ARCH_DMA_ALLOC if M68K_NONCOHERENT_DMA && COLDFIRE
  	select ARCH_HAS_BINFMT_FLAT
  	select ARCH_HAS_CPU_FINALIZE_INIT if MMU
  	select ARCH_HAS_CURRENT_STACK_POINTER
-	select ARCH_HAS_DMA_PREP_COHERENT if HAS_DMA && MMU && !COLDFIRE
-	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if HAS_DMA
+	select ARCH_HAS_DMA_PREP_COHERENT if M68K_NONCOHERENT_DMA && !COLDFIRE
+	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if M68K_NONCOHERENT_DMA
  	select ARCH_HAVE_NMI_SAFE_CMPXCHG if RMW_INSNS
  	select ARCH_MIGHT_HAVE_PC_PARPORT if ISA
  	select ARCH_NO_PREEMPT if !COLDFIRE
  	select ARCH_USE_MEMTEST if MMU_MOTOROLA
  	select ARCH_WANT_IPC_PARSE_VERSION
  	select BINFMT_FLAT_ARGVP_ENVP_ON_STACK
-	select DMA_DIRECT_REMAP if HAS_DMA && MMU && !COLDFIRE
+	select DMA_DIRECT_REMAP if M68K_NONCOHERENT_DMA && !COLDFIRE
  	select GENERIC_ATOMIC64
  	select GENERIC_CPU_DEVICES
  	select GENERIC_IOMAP
diff --git a/arch/m68k/Kconfig.cpu b/arch/m68k/Kconfig.cpu
index b826e9c677b2ae..e8905d38c714c4 100644
--- a/arch/m68k/Kconfig.cpu
+++ b/arch/m68k/Kconfig.cpu
@@ -535,3 +535,15 @@ config CACHE_COPYBACK
  	  The ColdFire CPU cache is set into Copy-back mode.
  endchoice
  endif # HAVE_CACHE_CB
+
+# Coldfire cores that do not have a data cache configured can do coherent DMA.
+config COLDFIRE_COHERENT_DMA
+	bool
+	default y
+	depends on COLDFIRE
+	depends on !HAVE_CACHE_CB && !CONFIG_CACHE_D && !CONFIG_CACHE_BOTH
                                      ^^^^^^             ^^^^^^

This needs to be "depends on !HAVE_CACHE_CB && !CACHE_D && !CACHE_BOTH".

Regards
Greg


+
+config M68K_NONCOHERENT_DMA
+	bool
+	default y
+	depends on HAS_DMA && !COLDFIRE_COHERENT_DMA
diff --git a/arch/m68k/kernel/Makefile b/arch/m68k/kernel/Makefile
index af015447dfb4c1..01fb69a5095f43 100644
--- a/arch/m68k/kernel/Makefile
+++ b/arch/m68k/kernel/Makefile
@@ -23,7 +23,7 @@ obj-$(CONFIG_MMU_MOTOROLA) += ints.o vectors.o
  obj-$(CONFIG_MMU_SUN3) += ints.o vectors.o
  obj-$(CONFIG_PCI) += pcibios.o
-obj-$(CONFIG_HAS_DMA) += dma.o
+obj-$(CONFIG_M68K_NONCOHERENT_DMA) += dma.o
obj-$(CONFIG_KEXEC) += machine_kexec.o relocate_kernel.o
  obj-$(CONFIG_BOOTINFO_PROC)	+= bootinfo_proc.o
diff --git a/arch/m68k/kernel/dma.c b/arch/m68k/kernel/dma.c
index 2e192a5df949bb..f83870cfa79b37 100644
--- a/arch/m68k/kernel/dma.c
+++ b/arch/m68k/kernel/dma.c
@@ -17,7 +17,7 @@
#include <asm/cacheflush.h> -#if defined(CONFIG_MMU) && !defined(CONFIG_COLDFIRE)
+#ifndef CONFIG_COLDFIRE
  void arch_dma_prep_coherent(struct page *page, size_t size)
  {
  	cache_push(page_to_phys(page), size);



[Index of Archives]     [Linux Samsung SOC]     [Linux Wireless]     [Linux Kernel]     [ATH6KL]     [Linux Bluetooth]     [Linux Netdev]     [Kernel Newbies]     [IDE]     [Security]     [Git]     [Netfilter]     [Bugtraq]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Linux ATA RAID]     [Samba]     [Device Mapper]

  Powered by Linux