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Diffstat (limited to 'Documentation/arm/tcm.rst')
| -rw-r--r-- | Documentation/arm/tcm.rst | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/Documentation/arm/tcm.rst b/Documentation/arm/tcm.rst index effd9c7bc968..1dc6c39220f9 100644 --- a/Documentation/arm/tcm.rst +++ b/Documentation/arm/tcm.rst @@ -4,18 +4,18 @@ ARM TCM (Tightly-Coupled Memory) handling in Linux Written by Linus Walleij <linus.walleij@stericsson.com> -Some ARM SoC:s have a so-called TCM (Tightly-Coupled Memory). +Some ARM SoCs have a so-called TCM (Tightly-Coupled Memory). This is usually just a few (4-64) KiB of RAM inside the ARM processor. -Due to being embedded inside the CPU The TCM has a +Due to being embedded inside the CPU, the TCM has a Harvard-architecture, so there is an ITCM (instruction TCM) and a DTCM (data TCM). The DTCM can not contain any instructions, but the ITCM can actually contain data. The size of DTCM or ITCM is minimum 4KiB so the typical minimum configuration is 4KiB ITCM and 4KiB DTCM. -ARM CPU:s have special registers to read out status, physical +ARM CPUs have special registers to read out status, physical location and size of TCM memories. arch/arm/include/asm/cputype.h defines a CPUID_TCM register that you can read out from the system control coprocessor. Documentation from ARM can be found @@ -34,7 +34,7 @@ CPU so it is usually wise not to overlap any physical RAM with the TCM. The TCM memory can then be remapped to another address again using -the MMU, but notice that the TCM if often used in situations where +the MMU, but notice that the TCM is often used in situations where the MMU is turned off. To avoid confusion the current Linux implementation will map the TCM 1 to 1 from physical to virtual memory in the location specified by the kernel. Currently Linux |