a1c5a06224
Some ARM CPUs have bitbanded IO, a memory region that allows convenient bit access via 32-bit memory loads/stores. This eliminates the need for read-modify-update instruction sequences. This patch makes this optional feature an ARMv7MState qdev property, allowing boards to choose whether they want bitbanding or not. Status of boards: * iotkit (Cortex M33), no bitband * mps2 (Cortex M3), bitband * msf2 (Cortex M3), bitband * stellaris (Cortex M3), bitband * stm32f205 (Cortex M3), bitband As a side-effect of this patch, Peter Maydell noted that the Ethernet controller on mps2 board is now accessible. Previously they were hidden by the bitband region (which does not exist on the real board). Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Message-id: 20180814162739.11814-2-stefanha@redhat.com Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
71 lines
2 KiB
C
71 lines
2 KiB
C
/*
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* ARMv7M CPU object
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*
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* Copyright (c) 2017 Linaro Ltd
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* Written by Peter Maydell <peter.maydell@linaro.org>
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*
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* This code is licensed under the GPL version 2 or later.
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*/
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#ifndef HW_ARM_ARMV7M_H
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#define HW_ARM_ARMV7M_H
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#include "hw/sysbus.h"
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#include "hw/intc/armv7m_nvic.h"
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#include "target/arm/idau.h"
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#define TYPE_BITBAND "ARM,bitband-memory"
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#define BITBAND(obj) OBJECT_CHECK(BitBandState, (obj), TYPE_BITBAND)
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typedef struct {
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/*< private >*/
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SysBusDevice parent_obj;
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/*< public >*/
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AddressSpace source_as;
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MemoryRegion iomem;
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uint32_t base;
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MemoryRegion *source_memory;
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} BitBandState;
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#define TYPE_ARMV7M "armv7m"
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#define ARMV7M(obj) OBJECT_CHECK(ARMv7MState, (obj), TYPE_ARMV7M)
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#define ARMV7M_NUM_BITBANDS 2
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/* ARMv7M container object.
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* + Unnamed GPIO input lines: external IRQ lines for the NVIC
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* + Named GPIO output SYSRESETREQ: signalled for guest AIRCR.SYSRESETREQ
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* + Property "cpu-type": CPU type to instantiate
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* + Property "num-irq": number of external IRQ lines
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* + Property "memory": MemoryRegion defining the physical address space
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* that CPU accesses see. (The NVIC, bitbanding and other CPU-internal
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* devices will be automatically layered on top of this view.)
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* + Property "idau": IDAU interface (forwarded to CPU object)
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* + Property "init-svtor": secure VTOR reset value (forwarded to CPU object)
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* + Property "enable-bitband": expose bitbanded IO
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*/
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typedef struct ARMv7MState {
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/*< private >*/
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SysBusDevice parent_obj;
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/*< public >*/
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NVICState nvic;
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BitBandState bitband[ARMV7M_NUM_BITBANDS];
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ARMCPU *cpu;
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/* MemoryRegion we pass to the CPU, with our devices layered on
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* top of the ones the board provides in board_memory.
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*/
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MemoryRegion container;
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/* Properties */
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char *cpu_type;
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/* MemoryRegion the board provides to us (with its devices, RAM, etc) */
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MemoryRegion *board_memory;
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Object *idau;
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uint32_t init_svtor;
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bool enable_bitband;
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} ARMv7MState;
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#endif
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