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arch/arm/stm32h7: Add lazy FPU for STM32H7 ARMV7 single core chips #15876

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arch/arm/stm32h7: Add lazy FPU for STM32H7 ARMV7 single core chips #15876

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19 changes: 18 additions & 1 deletion arch/arm/include/armv7-m/irq.h
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Original file line number Diff line number Diff line change
Expand Up @@ -106,9 +106,17 @@
# define SW_FPU_REGS (0)
#endif

/* The total number of registers saved by software */
/* The total number of registers saved by software.
* If lazy FPU is enabled, save only integer registers. FPU registers are
* handled separately.
*/

#ifndef CONFIG_ARCH_LAZYFPU
#define SW_XCPT_REGS (SW_INT_REGS + SW_FPU_REGS)
#else
#define SW_XCPT_REGS (SW_INT_REGS)
#endif

#define SW_XCPT_SIZE (4 * SW_XCPT_REGS)

/* On entry into an IRQ, the hardware automatically saves the following
Expand Down Expand Up @@ -153,7 +161,16 @@
# define HW_FPU_REGS (0)
#endif

/* If lazy FPU is enabled, save only integer registers. FPU registers are
* handled separately.
*/

#ifndef CONFIG_ARCH_LAZYFPU
#define HW_XCPT_REGS (HW_INT_REGS + HW_FPU_REGS)
#else
#define HW_XCPT_REGS (HW_INT_REGS)
#endif

#define HW_XCPT_SIZE (4 * HW_XCPT_REGS)

#define XCPTCONTEXT_REGS (HW_XCPT_REGS + SW_XCPT_REGS)
Expand Down
30 changes: 30 additions & 0 deletions arch/arm/src/armv7-m/arm_fpuconfig.c
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Original file line number Diff line number Diff line change
Expand Up @@ -24,6 +24,8 @@
* Included Files
****************************************************************************/

#include <nuttx/config.h>

#include "nvic.h"
#include "arm_internal.h"

Expand Down Expand Up @@ -56,6 +58,7 @@
*
****************************************************************************/

#ifndef CONFIG_ARCH_LAZYFPU
void arm_fpuconfig(void)
{
uint32_t regval;
Expand Down Expand Up @@ -83,3 +86,30 @@ void arm_fpuconfig(void)
regval |= NVIC_CPACR_CP_FULL(10) | NVIC_CPACR_CP_FULL(11);
putreg32(regval, NVIC_CPACR);
}
#else
void arm_fpuconfig(void)
{
uint32_t regval;

/* Clear CONTROL.FPCA so that we do not get the extended context frame
* with the volatile FP registers stacked in the saved context.
*/

regval = getcontrol();
regval &= ~CONTROL_FPCA;
setcontrol(regval);

/* Enable lazy stacking (LSPEN) and automatic state preservation (ASPEN).
*/

regval = getreg32(NVIC_FPCCR);
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can we use one arm_fpuconfig but add #ifdef/#else/#endif into the code fragment?

regval |= (NVIC_FPCCR_ASPEN | NVIC_FPCCR_LSPEN);
putreg32(regval, NVIC_FPCCR);

/* Enable full access to CP10 and CP11 */

regval = getreg32(NVIC_CPACR);
regval |= NVIC_CPACR_CP_FULL(10) | NVIC_CPACR_CP_FULL(11);
putreg32(regval, NVIC_CPACR);
}
#endif
2 changes: 2 additions & 0 deletions arch/arm/src/stm32h7/Kconfig
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Expand Up @@ -382,6 +382,7 @@ config STM32H7_STM32H7X3XX
bool
default n
select ARCH_HAVE_FPU
select ARCH_HAVE_LAZYFPU
select ARCH_HAVE_DPFPU
select STM32H7_HAVE_LTDC
select STM32H7_HAVE_ETHERNET
Expand All @@ -396,6 +397,7 @@ config STM32H7_STM32H7B3XX
bool
default n
select ARCH_HAVE_FPU
select ARCH_HAVE_LAZYFPU
select ARCH_HAVE_DPFPU
select STM32H7_HAVE_ETHERNET
select STM32H7_HAVE_FMC
Expand Down
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