MMIO

Memory-mapped I/O register access. More...

Functions
static uint8_t	pbl_readb (uintptr_t addr)
	Read an 8-bit register.
static uint16_t	pbl_readw (uintptr_t addr)
	Read a 16-bit register.
static uint32_t	pbl_readl (uintptr_t addr)
	Read a 32-bit register.
static void	pbl_writeb (uint8_t val, uintptr_t addr)
	Write an 8-bit register.
static void	pbl_writew (uint16_t val, uintptr_t addr)
	Write a 16-bit register.
static void	pbl_writel (uint32_t val, uintptr_t addr)
	Write a 32-bit register.
static void	pbl_modifyb (uint8_t clear, uint8_t set, uintptr_t addr)
	Atomically clear and set bits of a shared 8-bit register.
static void	pbl_modifyw (uint16_t clear, uint16_t set, uintptr_t addr)
	Atomically clear and set bits of a shared 16-bit register.
static void	pbl_modifyl (uint32_t clear, uint32_t set, uintptr_t addr)
	Atomically clear and set bits of a shared 32-bit register.

Detailed Description

Memory-mapped I/O register access.

Each access is a single load or store of the given width. Accesses to the same device stay in program order, but are not ordered against normal memory: a driver that hands memory to a DMA engine orders them with pbl_wmb() and pbl_rmb():

buf[0] = cmd;
pbl_wmb();
pbl_writel(DMA_START, cfg->base + DMA_CTRL);
 
while ((pbl_readl(cfg->base + DMA_STATUS) & STATUS_DONE) == 0U) {
}
pbl_rmb();
reply = buf[1];

Registers shared between drivers, such as clock gates or system control bits, are updated with pbl_modifyl() and friends, which read, modify and write under pbl_irq_lock(). Registers owned by a single driver, and writes that are atomic in hardware (set/clear registers, write-1-to-clear flags), can use the plain accessors. Interrupts flagged PBL_IRQ_ZERO_LATENCY are not masked by the lock and must not touch shared registers.

Function Documentation

pbl_modifyb()

static void pbl_modifyb ( uint8_t  clear, uint8_t  set, uintptr_t  addr  )

static

Atomically clear and set bits of a shared 8-bit register.

Parameters

clear	Bits to clear.
set	Bits to set, applied after clear.
addr	Register address.

References pbl_irq_lock(), and pbl_irq_unlock().

pbl_modifyl()

static void pbl_modifyl ( uint32_t  clear, uint32_t  set, uintptr_t  addr  )

static

Atomically clear and set bits of a shared 32-bit register.

Parameters

clear	Bits to clear.
set	Bits to set, applied after clear.
addr	Register address, 4-byte aligned.

References pbl_irq_lock(), and pbl_irq_unlock().

pbl_modifyw()

static void pbl_modifyw ( uint16_t  clear, uint16_t  set, uintptr_t  addr  )

static

Atomically clear and set bits of a shared 16-bit register.

Parameters

clear	Bits to clear.
set	Bits to set, applied after clear.
addr	Register address, 2-byte aligned.

References pbl_irq_lock(), and pbl_irq_unlock().

pbl_readb()

static uint8_t pbl_readb ( uintptr_t  addr )

static

Read an 8-bit register.

Parameters

addr	Register address.

Returns

Register value.

pbl_readl()

static uint32_t pbl_readl ( uintptr_t  addr )

static

Read a 32-bit register.

Parameters

addr	Register address, 4-byte aligned.

Returns

Register value.

pbl_readw()

static uint16_t pbl_readw ( uintptr_t  addr )

static

Read a 16-bit register.

Parameters

addr	Register address, 2-byte aligned.

Returns

Register value.

pbl_writeb()

static void pbl_writeb ( uint8_t  val, uintptr_t  addr  )

static

Write an 8-bit register.

Parameters

val	Value to write.
addr	Register address.

pbl_writel()

static void pbl_writel ( uint32_t  val, uintptr_t  addr  )

static

Write a 32-bit register.

Parameters

val	Value to write.
addr	Register address, 4-byte aligned.

pbl_writew()

static void pbl_writew ( uint16_t  val, uintptr_t  addr  )

static

Write a 16-bit register.

Parameters

val	Value to write.
addr	Register address, 2-byte aligned.