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Kernel: Wait for NVMe controller to change enabled state

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We need to wait up to CAP.TO units of 500ms when changing CC.EN to
enable or disable the controller.
This commit is contained in:
Tom 2022-01-15 13:45:50 -07:00 • committed by Brian Gianforcaro
parent 8a879e205b
commit 0d65af5e0f
3 changed files with 61 additions and 15 deletions
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59
Kernel/Storage/NVMe/NVMeController.cpp
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@ -47,11 +47,14 @@ ErrorOr<void> NVMeController::initialize()
// Queues will individually map the doorbell register respectively
m_controller_regs = TRY(Memory::map_typed_writable<volatile ControllerRegister>(PhysicalAddress(m_bar)));
auto caps = m_controller_regs->cap;
m_ready_timeout = Time::from_milliseconds(CAP_TO(caps) * 500); // CAP.TO is in 500ms units
calculate_doorbell_stride();
TRY(create_admin_queue(irq));
VERIFY(m_admin_queue_ready == true);
VERIFY(IO_QUEUE_SIZE < MQES(m_controller_regs->cap));
VERIFY(IO_QUEUE_SIZE < MQES(caps));
dbgln_if(NVME_DEBUG, "NVMe: IO queue depth is: {}", IO_QUEUE_SIZE);
// Create an IO queue per core
@ -63,14 +66,37 @@ ErrorOr<void> NVMeController::initialize()
return {};
}
bool NVMeController::wait_for_ready(bool expected_ready_bit_value)
{
static constexpr size_t one_ms_io_delay = 1000;
auto wait_iterations = max(1, m_ready_timeout.to_milliseconds());
u32 expected_rdy = expected_ready_bit_value ? 1 : 0;
while (((m_controller_regs->csts >> CSTS_RDY_BIT) & 0x1) != expected_rdy) {
IO::delay(one_ms_io_delay);
if (--wait_iterations == 0) {
if (((m_controller_regs->csts >> CSTS_RDY_BIT) & 0x1) != expected_rdy) {
dbgln_if(NVME_DEBUG, "NVMEController: CSTS.RDY still not set to {} after {} ms", expected_rdy, m_ready_timeout.to_milliseconds());
return false;
}
break;
}
}
return true;
}
bool NVMeController::reset_controller()
{
volatile u32 cc, csts;
csts = m_controller_regs->csts;
if ((csts & (1 << CSTS_RDY_BIT)) != 0x1)
return false;
if ((m_controller_regs->cc & (1 << CC_EN_BIT)) != 0) {
// If the EN bit is already set, we need to wait
// until the RDY bit is 1, otherwise the behavior is undefined
if (!wait_for_ready(true))
return false;
}
auto cc = m_controller_regs->cc;
cc = m_controller_regs->cc;
cc = cc & ~(1 << CC_EN_BIT);
m_controller_regs->cc = cc;
@ -78,8 +104,8 @@ bool NVMeController::reset_controller()
IO::delay(10);
full_memory_barrier();
csts = m_controller_regs->csts;
if ((csts & (1 << CSTS_RDY_BIT)) != 0x0)
// Wait until the RDY bit is cleared
if (!wait_for_ready(false))
return false;
return true;
@ -87,12 +113,14 @@ bool NVMeController::reset_controller()
bool NVMeController::start_controller()
{
volatile u32 cc, csts;
csts = m_controller_regs->csts;
if ((csts & (1 << CSTS_RDY_BIT)) != 0x0)
return false;
if (!(m_controller_regs->cc & (1 << CC_EN_BIT))) {
// If the EN bit is not already set, we need to wait
// until the RDY bit is 0, otherwise the behavior is undefined
if (!wait_for_ready(false))
return false;
}
cc = m_controller_regs->cc;
auto cc = m_controller_regs->cc;
cc = cc | (1 << CC_EN_BIT);
cc = cc | (CQ_WIDTH << CC_IOCQES_BIT);
@ -102,8 +130,9 @@ bool NVMeController::start_controller()
IO::delay(10);
full_memory_barrier();
csts = m_controller_regs->csts;
if ((csts & (1 << CSTS_RDY_BIT)) != 0x1)
// Wait until the RDY bit is set
if (!wait_for_ready(true))
return false;
return true;