RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-20 13:45:06 +00:00
Code Issues Activity Actions

Kernel: Add High Speed support to the SDHC driver

Browse source 
This should not affect boot times on qemu, as that does not use
dynamic transfer delays in its adma code path.
On real hardware this could potentially double the data throughput,
decreasing load times.
This commit is contained in:
Hendiadyoin1 2023-04-08 15:01:19 +02:00 • committed by Sam Atkins
parent 857c9b4558
commit 863d0ac260
1 changed files with 9 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

11
Kernel/Storage/SD/SDHostController.cpp
View file

@ -32,9 +32,11 @@ static void delay(i64 nanoseconds)
}
constexpr u32 max_supported_sdsc_frequency = 25000000;
constexpr u32 max_supported_sdsc_frequency_high_speed = 50000000;
// In "m_registers->host_configuration_0"
// 2.2.11 Host Control 1 Register
constexpr u32 high_speed_enable = 1 << 2;
constexpr u32 dma_select_adma2_32 = 0b10 << 3;
constexpr u32 dma_select_adma2_64 = 0b11 << 3;
@ -221,8 +223,13 @@ ErrorOr<NonnullLockRefPtr<SDMemoryCard>> SDHostController::try_initialize_insert
u64 capacity = static_cast<u64>(block_count) * block_size;
u64 card_capacity_in_blocks = capacity / block_len;
// TODO: Do high speed initialisation, if supported
TRY(sd_clock_frequency_change(max_supported_sdsc_frequency));
if (m_registers->capabilities.high_speed) {
dbgln("SDHC: Enabling High Speed mode");
m_registers->host_configuration_0 = m_registers->host_configuration_0 | high_speed_enable;
TRY(sd_clock_frequency_change(max_supported_sdsc_frequency_high_speed));
} else {
TRY(sd_clock_frequency_change(max_supported_sdsc_frequency));
}
TRY(issue_command(SD::Commands::select_card, rca));
TRY(wait_for_response());