RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-05-31 07:48:11 +00:00
Code Issues Activity Actions

Kernel: Clear previous value before setting new clock divisor

Browse source 
Otherwise it would just get OR'ed together with the previous value,
leading to a slower than expected operation.
This commit is contained in:
Daniel Bertalan 2023-06-24 09:34:45 +02:00 • committed by Jelle Raaijmakers
parent 6185a19618
commit 73228fc742
1 changed files with 2 additions and 1 deletions
Download patch file Download diff file Expand all files Collapse all files

3
Kernel/Devices/Storage/SD/SDHostController.cpp
View file

@ -44,6 +44,7 @@ constexpr u32 dma_select_adma2_64 = 0b11 << 3;
constexpr u32 internal_clock_enable = 1 << 0;
constexpr u32 internal_clock_stable = 1 << 1;
constexpr u32 sd_clock_enable = 1 << 2;
constexpr u32 sd_clock_divisor_mask = 0x0000ffc0;
// In sub-register "Software Reset"
constexpr u32 software_reset_for_all = 0x01000000;
@ -446,7 +447,7 @@ ErrorOr<void> SDHostController::sd_clock_supply(u32 frequency)
const u32 two_upper_bits_of_sdclk_frequency_select = (divisor >> 8 & 0x3) << 6;
sdclk_frequency_select |= two_upper_bits_of_sdclk_frequency_select;
}
m_registers->host_configuration_1 = m_registers->host_configuration_1 | internal_clock_enable | sdclk_frequency_select;
m_registers->host_configuration_1 = (m_registers->host_configuration_1 & ~sd_clock_divisor_mask) | internal_clock_enable | sdclk_frequency_select;
// 3. Check Internal Clock Stable in the Clock Control register until it is 1
if (!retry_with_timeout([&] { return m_registers->host_configuration_1 & internal_clock_stable; })) {