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47 lines
1.9 KiB
Markdown
47 lines
1.9 KiB
Markdown
### NVME SSD Power Control Manager
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#### Description
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The package mantains for SSD power control and related noification handle Deamon
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#### Design
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The service power supply design follow PCI Express Card Electromechanical Specification Revision 3.0 in Section 2.2
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nvme_gpio.service follow section 2.2.1 Initial power-Up to initinal and adjust related signal.
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nvme_powermanager.service follow section 2.2.2 power management states monitor PRESENT signal and update related signal.
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#### Process
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* Plugging
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1. U2_[SSD_index] PRSNT_N will be input low
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2. Set PWR_U2_[SSD_index]_EN to high
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3. Check PWRGD_U2_[SSD_index] is high
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4-1. If PWRGD_U2_[SSD_index] is high (PWR Good)
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- Wait 5ms
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- Enable PCI Clock by SMBus 9FGL0851
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- Wait 100ms
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- Set RST_BMC_U2 to high
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4-2. If PWRGD_U2_[SSD_index] is low (PWR Fail)
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- Set RST_BMC_U2_[SSD_index]_R_N to low
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- Wait 100ms
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- Disable PCI Clock by SMBus
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* Removing
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1. U2_[SSD_index] PRSNT_N will be input high
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2. Set RST_BMC_U2 to low
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3. Wait 100ms
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4. Disable PCI Clock by SMBus
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5. Wait 5ms
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6. PWR_U2_[SSD_index]_EN to low
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#### Test
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1. PRESENT detect SSD: The hardware design has been implemented.
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2. Initial SSD slot Power output: nvme_gpio service has tested on Module. It could sucess initial gpios and set correct power output.
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3. Detect PRESENT and change power setting: nvme_powermanager service has tested on Module. It could success detect SSD plugged or removal change power output.
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4. Improve initial power-up sequence: For matched hardware default initial power-up setting, the nvme_gpio service only set unplugged slot related signal.
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5. Improve service execute sequence: nvme_powermanager.service must wait for nvme_gpio.service ensure gpio export complete.
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