Altera Cyclone V Device Handbook page 745

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2013.12.30
Alternative Boot Operation for eMMC Card Devices
The following figure illustrates the sequence of steps required to perform the alternative boot operation for
eMMC card devices. The detailed steps are described following the flow chart.
Figure 11-15: Flow for eMMC Alternative Boot Operation
1. The software driver checks:
• If the eMMC card device supports alternative boot operation (the BOOT_INFO bit is set to 1 in the
eMMC card).
• The BOOT_SIZE_MULT and BOOT_BUS_WIDTH values in the card device to use during the boot
process.
2. The software sets the following bits:
• Sets masks for interrupts by resetting the appropriate bits to 0 in the intmask register.
• Sets the int_enable bit of the ctrl register to 1. Other bits in the ctrl register must be set to
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0.
Note:
3. If the software driver needs to use the internal DMA controller to transfer the boot data received, it must
perform the following actions:
SD/MMC Controller
Send Feedback
expect_boot_ack = 1
Step 13
No Start Start Pattern & No
Pattern Boot Data Received
Step 14.a Step 14.b
Successfully
Received Boot
Data (14.d)
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Altera recommends writing 0xFFFFFFFF to the rintsts register and idsts register to
clear any pending interrupts before setting the int_enable bit. For internal DMA controller
mode, the software driver needs to unmask all the relevant fields in the idinten register.
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Alternative Boot Operation for eMMC Card Devices
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Start
Step 1
Step 2 to Step 12
Step 15
Start Pattern &
Boot Data Received
Step 14.e Step 16.a
NAC Timeout
Step 14.h
Stop
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expect_boot_ack = 0
No Boot Data Boot Data
Received Received
Step 16.b
Successfully
Received Boot
Data (16.d)
11-67
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Altera Corporation