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sdram: reject read delay wrap arounds

This commit is contained in:
Robert Jördens 2018-03-20 07:27:51 +08:00 committed by Robert Jordens
parent 65379b1f7a
commit 276b0c7f06
1 changed files with 11 additions and 2 deletions
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13
artiq/firmware/libboard/sdram.rs
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@ -321,6 +321,8 @@ mod ddr {
let mut min_delay = 0; let mut min_delay = 0;
let mut have_min_delay = false; let mut have_min_delay = false;
let mut max_delay = 0; let mut max_delay = 0;
let mut have_max_delay = false;
let mut have_invalid = 0;
ddrphy::rdly_dq_rst_write(1); ddrphy::rdly_dq_rst_write(1);
@ -328,7 +330,7 @@ mod ddr {
let mut valid = true; let mut valid = true;
for _ in 0..256 { for _ in 0..256 {
sdram_phy::command_prd(DFII_COMMAND_CAS|DFII_COMMAND_CS| sdram_phy::command_prd(DFII_COMMAND_CAS|DFII_COMMAND_CS|
DFII_COMMAND_RDDATA); DFII_COMMAND_RDDATA);
spin_cycles(15); spin_cycles(15);
for p in 0..DFII_NPHASES { for p in 0..DFII_NPHASES {
@ -347,7 +349,14 @@ mod ddr {
min_delay = delay; min_delay = delay;
have_min_delay = true; have_min_delay = true;
} }
max_delay = delay; if !have_max_delay {
max_delay = delay;
}
} else if have_min_delay {
have_invalid += 1;
if have_invalid >= 10 {
have_max_delay = true;
}
} }
ddrphy::rdly_dq_inc_write(1); ddrphy::rdly_dq_inc_write(1);
} }