From: Gabriel Somlo <gsomlo@gmail.com>
Date: Fri, 27 Mar 2020 11:01:02 +0000 (-0400)
Subject: software/libbase/spisdcard: add delay to goidle loop
X-Git-Tag: 24jan2021_ls180~510^2~1
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=e9054ef65ad518cca6d792d9db767e19b3c60e3b;p=litex.git

software/libbase/spisdcard: add delay to goidle loop

In `spi_sdcard_goidle()`, insert a `busy_wait()` into the CMD55+ACMD41
loop to avoid exhausting the retry counter before the card has a chance
to be ready (required on the trellisboard, also tested OK on nexys4ddr).

Signed-off-by: Gabriel Somlo <gsomlo@gmail.com>
---

diff --git a/litex/soc/software/libbase/spisdcard.c b/litex/soc/software/libbase/spisdcard.c
index 0befe993..ab6cbe03 100644
--- a/litex/soc/software/libbase/spisdcard.c
+++ b/litex/soc/software/libbase/spisdcard.c
@@ -20,6 +20,7 @@
 #include <stdlib.h>
 #include <time.h>
 #include <string.h>
+#include <system.h>
 
 #define USE_SPISCARD_RECLOCKING
 
@@ -217,6 +218,7 @@ uint8_t spi_sdcard_goidle(void)
         spi_write_byte( 0xff ); spi_write_byte( 0x69 ); spi_write_byte( 0x40 ); spi_write_byte( 0x00 ); spi_write_byte( 0x00 ); spi_write_byte( 0x00 ); spi_write_byte( 0x00 );
         r = spi_read_rbyte();
         timeout--;
+        busy_wait(20);
     } while ((r != 0x00) && (timeout>0));
     if(r!=0x00) return FAILURE;