[PATCH] caam: Fix CAAM error on startup

[Fabio Estevam]

From: Olaf Baehring <olaf.baehr...@draeger.com>

In rare cases U-Boot returns an error message when intantiating the RNG
of the CAAM device:
“SEC0:  RNG4 SH0 instantiation failed with error 0xffffffff”
This  means, that even when the CAAM device reports a finished
descriptor, none is found in the output ring.
This might be caused by a missing cache invalidation before
reading the memory of the output ring
This patch moves the cache invalidation of the output ring from start of
the job to immediately after the notification from hardware where the
output ring will be read.

Signed-off-by: Olaf Baehring <olaf.baehr...@draeger.com>
Signed-off-by: Fabio Estevam <feste...@gmail.com>
---
 drivers/crypto/fsl/jr.c | 25 ++++++++++++++-----------
 drivers/crypto/fsl/jr.h |  4 ----
 2 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/drivers/crypto/fsl/jr.c b/drivers/crypto/fsl/jr.c
index 8f7a821ebf3d..1d95d2bff278 100644
--- a/drivers/crypto/fsl/jr.c
+++ b/drivers/crypto/fsl/jr.c
@@ -217,13 +217,6 @@ static int jr_enqueue(uint32_t *desc_addr,
 
        jr->head = (head + 1) & (jr->size - 1);
 
-       /* Invalidate output ring */
-       start = (unsigned long)jr->output_ring &
-                                       ~(ARCH_DMA_MINALIGN - 1);
-       end = ALIGN((unsigned long)jr->output_ring + jr->op_size,
-                   ARCH_DMA_MINALIGN);
-       invalidate_dcache_range(start, end);
-
        sec_out32(&regs->irja, 1);
 
        return 0;
@@ -243,6 +236,7 @@ static int jr_dequeue(int sec_idx, struct caam_regs *caam)
 #else
        uint32_t *addr;
 #endif
+       unsigned long start, end;
 
        while (sec_in32(&regs->orsf) && CIRC_CNT(jr->head, jr->tail,
                                                 jr->size)) {
@@ -250,6 +244,11 @@ static int jr_dequeue(int sec_idx, struct caam_regs *caam)
                found = 0;
 
                caam_dma_addr_t op_desc;
+
+               /* Invalidate output ring */
+               start = (unsigned long)jr->output_ring & ~(ARCH_DMA_MINALIGN - 
1);
+               end = ALIGN((unsigned long)jr->output_ring + jr->op_size, 
ARCH_DMA_MINALIGN);
+               invalidate_dcache_range(start, end);
        #ifdef CONFIG_CAAM_64BIT
                /* Read the 64 bit Descriptor address from Output Ring.
                 * The 32 bit hign and low part of the address will
@@ -283,8 +282,13 @@ static int jr_dequeue(int sec_idx, struct caam_regs *caam)
                }
 
                /* Error condition if match not found */
-               if (!found)
+               if (!found) {
+                       int slots_full = sec_in32(&regs->orsf);
+
+                       jr->tail = (jr->tail + slots_full) & (jr->size - 1);
+                       sec_out32(&regs->orjr, slots_full);
                        return -1;
+               }
 
                jr->info[idx].op_done = 1;
                callback = (void *)jr->info[idx].callback;
@@ -296,14 +300,14 @@ static int jr_dequeue(int sec_idx, struct caam_regs *caam)
                 */
                if (idx == tail)
                        do {
+                               jr->info[tail].op_done = 0;
                                tail = (tail + 1) & (jr->size - 1);
                        } while (jr->info[tail].op_done);
 
                jr->tail = tail;
-               jr->read_idx = (jr->read_idx + 1) & (jr->size - 1);
+
 
                sec_out32(&regs->orjr, 1);
-               jr->info[idx].op_done = 0;
 
                callback(status, arg);
        }
@@ -378,7 +382,6 @@ static int jr_sw_cleanup(uint8_t sec_idx, struct caam_regs 
*caam)
 
        jr->head = 0;
        jr->tail = 0;
-       jr->read_idx = 0;
        jr->write_idx = 0;
        memset(jr->info, 0, sizeof(jr->info));
        memset(jr->input_ring, 0, jr->size * sizeof(caam_dma_addr_t));
diff --git a/drivers/crypto/fsl/jr.h b/drivers/crypto/fsl/jr.h
index b136cd8d05a9..8d5ca03e5015 100644
--- a/drivers/crypto/fsl/jr.h
+++ b/drivers/crypto/fsl/jr.h
@@ -83,10 +83,6 @@ struct jobring {
         * in-order job completion
         */
        int tail;
-       /* Read index of the output ring. It may not match with tail in case
-        * of out of order completetion
-        */
-       int read_idx;
        /* Write index to input ring. Would be always equal to head */
        int write_idx;
        /* Size of the rings. */
-- 
2.34.1