spi: fsi: Remove multiple sequenced ops for restricted chips

Updated restricted chips have trouble processing multiple sequenced
operations. So remove the capability to sequence multiple operations and
reduce the maximum transfer size to 8 bytes.

Signed-off-by: Eddie James <eajames@linux.ibm.com>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Link: https://lore.kernel.org/r/20210324220516.41192-1-eajames@linux.ibm.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-fsi.c b/drivers/spi/spi-fsi.c
index 3920cd3286d8a7d24c2430b9ec5e3c52f734c822..de359718e816f6d8dc70cce4367d7256f8d3a116 100644 (file)
--- a/drivers/spi/spi-fsi.c
+++ b/drivers/spi/spi-fsi.c
@@ -26,7 +26,7 @@
 #define SPI_FSI_BASE                   0x70000
 #define SPI_FSI_INIT_TIMEOUT_MS                1000
 #define SPI_FSI_MAX_XFR_SIZE           2048
-#define SPI_FSI_MAX_XFR_SIZE_RESTRICTED        32
+#define SPI_FSI_MAX_XFR_SIZE_RESTRICTED        8
 
 #define SPI_FSI_ERROR                  0x0
 #define SPI_FSI_COUNTER_CFG            0x1
@@ -265,14 +265,12 @@ static int fsi_spi_sequence_transfer(struct fsi_spi *ctx,
                                     struct fsi_spi_sequence *seq,
                                     struct spi_transfer *transfer)
 {
-       bool docfg = false;
        int loops;
        int idx;
        int rc;
        u8 val = 0;
        u8 len = min(transfer->len, 8U);
        u8 rem = transfer->len % len;
-       u64 cfg = 0ULL;
 
        loops = transfer->len / len;
 
@@ -292,28 +290,17 @@ static int fsi_spi_sequence_transfer(struct fsi_spi *ctx,
                return -EINVAL;
        }
 
-       if (ctx->restricted) {
-               const int eidx = rem ? 5 : 6;
-
-               while (loops > 1 && idx <= eidx) {
-                       idx = fsi_spi_sequence_add(seq, val);
-                       loops--;
-                       docfg = true;
-               }
-
-               if (loops > 1) {
-                       dev_warn(ctx->dev, "No sequencer slots; aborting.\n");
-                       return -EINVAL;
-               }
+       if (ctx->restricted && loops > 1) {
+               dev_warn(ctx->dev,
+                        "Transfer too large; no branches permitted.\n");
+               return -EINVAL;
        }
 
        if (loops > 1) {
+               u64 cfg = SPI_FSI_COUNTER_CFG_LOOPS(loops - 1);
+
                fsi_spi_sequence_add(seq, SPI_FSI_SEQUENCE_BRANCH(idx));
-               docfg = true;
-       }
 
-       if (docfg) {
-               cfg = SPI_FSI_COUNTER_CFG_LOOPS(loops - 1);
                if (transfer->rx_buf)
                        cfg |= SPI_FSI_COUNTER_CFG_N2_RX |
                                SPI_FSI_COUNTER_CFG_N2_TX |