ASoC: fsl-ssi: Add configuration helper functions

This patch adds a struct 'fsl_ssi_rxtx_reg_val' which holds register
values necessary to enable rx/tx. Based on those preset register values,
the added configuration functions will cleanly enable/disable different
parts of the SSI IP while supporting online/offline configuration.
Different operating modes can be setup directly as different register
values in fsl_ssi_reg_val.

These functions and structs will help to cleanup and simplify the
trigger function to support many different IP versions (online/offline
configuration) and different operating modes.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 122 insertions, 0 deletions

diff --git a/sound/soc/fsl/fsl_ssi.c b/sound/soc/fsl/fsl_ssi.c
index d0b9fe31f49a..a85268bb4507 100644
--- a/sound/soc/fsl/fsl_ssi.c
+++ b/sound/soc/fsl/fsl_ssi.c
@@ -131,6 +131,18 @@ enum fsl_ssi_type {
         FSL_SSI_MX51,
 };
 
+struct fsl_ssi_reg_val {
+        u32 sier;
+        u32 srcr;
+        u32 stcr;
+        u32 scr;
+};
+
+struct fsl_ssi_rxtx_reg_val {
+        struct fsl_ssi_reg_val rx;
+        struct fsl_ssi_reg_val tx;
+};
+
 /**
  * fsl_ssi_private: per-SSI private data
  *
@@ -169,6 +181,8 @@ struct fsl_ssi_private {
         struct imx_dma_data filter_data_tx;
         struct imx_dma_data filter_data_rx;
         struct imx_pcm_fiq_params fiq_params;
+        /* Register values for rx/tx configuration */
+        struct fsl_ssi_rxtx_reg_val rxtx_reg_val;
 
         struct {
                 unsigned int rfrc;
@@ -462,6 +476,114 @@ static void fsl_ssi_debugfs_remove(struct fsl_ssi_private *ssi_private)
 
 #endif /* IS_ENABLED(CONFIG_DEBUG_FS) */
 
+/*
+ * Enable/Disable all rx/tx config flags at once.
+ */
+static void fsl_ssi_rxtx_config(struct fsl_ssi_private *ssi_private,
+                bool enable)
+{
+        struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
+        struct fsl_ssi_rxtx_reg_val *vals = &ssi_private->rxtx_reg_val;
+
+        if (enable) {
+                write_ssi_mask(&ssi->sier, 0, vals->rx.sier | vals->tx.sier);
+                write_ssi_mask(&ssi->srcr, 0, vals->rx.srcr | vals->tx.srcr);
+                write_ssi_mask(&ssi->stcr, 0, vals->rx.stcr | vals->tx.stcr);
+        } else {
+                write_ssi_mask(&ssi->srcr, vals->rx.srcr | vals->tx.srcr, 0);
+                write_ssi_mask(&ssi->stcr, vals->rx.stcr | vals->tx.stcr, 0);
+                write_ssi_mask(&ssi->sier, vals->rx.sier | vals->tx.sier, 0);
+        }
+}
+
+/*
+ * Enable/Disable a ssi configuration. You have to pass either
+ * ssi_private->rxtx_reg_val.rx or tx as vals parameter.
+ */
+static void fsl_ssi_config(struct fsl_ssi_private *ssi_private, bool enable,
+                struct fsl_ssi_reg_val *vals)
+{
+        struct ccsr_ssi __iomem *ssi = ssi_private->ssi;
+        struct fsl_ssi_reg_val *avals;
+        u32 scr_val = read_ssi(&ssi->scr);
+        int nr_active_streams = !!(scr_val & CCSR_SSI_SCR_TE) +
+                                !!(scr_val & CCSR_SSI_SCR_RE);
+
+        /* Find the other direction values rx or tx which we do not want to
+         * modify */
+        if (&ssi_private->rxtx_reg_val.rx == vals)
+                avals = &ssi_private->rxtx_reg_val.tx;
+        else
+                avals = &ssi_private->rxtx_reg_val.rx;
+
+        /* If vals should be disabled, start with disabling the unit */
+        if (!enable) {
+                u32 scr = vals->scr & (vals->scr ^ avals->scr);
+                write_ssi_mask(&ssi->scr, scr, 0);
+        }
+
+        /*
+         * We are running on a SoC which does not support online SSI
+         * reconfiguration, so we have to enable all necessary flags at once
+         * even if we do not use them later (capture and playback configuration)
+         */
+        if (ssi_private->offline_config) {
+                if ((enable && !nr_active_streams) ||
+                                (!enable && nr_active_streams == 1))
+                        fsl_ssi_rxtx_config(ssi_private, enable);
+
+                goto config_done;
+        }
+
+        /*
+         * Configure single direction units while the SSI unit is running
+         * (online configuration)
+         */
+        if (enable) {
+                write_ssi_mask(&ssi->sier, 0, vals->sier);
+                write_ssi_mask(&ssi->srcr, 0, vals->srcr);
+                write_ssi_mask(&ssi->stcr, 0, vals->stcr);
+        } else {
+                u32 sier;
+                u32 srcr;
+                u32 stcr;
+
+                /*
+                 * Disabling the necessary flags for one of rx/tx while the
+                 * other stream is active is a little bit more difficult. We
+                 * have to disable only those flags that differ between both
+                 * streams (rx XOR tx) and that are set in the stream that is
+                 * disabled now. Otherwise we could alter flags of the other
+                 * stream
+                 */
+
+                /* These assignments are simply vals without bits set in avals*/
+                sier = vals->sier & (vals->sier ^ avals->sier);
+                srcr = vals->srcr & (vals->srcr ^ avals->srcr);
+                stcr = vals->stcr & (vals->stcr ^ avals->stcr);
+
+                write_ssi_mask(&ssi->srcr, srcr, 0);
+                write_ssi_mask(&ssi->stcr, stcr, 0);
+                write_ssi_mask(&ssi->sier, sier, 0);
+        }
+
+config_done:
+        /* Enabling of subunits is done after configuration */
+        if (enable)
+                write_ssi_mask(&ssi->scr, 0, vals->scr);
+}
+
+
+static void fsl_ssi_rx_config(struct fsl_ssi_private *ssi_private, bool enable)
+{
+        fsl_ssi_config(ssi_private, enable, &ssi_private->rxtx_reg_val.rx);
+}
+
+static void fsl_ssi_tx_config(struct fsl_ssi_private *ssi_private, bool enable)
+{
+        fsl_ssi_config(ssi_private, enable, &ssi_private->rxtx_reg_val.tx);
+}
+
 static void fsl_ssi_setup_ac97(struct fsl_ssi_private *ssi_private)
 {
         struct ccsr_ssi __iomem *ssi = ssi_private->ssi;