dmaengine: ste_dma40: physical channels number correction

DMAC_ICFG[0:2]=SCHNB only allows to count 'multiple of 4' physical
channels so it was ok with platforms having 8 channels but cannot be
used for next versions (with 10 or 14 channels).  This patch allows to
provide the number of physical channels for a DMA device via
platform_data, or still rely on SCHNB if platform_data announces 0
channel.

Signed-off-by: Gerald Baeza <gerald.baeza@stericsson.com>
Reviewed-by: Per Forlin <per.forlin@stericsson.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Vinod Koul <vinod.koul@intel.com>
Signed-off-by: Fabio Baltieri <fabio.baltieri@linaro.org>

drivers/dma/ste_dma40.c

@@ -3004,14 +3004,21 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
 	 * ? has revision 1
 	 * DB8500v1 has revision 2
 	 * DB8500v2 has revision 3
+	 * AP9540v1 has revision 4
+	 * DB8540v1 has revision 4
 	 */
 	rev = AMBA_REV_BITS(pid);
 
+	plat_data = pdev->dev.platform_data;
+
 	/* The number of physical channels on this HW */
-	num_phy_chans = 4 * (readl(virtbase + D40_DREG_ICFG) & 0x7) + 4;
+	if (plat_data->num_of_phy_chans)
+		num_phy_chans = plat_data->num_of_phy_chans;
+	else
+		num_phy_chans = 4 * (readl(virtbase + D40_DREG_ICFG) & 0x7) + 4;
 
-	dev_info(&pdev->dev, "hardware revision: %d @ 0x%x\n",
-		 rev, res->start);
+	dev_info(&pdev->dev, "hardware revision: %d @ 0x%x with %d physical channels\n",
+		 rev, res->start, num_phy_chans);
 
 	if (rev < 2) {
 		d40_err(&pdev->dev, "hardware revision: %d is not supported",
@@ -3019,8 +3026,6 @@ static struct d40_base * __init d40_hw_detect_init(struct platform_device *pdev)
 		goto failure;
 	}
 
-	plat_data = pdev->dev.platform_data;
-
 	/* Count the number of logical channels in use */
 	for (i = 0; i < plat_data->dev_len; i++)
 		if (plat_data->dev_rx[i] != 0)

include/linux/platform_data/dma-ste-dma40.h

@@ -147,6 +147,9 @@ struct stedma40_chan_cfg {
  * @memcpy_conf_log: default configuration of logical channel memcpy
  * @disabled_channels: A vector, ending with -1, that marks physical channels
  * that are for different reasons not available for the driver.
+ * @num_of_phy_chans: The number of physical channels implemented in HW.
+ * 0 means reading the number of channels from DMA HW but this is only valid
+ * for 'multiple of 4' channels, like 8.
  */
 struct stedma40_platform_data {
 	u32				 dev_len;
@@ -158,6 +161,7 @@ struct stedma40_platform_data {
 	struct stedma40_chan_cfg	*memcpy_conf_log;
 	int				 disabled_channels[STEDMA40_MAX_PHYS];
 	bool				 use_esram_lcla;
+	int				 num_of_phy_chans;
 };
 
 #ifdef CONFIG_STE_DMA40