[PATCH v2 2/3] staging: ccree: handle limiting of DMA masks

[Gilad Ben-Yossef]

Properly handle limiting of DMA masks based on device and bus
capabilities.

Signed-off-by: Gilad Ben-Yossef <gi...@benyossef.com>
---
 drivers/staging/ccree/ssi_driver.c | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/drivers/staging/ccree/ssi_driver.c 
b/drivers/staging/ccree/ssi_driver.c
index 5f03c25..1d4c7bb 100644
--- a/drivers/staging/ccree/ssi_driver.c
+++ b/drivers/staging/ccree/ssi_driver.c
@@ -208,6 +208,7 @@ static int init_cc_resources(struct platform_device 
*plat_dev)
        struct device *dev = &plat_dev->dev;
        struct device_node *np = dev->of_node;
        u32 signature_val;
+       dma_addr_t dma_mask;
        int rc = 0;
 
        new_drvdata = devm_kzalloc(dev, sizeof(*new_drvdata), GFP_KERNEL);
@@ -256,15 +257,29 @@ static int init_cc_resources(struct platform_device 
*plat_dev)
        }
        dev_dbg(dev, "Registered to IRQ: %d\n", new_drvdata->irq);
 
+       if (!plat_dev->dev.dma_mask)
+               plat_dev->dev.dma_mask = &plat_dev->dev.coherent_dma_mask;
+
+       dma_mask = (dma_addr_t)(DMA_BIT_MASK(DMA_BIT_MASK_LEN));
+       while (dma_mask > 0x7fffffffUL) {
+               if (dma_supported(&plat_dev->dev, dma_mask)) {
+                       rc = dma_set_coherent_mask(&plat_dev->dev, dma_mask);
+                       if (!rc)
+                               break;
+               }
+               dma_mask >>= 1;
+       }
+
+       if (rc) {
+               dev_err(dev, "Error: failed in dma_set_mask, mask=%par\n",
+                       &dma_mask);
+               goto post_drvdata_err;
+       }
+
        rc = cc_clk_on(new_drvdata);
        if (rc)
                goto post_drvdata_err;
 
-       if (!dev->dma_mask)
-               dev->dma_mask = &dev->coherent_dma_mask;
-
-       if (!dev->coherent_dma_mask)
-               dev->coherent_dma_mask = DMA_BIT_MASK(DMA_BIT_MASK_LEN);
 
        /* Verify correct mapping */
        signature_val = CC_HAL_READ_REGISTER(CC_REG_OFFSET(HOST_RGF, 
HOST_SIGNATURE));
-- 
2.7.4