[RFC PATCH v2 4/8] iommu/rockchip: take all DT clocks

[Jiaxing Hu <gahing@gahingwoo.com>]

rk_iommu only enabled a fixed {aclk,iface} pair.  On the RK3576 NPU the
MMU sits behind the CBUF/DSU gates, so writes to DTE_ADDR are silently
dropped until those clocks run too (reads work, writes need more clocks).
Use devm_clk_bulk_get_all() to take every clock the devicetree provides
instead of a fixed pair, so a platform can list the full set it needs.
Clocks stay optional for the older clock-less devicetrees.

Signed-off-by: Jiaxing Hu <gahing@gahingwoo.com>
---
 drivers/iommu/rockchip-iommu.c | 28 +++++++++-------------------
 1 file changed, 9 insertions(+), 19 deletions(-)

diff --git a/drivers/iommu/rockchip-iommu.c b/drivers/iommu/rockchip-iommu.c
index 0013cf196..62cd6b022 100644
--- a/drivers/iommu/rockchip-iommu.c
+++ b/drivers/iommu/rockchip-iommu.c
@@ -93,11 +93,6 @@ struct rk_iommu_domain {
 	struct iommu_domain domain;
 };
 
-/* list of clocks required by IOMMU */
-static const char * const rk_iommu_clocks[] = {
-	"aclk", "iface",
-};
-
 struct rk_iommu_ops {
 	phys_addr_t (*pt_address)(u32 dte);
 	u32 (*mk_dtentries)(dma_addr_t pt_dma);
@@ -1246,25 +1241,20 @@ static int rk_iommu_probe(struct platform_device *pdev)
 	iommu->reset_disabled = device_property_read_bool(dev,
 					"rockchip,disable-mmu-reset");
 
-	iommu->num_clocks = ARRAY_SIZE(rk_iommu_clocks);
-	iommu->clocks = devm_kcalloc(iommu->dev, iommu->num_clocks,
-				     sizeof(*iommu->clocks), GFP_KERNEL);
-	if (!iommu->clocks)
-		return -ENOMEM;
-
-	for (i = 0; i < iommu->num_clocks; ++i)
-		iommu->clocks[i].id = rk_iommu_clocks[i];
-
 	/*
-	 * iommu clocks should be present for all new devices and devicetrees
-	 * but there are older devicetrees without clocks out in the wild.
-	 * So clocks as optional for the time being.
+	 * Take every clock the devicetree provides.  Most IOMMU instances
+	 * need exactly "aclk" + "iface", but e.g. the RK3576 NPU IOMMUs sit
+	 * behind additional gates (CBUF/DSU) whose clocks must be running
+	 * for register writes to land.  Clocks stay optional because there
+	 * are older devicetrees without clocks out in the wild.
 	 */
-	err = devm_clk_bulk_get(iommu->dev, iommu->num_clocks, iommu->clocks);
+	err = devm_clk_bulk_get_all(iommu->dev, &iommu->clocks);
 	if (err == -ENOENT)
 		iommu->num_clocks = 0;
-	else if (err)
+	else if (err < 0)
 		return err;
+	else
+		iommu->num_clocks = err;
 
 	err = clk_bulk_prepare(iommu->num_clocks, iommu->clocks);
 	if (err)
-- 
2.43.0