On 03-07-18, 09:10, Timur Tabi wrote:

On 7/3/18 1:04 AM, Vinod Koul wrote:

quoted

Add support for probing on ACPI systems, with ACPI HID QCOM8160.

On ACPI systems, clocks are always enabled, the PRNG should
already be enabled, and the register region is read-only.
The driver only verifies that the hardware is already
enabled never tries to disable or configure it.

Signed-off-by: Timur Tabi<redacted>
[port to crypto API]
Signed-off-by: Vinod Koul<vkoul@kernel.org>

I've asked a colleague who still works at Qualcomm to test this code on
silicon.  It looks okay, but I just want to be sure.

quoted

+	/*
+	 * ACPI systems have v2 hardware. The clocks are always enabled,
+	 * the PRNG register space is read-only and the PRNG should
+	 * already be enabled.
+	 */
+	if (has_acpi_companion(&pdev->dev)) {
+		val = readl(rng->base + PRNG_CONFIG);
+		if (!(val & PRNG_CONFIG_HW_ENABLE)) {
+			dev_err(&pdev->dev, "device is not enabled\n");
+			return -ENODEV;
+		}

I'm having second thoughts about this PRNG_CONFIG_HW_ENABLE check.  The PRNG
on the QDF2400 is the same as the one on the 8996, so it should have the
same register interface.  Currently, the ACPI table points to a full PRNG
register block, but I'm beginning to believe that it should instead point to
a "reduced" block that doesn't have a PRNG_CONFIG register.

That was my doubt too. I will go ahead and make it skip this then...

-- 
~Vinod