On Fri, Oct 14 2022 at 10:10, Nipun Gupta wrote:

Since CDX devices are not linked to of node they need a
separate MSI domain for handling device ID to be provided to
the GIC ITS domain.

This also introduces APIs to alloc and free IRQs for CDX domain.

This is not really much of an explanation.

+#include "cdx.h"
+
+#define REQ_ID_SHIFT	10
+
+/*
+ * Convert an msi_desc to a globaly unique identifier (per-device
+ * reqid + msi_desc position in the msi_list).
+ */
+static irq_hw_number_t cdx_domain_calc_hwirq(struct cdx_device *dev,
+					     struct msi_desc *desc)
+{
+	return (dev->req_id << REQ_ID_SHIFT) | desc->msi_index;
+}
+
+static void cdx_msi_set_desc(msi_alloc_info_t *arg,
+			     struct msi_desc *desc)
+{
+	arg->desc = desc;
+	arg->hwirq = cdx_domain_calc_hwirq(to_cdx_device(desc->dev), desc);
+}
+
+static void cdx_msi_write_msg(struct irq_data *irq_data,
+			      struct msi_msg *msg)
+{
+	struct msi_desc *msi_desc = irq_data_get_msi_desc(irq_data);
+	struct cdx_device *cdx_dev = to_cdx_device(msi_desc->dev);
+	struct cdx_controller_t *cdx = cdx_dev->cdx;
+	uint64_t addr;
+	int ret;
+
+	addr = ((uint64_t)(msi_desc->msg.address_hi) << 32) |
+	       msi_desc->msg.address_lo;
+
+	ret = cdx->ops.write_msi(cdx, cdx_dev->bus_num, cdx_dev->dev_num,
+				 msi_desc->msi_index, msi_desc->msg.data,
+				 addr);
+	if (ret)
+		dev_err(&cdx_dev->dev, "Write MSI failed to CDX controller\n");
+}

So this is yet another variant of platform-MSI which is about to be
kicked from the planet.

Please check:

     https://lore.kernel.org/r/20221111131813.914374272@linutronix.de
     https://lore.kernel.org/r/20221111133158.196269823@linutronix.de (local)

and the ARM/GIC conversion in:

     https://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git/log/?h=devmsi-arm

The latter is WIP, but functional.

I'm sure you replace your yet another magic MSI domain which only
provides a device specific MSI write function with the new
infrastructure trivially.

Thanks,

        tglx



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