Re: [PATCH v5 01/10] i3c: Add core I3C infrastructure

From: vitor
Date: Thu Jun 28 2018 - 11:39:28 EST


Hi Boris,


On 22-06-2018 11:49, Boris Brezillon wrote:
+static int of_i3c_master_add_i3c_dev(struct i3c_master_controller *master,
+ struct device_node *node, u32 *reg)
+{
+ struct i3c_device_info info = { };
+ enum i3c_addr_slot_status addrstatus;
+ struct i3c_device *i3cdev;
+ u32 init_dyn_addr = 0;
+
+ if (reg[0]) {
+ if (reg[0] > I3C_MAX_ADDR)
+ return -EINVAL;
+
+ addrstatus = i3c_bus_get_addr_slot_status(master->bus, reg[0]);
+ if (addrstatus != I3C_ADDR_SLOT_FREE)
+ return -EINVAL;
+ }
+
+ info.static_addr = reg[0];
+
+ if (!of_property_read_u32(node, "assigned-address", &init_dyn_addr)) {
+ if (init_dyn_addr > I3C_MAX_ADDR)
+ return -EINVAL;
+
+ addrstatus = i3c_bus_get_addr_slot_status(master->bus,
+ init_dyn_addr);
+ if (addrstatus != I3C_ADDR_SLOT_FREE)
+ return -EINVAL;
+ }
+
+ info.pid = ((u64)reg[1] << 32) | reg[2];
+
+ if ((info.pid & GENMASK_ULL(63, 48)) ||
+ I3C_PID_RND_LOWER_32BITS(info.pid))
+ return -EINVAL;
+
+ i3cdev = i3c_master_alloc_i3c_dev(master, &info, &i3c_device_type);
+ if (IS_ERR(i3cdev))
+ return PTR_ERR(i3cdev);
+
+ i3cdev->init_dyn_addr = init_dyn_addr;
+ i3cdev->dev.of_node = node;
+ list_add_tail(&i3cdev->common.node, &master->bus->devs.i3c);
+
+ return 0;
+}
+

I'm writing the driver for the Synopsys master and but now I getting an issue.

I use the "slot" of the device to do all transfers, something like you use in DAA. I using the master_priv to save the "slot" per device but the problem is when I call the i3c_master_add_i3c_dev_locked() to retrieve the info I don't have it yet.

From my analysis this can be solve with:
ÂÂÂ - send PID, BCR and DCR when I call i3c_master_add_i3c_dev_locked() or similar function.
ÂÂÂ - Pre-allocate an i3c_device -> attach it (slot data goes to master_priv) -> retrieve info -> if there is already an i3c_device with same PID destroy the pre-allocated one.
ÂÂÂ - Replace the info.dyn_address with a structure with dyn_address and slot and use it in CCC structure.

This is something that will need to be supported for I3C HCI spec too. Do you have any suggestion?

Best regards,
Vitor Soares