[PATCH v3 3/3] mailbox: zynqmp: Enable Bufferless IPI usage on Versal-based SOC's

Ben Levinsky
2024-04-10T17:08:35Z

On Xilinx-AMD Versal and Versal-NET, there exist both
inter-processor-interrupts with corresponding message buffers and without
such buffers.

Add a routine that, if the corresponding DT compatible
string "xlnx,versal-ipi-mailbox" is used then a Versal-based SOC
can use a mailbox Device Tree entry where both host and remote
can use either of the buffered or bufferless interrupts.

Signed-off-by: Ben Levinsky <ben.levinsky@amd.com>
---
drivers/mailbox/zynqmp-ipi-mailbox.c | 129 +++++++++++++++++++++++++--
1 file changed, 122 insertions(+), 7 deletions(-)

diff --git a/drivers/mailbox/zynqmp-ipi-mailbox.c b/drivers/mailbox/zynqmp-ipi-mailbox.c
index 56ba7135db54..1cb553cced90 100644
--- a/drivers/mailbox/zynqmp-ipi-mailbox.c
+++ b/drivers/mailbox/zynqmp-ipi-mailbox.c
@@ -52,6 +52,13 @@
#define IPI_MB_CHNL_TX 0 /* IPI mailbox TX channel */
#define IPI_MB_CHNL_RX 1 /* IPI mailbox RX channel */

+/* IPI Message Buffer Information */
+#define RESP_OFFSET 0x20U
+#define DEST_OFFSET 0x40U
+#define IPI_BUF_SIZE 0x20U
+#define DST_BIT_POS 9U
+#define SRC_BITMASK GENMASK(11, 8)
+
/**
* struct zynqmp_ipi_mchan - Description of a Xilinx ZynqMP IPI mailbox channel
* @is_opened: indicate if the IPI channel is opened
@@ -169,9 +176,11 @@ static irqreturn_t zynqmp_ipi_interrupt(int irq, void *data)
if (ret > 0 && ret & IPI_MB_STATUS_RECV_PENDING) {
if (mchan->is_opened) {
msg = mchan->rx_buf;
- msg->len = mchan->req_buf_size;
- memcpy_fromio(msg->data, mchan->req_buf,
- msg->len);
+ if (msg) {
+ msg->len = mchan->req_buf_size;
+ memcpy_fromio(msg->data, mchan->req_buf,
+ msg->len);
+ }
mbox_chan_received_data(chan, (void *)msg);
status = IRQ_HANDLED;
}
@@ -281,26 +290,26 @@ static int zynqmp_ipi_send_data(struct mbox_chan *chan, void *data)

if (mchan->chan_type == IPI_MB_CHNL_TX) {
/* Send request message */
- if (msg && msg->len > mchan->req_buf_size) {
+ if (msg && msg->len > mchan->req_buf_size && mchan->req_buf) {
dev_err(dev, "channel %d message length %u > max %lu\n",
mchan->chan_type, (unsigned int)msg->len,
mchan->req_buf_size);
return -EINVAL;
}
- if (msg && msg->len)
+ if (msg && msg->len && mchan->req_buf)
memcpy_toio(mchan->req_buf, msg->data, msg->len);
/* Kick IPI mailbox to send message */
arg0 = SMC_IPI_MAILBOX_NOTIFY;
zynqmp_ipi_fw_call(ipi_mbox, arg0, 0, &res);
} else {
/* Send response message */
- if (msg && msg->len > mchan->resp_buf_size) {
+ if (msg && msg->len > mchan->resp_buf_size && mchan->resp_buf) {
dev_err(dev, "channel %d message length %u > max %lu\n",
mchan->chan_type, (unsigned int)msg->len,
mchan->resp_buf_size);
return -EINVAL;
}
- if (msg && msg->len)
+ if (msg && msg->len && mchan->resp_buf)
memcpy_toio(mchan->resp_buf, msg->data, msg->len);
arg0 = SMC_IPI_MAILBOX_ACK;
zynqmp_ipi_fw_call(ipi_mbox, arg0, IPI_SMC_ACK_EIRQ_MASK,
@@ -636,6 +645,109 @@ static int zynqmp_ipi_setup(struct zynqmp_ipi_mbox *ipi_mbox,
return 0;
}

+/**
+ * versal_ipi_setup - Set up IPIs to support mixed usage of
+ * Buffered and Bufferless IPIs.
+ *
+ * @ipi_mbox: pointer to IPI mailbox private data structure
+ * @node: IPI mailbox device node
+ *
+ * Return: 0 for success, negative value for failure
+ */
+static int versal_ipi_setup(struct zynqmp_ipi_mbox *ipi_mbox,
+ struct device_node *node)
+{
+ struct zynqmp_ipi_mchan *tx_mchan, *rx_mchan;
+ struct resource host_res, remote_res;
+ struct device_node *parent_node;
+ int host_idx, remote_idx;
+ struct device *mdev;
+
+ tx_mchan = &ipi_mbox->mchans[IPI_MB_CHNL_TX];
+ rx_mchan = &ipi_mbox->mchans[IPI_MB_CHNL_RX];
+ parent_node = of_get_parent(node);
+ mdev = &ipi_mbox->dev;
+
+ host_idx = zynqmp_ipi_mbox_get_buf_res(parent_node, "msg", &host_res);
+ remote_idx = zynqmp_ipi_mbox_get_buf_res(node, "msg", &remote_res);
+
+ /*
+ * Only set up buffers if both sides claim to have msg buffers.
+ * This is because each buffered IPI's corresponding msg buffers
+ * are reserved for use by other buffered IPI's.
+ */
+ if (!host_idx && !remote_idx) {
+ u32 host_src, host_dst, remote_src, remote_dst;
+ u32 buff_sz;
+
+ buff_sz = resource_size(&host_res);
+
+ host_src = host_res.start & SRC_BITMASK;
+ remote_src = remote_res.start & SRC_BITMASK;
+
+ host_dst = (host_src >> DST_BIT_POS) * DEST_OFFSET;
+ remote_dst = (remote_src >> DST_BIT_POS) * DEST_OFFSET;
+
+ /* Validate that IPI IDs is within IPI Message buffer space. */
+ if (host_dst >= buff_sz || remote_dst >= buff_sz) {
+ dev_err(mdev,
+ "Invalid IPI Message buffer values: %x %x\n",
+ host_dst, remote_dst);
+ return -EINVAL;
+ }
+
+ tx_mchan->req_buf = devm_ioremap(mdev,
+ host_res.start | remote_dst,
+ IPI_BUF_SIZE);
+ if (!tx_mchan->req_buf) {
+ dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
+ return -ENOMEM;
+ }
+
+ tx_mchan->resp_buf = devm_ioremap(mdev,
+ (remote_res.start | host_dst) +
+ RESP_OFFSET, IPI_BUF_SIZE);
+ if (!tx_mchan->resp_buf) {
+ dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
+ return -ENOMEM;
+ }
+
+ rx_mchan->req_buf = devm_ioremap(mdev,
+ remote_res.start | host_dst,
+ IPI_BUF_SIZE);
+ if (!rx_mchan->req_buf) {
+ dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
+ return -ENOMEM;
+ }
+
+ rx_mchan->resp_buf = devm_ioremap(mdev,
+ (host_res.start | remote_dst) +
+ RESP_OFFSET, IPI_BUF_SIZE);
+ if (!rx_mchan->resp_buf) {
+ dev_err(mdev, "Unable to map IPI buffer I/O memory\n");
+ return -ENOMEM;
+ }
+
+ tx_mchan->resp_buf_size = IPI_BUF_SIZE;
+ tx_mchan->req_buf_size = IPI_BUF_SIZE;
+ tx_mchan->rx_buf = devm_kzalloc(mdev, IPI_BUF_SIZE +
+ sizeof(struct zynqmp_ipi_message),
+ GFP_KERNEL);
+ if (!tx_mchan->rx_buf)
+ return -ENOMEM;
+
+ rx_mchan->resp_buf_size = IPI_BUF_SIZE;
+ rx_mchan->req_buf_size = IPI_BUF_SIZE;
+ rx_mchan->rx_buf = devm_kzalloc(mdev, IPI_BUF_SIZE +
+ sizeof(struct zynqmp_ipi_message),
+ GFP_KERNEL);
+ if (!rx_mchan->rx_buf)
+ return -ENOMEM;
+ }
+
+ return 0;
+}
+
/**
* zynqmp_ipi_free_mboxes - Free IPI mailboxes devices
*
@@ -743,6 +855,9 @@ static const struct of_device_id zynqmp_ipi_of_match[] = {
{ .compatible = "xlnx,zynqmp-ipi-mailbox",
.data = &zynqmp_ipi_setup,
},
+ { .compatible = "xlnx,versal-ipi-mailbox",
+ .data = &versal_ipi_setup,
+ },
{},
};
MODULE_DEVICE_TABLE(of, zynqmp_ipi_of_match);
--
2.25.1