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Commit 65676d4e authored by Arun Kumar Neelakantam's avatar Arun Kumar Neelakantam
Browse files

qrtr: Add FIFO based communication between VMs 



Add QRTR communication support between two virtual machines
by using shared FIFO and virtual IRQs.

Change-Id: I8fd2115a6ad5acd9a6dac2fa511860a8a68c16ee
Signed-off-by: default avatarArun Kumar Neelakantam <aneela@codeaurora.org>
parent 94399a5e

Documentation/devicetree/bindings/arm/msm/qrtr_fifo_xprt.txt

0 → 100644
+25 −0
Original line number Diff line number Diff line 
Qualcomm Technologies, Inc. IPC Router FIFO Transport



Required properties:

- compatible:	should be "qcom,ipcr_fifo_xprt"

- reg:		the irq register to raise an interrupt

- interrupts:	the receiving interrupt line

- qcom,ipc-shm:	Reference to shared memory phandle



Example:



	fifo_vipc_irq@176 {

		compatible = "qcom,ipcr-fifo-xprt";

		reg = <0x176>;

		interrupts = <0x0 0x142 0x1>;

		qcom,ipc-shm = <&ipc-shm>;

	};



	ipc-shm: shared-buffer@85af7000 {

		compatible = "qcom,hypervisor-shared-memory";

		phandle = <0x1e4>;

		reg = <0x0 0x85af7000 0x0 0x9000>;

		label = "ipc_shm";

		qcom,tx-is-first;

	};

net/qrtr/Kconfig

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@@ -34,4 +34,10 @@ config QRTR_USB 
	---help---

	  Say Y here to support USB based ipcrouter channels.



config QRTR_FIFO

	tristate "FIFO IPC Router channels"

	---help---

	Say Y here to support FIFO based ipcrouter channels. FIFO Transport

	Layer enables IPC Router communication between two virtual machines.



endif # QRTR

net/qrtr/Makefile

+3 −0
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@@ -8,3 +8,6 @@ qrtr-mhi-y := mhi.o 


obj-$(CONFIG_QRTR_USB) += qrtr-usb.o

qrtr-usb-y      := usb.o



obj-$(CONFIG_QRTR_FIFO) += qrtr-fifo.o

qrtr-fifo-y	:= fifo.o

net/qrtr/fifo.c

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+396 −0
Original line number Diff line number Diff line 
/*

 * Copyright (c) 2016, Linaro Ltd

 * Copyright (c) 2018, The Linux Foundation. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 and

 * only version 2 as published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 */



#include <linux/delay.h>

#include <linux/interrupt.h>

#include <linux/io.h>

#include <linux/of_device.h>

#include <linux/module.h>

#include <linux/platform_device.h>

#include <linux/types.h>

#include <linux/skbuff.h>

#include <linux/sched.h>

#include <microvisor/microvisor.h>



#include "qrtr.h"



#define FIFO_MAGIC_KEY 0x24495043 /* "$IPC" */

#define FIFO_SIZE 0x4000

#define FIFO_0_START 0x1000

#define FIFO_1_START (FIFO_0_START + FIFO_SIZE)

#define FIFO_MAGIC_IDX 0x0

#define TAIL_0_IDX 0x1

#define HEAD_0_IDX 0x2

#define TAIL_1_IDX 0x3

#define HEAD_1_IDX 0x4



struct fifo_pipe {

	__le32 *tail;

	__le32 *head;



	void *fifo;

	size_t length;

};



/**

 * qrtr_fifo_xprt - qrtr FIFO transport structure

 * @ep: qrtr endpoint specific info.

 * @tx_pipe: TX FIFO specific info.

 * @rx_pipe: RX FIFO specific info.

 * @fifo_base: Base of the shared FIFO.

 * @fifo_size: FIFO Size.

 * @tx_fifo_idx: TX FIFO index.

 * @kcap: Register info to raise irq to other VM.

 */

struct qrtr_fifo_xprt {

	struct qrtr_endpoint ep;

	struct fifo_pipe tx_pipe;

	struct fifo_pipe rx_pipe;

	void *fifo_base;

	size_t fifo_size;

	int tx_fifo_idx;

	okl4_kcap_t kcap;

};



static void qrtr_fifo_raise_virq(struct qrtr_fifo_xprt *xprtp);



static size_t fifo_rx_avail(struct fifo_pipe *pipe)

{

	u32 head;

	u32 tail;



	head = le32_to_cpu(*pipe->head);

	tail = le32_to_cpu(*pipe->tail);



	if (head < tail)

		return pipe->length - tail + head;



	return head - tail;

}



static void fifo_rx_peak(struct fifo_pipe *pipe,

			 void *data, unsigned int offset, size_t count)

{

	size_t len;

	u32 tail;



	tail = le32_to_cpu(*pipe->tail);

	tail += offset;

	if (tail >= pipe->length)

		tail -= pipe->length;



	len = min_t(size_t, count, pipe->length - tail);

	if (len)

		memcpy_fromio(data, pipe->fifo + tail, len);



	if (len != count)

		memcpy_fromio(data + len, pipe->fifo, (count - len));

}



static void fifo_rx_advance(struct fifo_pipe *pipe, size_t count)

{

	u32 tail;



	tail = le32_to_cpu(*pipe->tail);



	tail += count;

	if (tail > pipe->length)

		tail -= pipe->length;



	*pipe->tail = cpu_to_le32(tail);

}



static size_t fifo_tx_avail(struct fifo_pipe *pipe)

{

	u32 head;

	u32 tail;

	u32 avail;



	 head = le32_to_cpu(*pipe->head);

	 tail = le32_to_cpu(*pipe->tail);



	if (tail <= head)

		avail = pipe->length - head + tail;

	else

		avail = tail - head;



	return avail;

}



static void fifo_tx_write(struct fifo_pipe *pipe,

			  const void *data, size_t count)

{

	size_t len;

	u32 head;



	head = le32_to_cpu(*pipe->head);



	len = min_t(size_t, count, pipe->length - head);

	if (len)

		memcpy_toio(pipe->fifo + head, data, len);



	if (len != count)

		memcpy_toio(pipe->fifo, data + len, count - len);



	head += count;

	if (head >= pipe->length)

		head -= pipe->length;



	/* Ensure ordering of fifo and head update */

	wmb();



	*pipe->head = cpu_to_le32(head);

}



/* from qrtr to FIFO */

static int xprt_write(struct qrtr_endpoint *ep, struct sk_buff *skb)

{

	struct qrtr_fifo_xprt *xprtp;

	int rc;



	xprtp = container_of(ep, struct qrtr_fifo_xprt, ep);



	rc = skb_linearize(skb);

	if (rc) {

		kfree_skb(skb);

		return rc;

	}



	/* TODO: FIFO write : check if we can write full packet at one shot */

	if (fifo_tx_avail(&xprtp->tx_pipe) < skb->len) {

		pr_err("No Space in FIFO\n");

		return -EAGAIN;

	}



	fifo_tx_write(&xprtp->tx_pipe, skb->data, skb->len);

	kfree_skb(skb);



	qrtr_fifo_raise_virq(xprtp);



	return 0;

}



static void xprt_read_data(struct qrtr_fifo_xprt *xprtp)

{

	int rc;

	u32 hdr[8];

	void *data;

	size_t pkt_len;

	size_t rx_avail;

	size_t hdr_len = sizeof(hdr);



	while (fifo_rx_avail(&xprtp->rx_pipe)) {

		fifo_rx_peak(&xprtp->rx_pipe, &hdr, 0, hdr_len);

		pkt_len = qrtr_peek_pkt_size((void *)&hdr);



		if (pkt_len < 0) {

			pr_err("%s invalid pkt_len %zu\n", __func__, pkt_len);

			break;

		}



		data = kzalloc(pkt_len, GFP_ATOMIC);

		if (!data)

			break;



		rx_avail = fifo_rx_avail(&xprtp->rx_pipe);

		if (rx_avail < pkt_len) {

			pr_err("%s Not FULL pkt in FIFO %zu %zu\n",

			       __func__, rx_avail, pkt_len);

			break;

		}



		fifo_rx_peak(&xprtp->rx_pipe, data, 0, pkt_len);

		fifo_rx_advance(&xprtp->rx_pipe, pkt_len);



		rc = qrtr_endpoint_post(&xprtp->ep, data, pkt_len);

		if (rc == -EINVAL)

			pr_err("%s invalid ipcrouter packet\n", __func__);

		kfree(data);

		data = NULL;

	}

}



static void qrtr_fifo_raise_virq(struct qrtr_fifo_xprt *xprtp)

{

	okl4_error_t err;

	unsigned long payload = 0xffff;



	err = _okl4_sys_vinterrupt_raise(xprtp->kcap, payload);

}



static irqreturn_t qrtr_fifo_virq_handler(int irq, void *dev_id)

{

	xprt_read_data((struct qrtr_fifo_xprt *)dev_id);

	return IRQ_HANDLED;

}



/**

 * qrtr_fifo_config_init() - init FIFO xprt configs

 *

 * @return: 0 on success, standard Linux error codes on error.

 *

 * This function is called to initialize the FIFO XPRT pointer with

 * the FIFO XPRT configurations either from device tree or static arrays.

 */

static int qrtr_fifo_config_init(struct qrtr_fifo_xprt *xprtp)

{

	__le32 *descs;



	descs = xprtp->fifo_base;

	descs[FIFO_MAGIC_IDX] = FIFO_MAGIC_KEY;



	if (xprtp->tx_fifo_idx) {

		xprtp->tx_pipe.tail = &descs[TAIL_0_IDX];

		xprtp->tx_pipe.head = &descs[HEAD_0_IDX];

		xprtp->tx_pipe.fifo = xprtp->fifo_base + FIFO_0_START;

		xprtp->tx_pipe.length = FIFO_SIZE;



		xprtp->rx_pipe.tail = &descs[TAIL_1_IDX];

		xprtp->rx_pipe.head = &descs[HEAD_1_IDX];

		xprtp->rx_pipe.fifo = xprtp->fifo_base + FIFO_1_START;

		xprtp->rx_pipe.length = FIFO_SIZE;

	} else {

		xprtp->tx_pipe.tail = &descs[TAIL_1_IDX];

		xprtp->tx_pipe.head = &descs[HEAD_1_IDX];

		xprtp->tx_pipe.fifo = xprtp->fifo_base + FIFO_1_START;

		xprtp->tx_pipe.length = FIFO_SIZE;



		xprtp->rx_pipe.tail = &descs[TAIL_0_IDX];

		xprtp->rx_pipe.head = &descs[HEAD_0_IDX];

		xprtp->rx_pipe.fifo = xprtp->fifo_base + FIFO_0_START;

		xprtp->rx_pipe.length = FIFO_SIZE;

	}



	/* Reset respective index */

	*xprtp->tx_pipe.head = 0;

	*xprtp->rx_pipe.tail = 0;



	return 0;

}



/**

 * qrtr_fifo_xprt_probe() - Probe an FIFO xprt

 *

 * @pdev: Platform device corresponding to FIFO xprt.

 *

 * @return: 0 on success, standard Linux error codes on error.

 *

 * This function is called when the underlying device tree driver registers

 * a platform device, mapped to an FIFO transport.

 */

static int qrtr_fifo_xprt_probe(struct platform_device *pdev)

{

	int irq;

	int ret;

	struct resource *r;

	struct device *parent;

	struct qrtr_fifo_xprt *xprtp;

	struct device_node *ipc_irq_np;

	struct device_node *ipc_shm_np;

	struct platform_device *ipc_shm_dev;



	xprtp = devm_kzalloc(&pdev->dev, sizeof(*xprtp), GFP_KERNEL);

	if (!xprtp)

		return -ENOMEM;



	parent = &pdev->dev;

	ipc_irq_np = parent->of_node;



	irq = platform_get_irq(pdev, 0);

	if (irq < 0)

		return -ENODEV;



	ret = devm_request_irq(parent, irq, qrtr_fifo_virq_handler,

			       IRQF_TRIGGER_RISING, dev_name(parent),

			       xprtp);

	if (ret < 0)

		return -ENODEV;



	/* this kcap is required to raise VIRQ */

	ret = of_property_read_u32(ipc_irq_np, "reg", &xprtp->kcap);

	if (ret < 0)

		return -ENODEV;



	ipc_shm_np = of_parse_phandle(ipc_irq_np, "qcom,ipc-shm", 0);

	if (!ipc_shm_np)

		return -ENODEV;



	ipc_shm_dev = of_find_device_by_node(ipc_shm_np);

	if (!ipc_shm_dev)

		return -ENODEV;



	r = platform_get_resource(ipc_shm_dev, IORESOURCE_MEM, 0);

	if (!r) {

		pr_err("%s failed to get shared FIFO\n", __func__);

		return -ENODEV;

	}



	xprtp->tx_fifo_idx = of_property_read_bool(ipc_shm_np,

						   "qcom,tx-is-first");



	xprtp->fifo_size = resource_size(r);

	xprtp->fifo_base = devm_ioremap_nocache(&pdev->dev, r->start,

						resource_size(r));

	if (!xprtp->fifo_base) {

		pr_err("%s ioreamp_nocache() failed\n", __func__);

		return -ENOMEM;

	}



	ret = qrtr_fifo_config_init(xprtp);

	if (ret) {

		pr_err("%s init failed ret[%d]\n", __func__, ret);

		return ret;

	}



	xprtp->ep.xmit = xprt_write;

	ret = qrtr_endpoint_register(&xprtp->ep, QRTR_EP_NID_AUTO);

	if (ret)

		return ret;



	if (fifo_rx_avail(&xprtp->rx_pipe))

		xprt_read_data(xprtp);



	return 0;

}



static const struct of_device_id qrtr_fifo_xprt_match_table[] = {

	{ .compatible = "qcom,ipcr-fifo-xprt" },

	{},

};



static struct platform_driver qrtr_fifo_xprt_driver = {

	.probe = qrtr_fifo_xprt_probe,

	.driver = {

		.name = "qcom_fifo_qrtr",

		.owner = THIS_MODULE,

		.of_match_table = qrtr_fifo_xprt_match_table,

	 },

};



static int __init qrtr_fifo_xprt_init(void)

{

	int rc;



	rc = platform_driver_register(&qrtr_fifo_xprt_driver);

	if (rc) {

		pr_err("%s: driver register failed %d\n", __func__, rc);

		return rc;

	}



	return 0;

}



module_init(qrtr_fifo_xprt_init);

MODULE_DESCRIPTION("QTI IPC-router FIFO XPRT");

MODULE_LICENSE("GPL v2");