Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 2163ddd6 authored by Houston Hoffman's avatar Houston Hoffman
Browse files

NFC: qca199x: use coherent memory for i2c read 



I2C dma reads returned garbage on large reads for 64 bit systems. We
allocate coherent memory that persists for the life of the driver and
use it to buffer the dma access before coppying the data back out to
userspace.

Change-Id: I9369007f3ccc2904ef939b5e3d5934538bbd0b4d
Signed-off-by: default avatarHouston Hoffman <hhoffman@codeaurora.org>
parent 2f4a89d1

drivers/nfc/nfc-nci.c

+66 −5
Original line number Diff line number Diff line
@@ -27,6 +27,8 @@ 
#include <linux/of_device.h>

#include <linux/regulator/consumer.h>

#include "nfc-nci.h"

#include <linux/dma-mapping.h>

#include <linux/dmapool.h>



struct qca199x_platform_data {

	unsigned int irq_gpio;
@@ -45,8 +47,7 @@ static struct of_device_id msm_match_table[] = { 
};



MODULE_DEVICE_TABLE(of, msm_match_table);



#define MAX_BUFFER_SIZE			(780)

#define MAX_BUFFER_SIZE			(320)

#define PACKET_MAX_LENGTH		(258)

/* Read data */

#define PACKET_HEADER_SIZE_NCI	(4)
@@ -92,6 +93,9 @@ struct qca199x_dev { 
	bool			clk_run;

	struct work_struct	msm_clock_controll_work;

	struct workqueue_struct *my_wq;

	struct dma_pool *nfc_dma_pool;

	dma_addr_t dma_handle_physical_addr;

	void *dma_virtual_addr;

};



static int nfcc_reboot(struct notifier_block *notifier, unsigned long val,
@@ -246,7 +250,8 @@ static ssize_t nfc_read(struct file *filp, char __user *buf, 
					size_t count, loff_t *offset)

{

	struct qca199x_dev *qca199x_dev = filp->private_data;

	unsigned char tmp[MAX_BUFFER_SIZE], rd_byte;

	unsigned char rd_byte;

	unsigned char *tmp = NULL;

	unsigned char len[PAYLOAD_HEADER_LENGTH];

	int total, length, ret;

	int ftm_rerr_code;
@@ -258,7 +263,9 @@ static ssize_t nfc_read(struct file *filp, char __user *buf, 
		count = MAX_BUFFER_SIZE;



	mutex_lock(&qca199x_dev->read_mutex);

	memset(tmp, 0, sizeof(tmp));



	tmp = qca199x_dev->dma_virtual_addr;

	memset(tmp, 0, MAX_BUFFER_SIZE);

	memset(len, 0, sizeof(len));

	dmode = device_mode.handle_flavour;

	/* FTM-RAW-I2C RD/WR MODE - Special Case */
@@ -1232,6 +1239,32 @@ static int qca199x_probe(struct i2c_client *client, 
	}

	qca199x_dev->client = client;



	/* if coherent_dma_mask not set by the device, set it to ULONG_MAX */

	if (client->dev.coherent_dma_mask == 0)

		client->dev.coherent_dma_mask = ULONG_MAX;



	qca199x_dev->nfc_dma_pool = NULL;

	qca199x_dev->dma_virtual_addr = NULL;



	qca199x_dev->nfc_dma_pool = dma_pool_create("NFC-DMA", &client->dev,

						MAX_BUFFER_SIZE, 64, 4096);

	if (!qca199x_dev->nfc_dma_pool) {

		dev_err(&client->dev,

		"nfc-nci probe: failed to allocate memory for dma_pool\n");

		r = -ENOMEM;

		goto err_free_dev;

	}



	qca199x_dev->dma_virtual_addr = dma_pool_alloc(

				qca199x_dev->nfc_dma_pool, GFP_KERNEL,

				&qca199x_dev->dma_handle_physical_addr);

	if (!qca199x_dev->dma_virtual_addr) {

		dev_err(&client->dev,

		"nfc-nci probe: failed to allocate coherent memory for i2c dma buffer\n");

		r = -ENOMEM;

		goto err_free_dev;

	}



	/*

	 * To be efficient we need to test whether nfcc hardware is physically

	 * present before attempting further hardware initialisation.
@@ -1489,7 +1522,22 @@ err_irq: 
err_dis_gpio:

	gpio_free(platform_data->dis_gpio);

err_free_dev:

	if (!qca199x_dev->dma_virtual_addr) {

		dma_pool_free(qca199x_dev->nfc_dma_pool,

				qca199x_dev->dma_virtual_addr,

				qca199x_dev->dma_handle_physical_addr);



		qca199x_dev->dma_virtual_addr = NULL;

	}



	if (!qca199x_dev->nfc_dma_pool) {

		dma_pool_destroy(qca199x_dev->nfc_dma_pool);

		qca199x_dev->nfc_dma_pool = NULL;

	}





	kfree(qca199x_dev);



	return r;

}
@@ -1509,8 +1557,21 @@ static int qca199x_remove(struct i2c_client *client) 
	gpio_free(qca199x_dev->dis_gpio);

	if (strcmp(qca199x_dev->clk_src_name, "GPCLK2"))

		gpio_free(qca199x_dev->clkreq_gpio);

	kfree(qca199x_dev);



	if (!qca199x_dev->dma_virtual_addr) {

		dma_pool_free(qca199x_dev->nfc_dma_pool,

			qca199x_dev->dma_virtual_addr,

			qca199x_dev->dma_handle_physical_addr);



		qca199x_dev->dma_virtual_addr = NULL;

	}



	if (!qca199x_dev->nfc_dma_pool) {

		dma_pool_destroy(qca199x_dev->nfc_dma_pool);

		qca199x_dev->nfc_dma_pool = NULL;

	}



	kfree(qca199x_dev);

	return 0;

}