Commit a7b221d8 authored by Rafał Miłecki's avatar Rafał Miłecki Committed by Mark Brown
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spi: bcm53xx: add spi_flash_read callback for MMIO-based reads 



This implements more efficient reads of SPI-attached flash content.

Signed-off-by: default avatarRafał Miłecki <zajec5@gmail.com>
Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent f55532a0

drivers/spi/spi-bcm53xx.c

+76 −2
Original line number Diff line number Diff line
@@ -10,6 +10,7 @@ 
#include "spi-bcm53xx.h"



#define BCM53XXSPI_MAX_SPI_BAUD	13500000	/* 216 MHz? */

#define BCM53XXSPI_FLASH_WINDOW	SZ_32M



/* The longest observed required wait was 19 ms */

#define BCM53XXSPI_SPE_TIMEOUT_MS	80
@@ -17,8 +18,10 @@ 
struct bcm53xxspi {

	struct bcma_device *core;

	struct spi_master *master;

	void __iomem *mmio_base;



	size_t read_offset;

	bool bspi;				/* Boot SPI mode with memory mapping */

};



static inline u32 bcm53xxspi_read(struct bcm53xxspi *b53spi, u16 offset)
@@ -32,6 +35,50 @@ static inline void bcm53xxspi_write(struct bcm53xxspi *b53spi, u16 offset, 
	bcma_write32(b53spi->core, offset, value);

}



static void bcm53xxspi_disable_bspi(struct bcm53xxspi *b53spi)

{

	struct device *dev = &b53spi->core->dev;

	unsigned long deadline;

	u32 tmp;



	if (!b53spi->bspi)

		return;



	tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL);

	if (tmp & 0x1)

		return;



	deadline = jiffies + usecs_to_jiffies(200);

	do {

		tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_BUSY_STATUS);

		if (!(tmp & 0x1)) {

			bcm53xxspi_write(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL,

					 0x1);

			ndelay(200);

			b53spi->bspi = false;

			return;

		}

		udelay(1);

	} while (!time_after_eq(jiffies, deadline));



	dev_warn(dev, "Timeout disabling BSPI\n");

}



static void bcm53xxspi_enable_bspi(struct bcm53xxspi *b53spi)

{

	u32 tmp;



	if (b53spi->bspi)

		return;



	tmp = bcm53xxspi_read(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL);

	if (!(tmp & 0x1))

		return;



	bcm53xxspi_write(b53spi, B53SPI_BSPI_MAST_N_BOOT_CTRL, 0x0);

	b53spi->bspi = true;

}



static inline unsigned int bcm53xxspi_calc_timeout(size_t len)

{

	/* Do some magic calculation based on length and buad. Add 10% and 1. */
@@ -176,6 +223,8 @@ static int bcm53xxspi_transfer_one(struct spi_master *master, 
	u8 *buf;

	size_t left;



	bcm53xxspi_disable_bspi(b53spi);



	if (t->tx_buf) {

		buf = (u8 *)t->tx_buf;

		left = t->len;
@@ -206,6 +255,22 @@ static int bcm53xxspi_transfer_one(struct spi_master *master, 
	return 0;

}



static int bcm53xxspi_flash_read(struct spi_device *spi,

				 struct spi_flash_read_message *msg)

{

	struct bcm53xxspi *b53spi = spi_master_get_devdata(spi->master);

	int ret = 0;



	if (msg->from + msg->len > BCM53XXSPI_FLASH_WINDOW)

		return -EINVAL;



	bcm53xxspi_enable_bspi(b53spi);

	memcpy_fromio(msg->buf, b53spi->mmio_base + msg->from, msg->len);

	msg->retlen = msg->len;



	return ret;

}



/**************************************************

 * BCMA

 **************************************************/
@@ -222,6 +287,7 @@ MODULE_DEVICE_TABLE(bcma, bcm53xxspi_bcma_tbl); 


static int bcm53xxspi_bcma_probe(struct bcma_device *core)

{

	struct device *dev = &core->dev;

	struct bcm53xxspi *b53spi;

	struct spi_master *master;

	int err;
@@ -231,7 +297,7 @@ static int bcm53xxspi_bcma_probe(struct bcma_device *core) 
		return -ENOTSUPP;

	}



	master = spi_alloc_master(&core->dev, sizeof(*b53spi));

	master = spi_alloc_master(dev, sizeof(*b53spi));

	if (!master)

		return -ENOMEM;
@@ -239,11 +305,19 @@ static int bcm53xxspi_bcma_probe(struct bcma_device *core) 
	b53spi->master = master;

	b53spi->core = core;



	if (core->addr_s[0])

		b53spi->mmio_base = devm_ioremap(dev, core->addr_s[0],

						 BCM53XXSPI_FLASH_WINDOW);

	b53spi->bspi = true;

	bcm53xxspi_disable_bspi(b53spi);



	master->transfer_one = bcm53xxspi_transfer_one;

	if (b53spi->mmio_base)

		master->spi_flash_read = bcm53xxspi_flash_read;



	bcma_set_drvdata(core, b53spi);



	err = devm_spi_register_master(&core->dev, master);

	err = devm_spi_register_master(dev, master);

	if (err) {

		spi_master_put(master);

		bcma_set_drvdata(core, NULL);