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Subject[PATCH for-next] spi: bcm53xx: add spi_flash_read callback for MMIO-based reads
Date
This implements more efficient reads of SPI-attached flash content.

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
---
drivers/spi/spi-bcm53xx.c | 73 +++++++++++++++++++++++++++++++++++++++++++++--
1 file changed, 71 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-bcm53xx.c b/drivers/spi/spi-bcm53xx.c
index cc3f938..3bc7b77 100644
--- a/drivers/spi/spi-bcm53xx.c
+++ b/drivers/spi/spi-bcm53xx.c
@@ -17,8 +17,10 @@
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 +34,50 @@ 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 +222,8 @@ 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 +254,19 @@ 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;
+
+ bcm53xxspi_enable_bspi(b53spi);
+ memcpy_fromio(msg->buf, b53spi->mmio_base + msg->from, msg->len);
+ msg->retlen = msg->len;
+
+ return ret;
+}
+
/**************************************************
* BCMA
**************************************************/
@@ -222,6 +283,7 @@ 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 +293,7 @@ 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 +301,18 @@ 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], SZ_32M);
+ 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);
--
1.8.4.5
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