spi: bcm53xx: add spi_flash_read callback for MMIO-based reads

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

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Signed-off-by: Mark Brown <broonie@kernel.org>

1 files changed, 76 insertions, 2 deletions

diff --git a/drivers/spi/spi-bcm53xx.c b/drivers/spi/spi-bcm53xx.c
index cc3f938f0a6b..afb51699dbb5 100644
--- a/drivers/spi/spi-bcm53xx.c
+++ b/drivers/spi/spi-bcm53xx.c
@@ -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);