xilinx_spi: Switch to iomem functions and support little endian.

This patch changes the out_(be)(8|16|32) and in_(be)(8|16|32) calls to 32 bits ioread/iowrite.

The read and write function are attached to the internal struct as callbacks, callback
is selected depending on endianess.

This will also build on platforms not supporting the in/out calls for instance x86.

Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: John Linn <John.Linn@xilinx.com>
Signed-off-by: Richard Röjfors <richard.rojfors@mocean-labs.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

3 files changed, 57 insertions, 43 deletions

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index f34a2d16d18f..b528271c72ef 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -244,7 +244,7 @@ config SPI_TXX9
 
 config SPI_XILINX
         tristate "Xilinx SPI controller"
-        depends on EXPERIMENTAL
+        depends on HAS_IOMEM && EXPERIMENTAL
         select SPI_BITBANG
         select SPI_XILINX_OF if (XILINX_VIRTEX || MICROBLAZE)
         help
diff --git a/drivers/spi/xilinx_spi.c b/drivers/spi/xilinx_spi.c
index 69fa26d82ce4..135a3a5931a4 100644
--- a/drivers/spi/xilinx_spi.c
+++ b/drivers/spi/xilinx_spi.c
@@ -27,7 +27,7 @@
 /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
  * Product Specification", DS464
  */
-#define XSPI_CR_OFFSET          0x62    /* 16-bit Control Register */
+#define XSPI_CR_OFFSET          0x60    /* 16-bit Control Register */
 
 #define XSPI_CR_ENABLE          0x02
 #define XSPI_CR_MASTER_MODE     0x04
@@ -39,7 +39,7 @@
 #define XSPI_CR_MANUAL_SSELECT  0x80
 #define XSPI_CR_TRANS_INHIBIT   0x100
 
-#define XSPI_SR_OFFSET          0x67    /* 8-bit Status Register */
+#define XSPI_SR_OFFSET          0x64    /* 8-bit Status Register */
 
 #define XSPI_SR_RX_EMPTY_MASK   0x01    /* Receive FIFO is empty */
 #define XSPI_SR_RX_FULL_MASK    0x02    /* Receive FIFO is full */
@@ -47,8 +47,8 @@
 #define XSPI_SR_TX_FULL_MASK    0x08    /* Transmit FIFO is full */
 #define XSPI_SR_MODE_FAULT_MASK 0x10    /* Mode fault error */
 
-#define XSPI_TXD_OFFSET         0x6b    /* 8-bit Data Transmit Register */
-#define XSPI_RXD_OFFSET         0x6f    /* 8-bit Data Receive Register */
+#define XSPI_TXD_OFFSET         0x68    /* 8-bit Data Transmit Register */
+#define XSPI_RXD_OFFSET         0x6c    /* 8-bit Data Receive Register */
 
 #define XSPI_SSR_OFFSET         0x70    /* 32-bit Slave Select Register */
 
@@ -86,25 +86,29 @@ struct xilinx_spi {
         u8 *rx_ptr;             /* pointer in the Tx buffer */
         const u8 *tx_ptr;       /* pointer in the Rx buffer */
         int remaining_bytes;    /* the number of bytes left to transfer */
+        unsigned int (*read_fn) (void __iomem *);
+        void (*write_fn) (u32, void __iomem *);
 };
 
-static void xspi_init_hw(void __iomem *regs_base)
+static void xspi_init_hw(struct xilinx_spi *xspi)
 {
+        void __iomem *regs_base = xspi->regs;
+
         /* Reset the SPI device */
-        out_be32(regs_base + XIPIF_V123B_RESETR_OFFSET,
-                 XIPIF_V123B_RESET_MASK);
+        xspi->write_fn(XIPIF_V123B_RESET_MASK,
+                regs_base + XIPIF_V123B_RESETR_OFFSET);
         /* Disable all the interrupts just in case */
-        out_be32(regs_base + XIPIF_V123B_IIER_OFFSET, 0);
+        xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
         /* Enable the global IPIF interrupt */
-        out_be32(regs_base + XIPIF_V123B_DGIER_OFFSET,
-                 XIPIF_V123B_GINTR_ENABLE);
+        xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
+                regs_base + XIPIF_V123B_DGIER_OFFSET);
         /* Deselect the slave on the SPI bus */
-        out_be32(regs_base + XSPI_SSR_OFFSET, 0xffff);
+        xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
         /* Disable the transmitter, enable Manual Slave Select Assertion,
          * put SPI controller into master mode, and enable it */
-        out_be16(regs_base + XSPI_CR_OFFSET,
-                 XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT
-                 | XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE);
+        xspi->write_fn(XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT |
+                XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE,
+                regs_base + XSPI_CR_OFFSET);
 }
 
 static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
@@ -113,16 +117,16 @@ static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
 
         if (is_on == BITBANG_CS_INACTIVE) {
                 /* Deselect the slave on the SPI bus */
-                out_be32(xspi->regs + XSPI_SSR_OFFSET, 0xffff);
+                xspi->write_fn(0xffff, xspi->regs + XSPI_SSR_OFFSET);
         } else if (is_on == BITBANG_CS_ACTIVE) {
                 /* Set the SPI clock phase and polarity */
-                u16 cr = in_be16(xspi->regs + XSPI_CR_OFFSET)
+                u16 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET)
                          & ~XSPI_CR_MODE_MASK;
                 if (spi->mode & SPI_CPHA)
                         cr |= XSPI_CR_CPHA;
                 if (spi->mode & SPI_CPOL)
                         cr |= XSPI_CR_CPOL;
-                out_be16(xspi->regs + XSPI_CR_OFFSET, cr);
+                xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
 
                 /* We do not check spi->max_speed_hz here as the SPI clock
                  * frequency is not software programmable (the IP block design
@@ -130,8 +134,8 @@ static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
                  */
 
                 /* Activate the chip select */
-                out_be32(xspi->regs + XSPI_SSR_OFFSET,
-                         ~(0x0001 << spi->chip_select));
+                xspi->write_fn(~(0x0001 << spi->chip_select),
+                        xspi->regs + XSPI_SSR_OFFSET);
         }
 }
 
@@ -178,15 +182,15 @@ static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi)
         u8 sr;
 
         /* Fill the Tx FIFO with as many bytes as possible */
-        sr = in_8(xspi->regs + XSPI_SR_OFFSET);
+        sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
         while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) {
-                if (xspi->tx_ptr) {
-                        out_8(xspi->regs + XSPI_TXD_OFFSET, *xspi->tx_ptr++);
-                } else {
-                        out_8(xspi->regs + XSPI_TXD_OFFSET, 0);
-                }
+                if (xspi->tx_ptr)
+                        xspi->write_fn(*xspi->tx_ptr++,
+                                xspi->regs + XSPI_TXD_OFFSET);
+                else
+                        xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
                 xspi->remaining_bytes--;
-                sr = in_8(xspi->regs + XSPI_SR_OFFSET);
+                sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
         }
 }
 
@@ -208,18 +212,19 @@ static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
         /* Enable the transmit empty interrupt, which we use to determine
          * progress on the transmission.
          */
-        ipif_ier = in_be32(xspi->regs + XIPIF_V123B_IIER_OFFSET);
-        out_be32(xspi->regs + XIPIF_V123B_IIER_OFFSET,
-                 ipif_ier | XSPI_INTR_TX_EMPTY);
+        ipif_ier = xspi->read_fn(xspi->regs + XIPIF_V123B_IIER_OFFSET);
+        xspi->write_fn(ipif_ier | XSPI_INTR_TX_EMPTY,
+                xspi->regs + XIPIF_V123B_IIER_OFFSET);
 
         /* Start the transfer by not inhibiting the transmitter any longer */
-        cr = in_be16(xspi->regs + XSPI_CR_OFFSET) & ~XSPI_CR_TRANS_INHIBIT;
-        out_be16(xspi->regs + XSPI_CR_OFFSET, cr);
+        cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) &
+                ~XSPI_CR_TRANS_INHIBIT;
+        xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
 
         wait_for_completion(&xspi->done);
 
         /* Disable the transmit empty interrupt */
-        out_be32(xspi->regs + XIPIF_V123B_IIER_OFFSET, ipif_ier);
+        xspi->write_fn(ipif_ier, xspi->regs + XIPIF_V123B_IIER_OFFSET);
 
         return t->len - xspi->remaining_bytes;
 }
@@ -236,8 +241,8 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
         u32 ipif_isr;
 
         /* Get the IPIF interrupts, and clear them immediately */
-        ipif_isr = in_be32(xspi->regs + XIPIF_V123B_IISR_OFFSET);
-        out_be32(xspi->regs + XIPIF_V123B_IISR_OFFSET, ipif_isr);
+        ipif_isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
+        xspi->write_fn(ipif_isr, xspi->regs + XIPIF_V123B_IISR_OFFSET);
 
         if (ipif_isr & XSPI_INTR_TX_EMPTY) {    /* Transmission completed */
                 u16 cr;
@@ -248,20 +253,20 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
                  * transmitter while the Isr refills the transmit register/FIFO,
                  * or make sure it is stopped if we're done.
                  */
-                cr = in_be16(xspi->regs + XSPI_CR_OFFSET);
-                out_be16(xspi->regs + XSPI_CR_OFFSET,
-                         cr | XSPI_CR_TRANS_INHIBIT);
+                cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
+                xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
+                        xspi->regs + XSPI_CR_OFFSET);
 
                 /* Read out all the data from the Rx FIFO */
-                sr = in_8(xspi->regs + XSPI_SR_OFFSET);
+                sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
                 while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) {
                         u8 data;
 
-                        data = in_8(xspi->regs + XSPI_RXD_OFFSET);
+                        data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
                         if (xspi->rx_ptr) {
                                 *xspi->rx_ptr++ = data;
                         }
-                        sr = in_8(xspi->regs + XSPI_SR_OFFSET);
+                        sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
                 }
 
                 /* See if there is more data to send */
@@ -270,7 +275,7 @@ static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
                         /* Start the transfer by not inhibiting the
                          * transmitter any longer
                          */
-                        out_be16(xspi->regs + XSPI_CR_OFFSET, cr);
+                        xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
                 } else {
                         /* No more data to send.
                          * Indicate the transfer is completed.
@@ -325,9 +330,16 @@ struct spi_master *xilinx_spi_init(struct device *dev, struct resource *mem,
 
         xspi->mem = *mem;
         xspi->irq = irq;
+        if (pdata->little_endian) {
+                xspi->read_fn = ioread32;
+                xspi->write_fn = iowrite32;
+        } else {
+                xspi->read_fn = ioread32be;
+                xspi->write_fn = iowrite32be;
+        }
 
         /* SPI controller initializations */
-        xspi_init_hw(xspi->regs);
+        xspi_init_hw(xspi);
 
         /* Register for SPI Interrupt */
         ret = request_irq(xspi->irq, xilinx_spi_irq, 0, XILINX_SPI_NAME, xspi);
diff --git a/include/linux/spi/xilinx_spi.h b/include/linux/spi/xilinx_spi.h
index 06df0aba3aee..a705ad85eebe 100644
--- a/include/linux/spi/xilinx_spi.h
+++ b/include/linux/spi/xilinx_spi.h
@@ -4,11 +4,13 @@
 /**
  * struct xspi_platform_data - Platform data of the Xilinx SPI driver
  * @num_chipselect:     Number of chip select by the IP
+ * @little_endian       If registers should be accessed little endian or not
  * @devices:            Devices to add when the driver is probed.
  * @num_devices:        Number of devices in the devices array.
  */
 struct xspi_platform_data {
         u16 num_chipselect;
+        bool little_endian;
         struct spi_board_info *devices;
         u8 num_devices;
 };