[PATCH 09/13] powerpc/5200: LocalPlus driver: smarter calculation of BPT, bytes per transfer

[Roman Fietze]

Signed-off-by: Roman Fietze <roman.fietze at telemotive.de>
---
 arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c |   33 +++++++++++++++----------
 1 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
index 48f2b4f..21b2a40 100644
--- a/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_lpbfifo.c
@@ -80,11 +80,11 @@ static inline int mpc52xx_lpbfifo_is_poll_dma(int flags)
  */
 static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request *req)
 {
-	size_t transfer_size = req->size - req->pos;
+	size_t tc = req->size - req->pos;
 	struct bcom_bd *bd;
 	void __iomem *reg;
 	u32 *data;
-	u32 bit_fields;
+	u32 control;
 	int rflags = req->flags;
 
 	/* Set and clear the reset bits; is good practice in User Manual */
@@ -93,10 +93,10 @@ static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request *req)
 	/* Set width, chip select and READ mode */
 	out_be32(&lpbfifo.regs->start_address, req->offset + req->pos);
 
-	/* Set CS and BPT */
-	bit_fields = MPC52xx_SCLPC_CONTROL_CS(req->cs) | 0x8;
+	/* Setup CS */
+	control = MPC52xx_SCLPC_CONTROL_CS(req->cs);
 	if (!(mpc52xx_lpbfifo_is_write(rflags)))
-		bit_fields |= MPC52xx_SCLPC_CONTROL_RWB_RECEIVE;	/* read mode */
+		control |= MPC52xx_SCLPC_CONTROL_RWB_RECEIVE;	/* read mode */
 
 	if (!mpc52xx_lpbfifo_is_dma(rflags)) {
 		/* While the FIFO can be setup for transfer sizes as
@@ -112,10 +112,10 @@ static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request *req)
 		 * The last block of data will be received with the
 		 * flush bit set. This avoids stale read data.
 		 */
-		if (transfer_size > 512)
-			transfer_size = 512;
+		if (tc > 512)
+			tc = 512;
 		else if (!(mpc52xx_lpbfifo_is_write(rflags)))
-			bit_fields |= MPC52xx_SCLPC_CONTROL_FLUSH;
+			control |= MPC52xx_SCLPC_CONTROL_FLUSH;
 
 		/* Load the FIFO with data */
 		if (mpc52xx_lpbfifo_is_write(rflags)) {
@@ -123,7 +123,7 @@ static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request *req)
 
 			reg = &lpbfifo.regs->fifo_data;
 			data = req->data + req->pos;
-			for (i = 0; i < transfer_size; i += 4)
+			for (i = 0; i < tc; i += 4)
 				out_be32(reg, *data++);
 		}
 
@@ -136,7 +136,7 @@ static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request *req)
 		/* In DMA mode we can always set the flush bit to avoid
 		 * stale read data. */
 		if (!(mpc52xx_lpbfifo_is_write(rflags)))
-			bit_fields |= MPC52xx_SCLPC_CONTROL_FLUSH;
+			control |= MPC52xx_SCLPC_CONTROL_FLUSH;
 
 		/* Choose the correct direction
 		 *
@@ -173,15 +173,17 @@ static void mpc52xx_lpbfifo_kick(struct mpc52xx_lpbfifo_request *req)
 		out_be32(&lpbfifo.regs->enable, MPC52xx_SCLPC_ENABLE_AIE | MPC52xx_SCLPC_ENABLE_NIE | MPC52xx_SCLPC_ENABLE_ME);
 
 		bd = bcom_prepare_next_buffer(lpbfifo.bcom_cur_task);
-		bd->status = transfer_size;
+		bd->status = tc;
 		bd->data[0] = req->data_dma + req->pos;
 		bcom_submit_next_buffer(lpbfifo.bcom_cur_task, NULL);
 	}
 
-	out_be32(&lpbfifo.regs->control, bit_fields);
+	/* Setup BPT. tc is already screened and a multiple of 4 */
+	control |= tc & 7 ? 4 : 8;
+	out_be32(&lpbfifo.regs->control, control);
 
 	/* Set packet size and kick it off */
-	out_be32(&lpbfifo.regs->packet_size.packet_size, MPC52xx_SCLPC_PACKET_SIZE_RESTART | transfer_size);
+	out_be32(&lpbfifo.regs->packet_size.packet_size, MPC52xx_SCLPC_PACKET_SIZE_RESTART | tc);
 	if (mpc52xx_lpbfifo_is_dma(rflags))
 		bcom_enable(lpbfifo.bcom_cur_task);
 }
@@ -395,6 +397,11 @@ int mpc52xx_lpbfifo_submit(struct mpc52xx_lpbfifo_request *req)
 	if (!lpbfifo.regs)
 		return -ENODEV;
 
+	/* The gen bd BestComm task currently only allows an increment
+	 * of 4 */
+	if (!req->size || req->size & 0x03)
+		return -EINVAL;
+
 	spin_lock_irqsave(&lpbfifo.lock, flags);
 
 	/* If the req pointer is already set, then a transfer is in progress */
-- 
1.6.5.5



-- 
Roman Fietze                Telemotive AG Büro Mühlhausen
Breitwiesen                              73347 Mühlhausen
Tel.: +49(0)7335/18493-45        http://www.telemotive.de