From fb45d3232c641bfee5000c8a81e2005903734702 Mon Sep 17 00:00:00 2001
From: Maxim Levitsky <maximlevitsky@gmail.com>
Date: Sat, 27 Feb 2010 02:04:02 +0200
Subject: [PATCH] mtd: r852: Few fixes for problems that occur when card is
rapidly inserted/removed.
First don't enable card detection logic to early. Second be very careful with
DMA engine, to be sure it doesn't write to kernel memory driver doesn't own.
Signed-off-by: Maxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
---
drivers/mtd/nand/r852.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)
diff --git a/drivers/mtd/nand/r852.c b/drivers/mtd/nand/r852.c
index 218a42dadff1..cb271167b4a5 100644
--- a/drivers/mtd/nand/r852.c
+++ b/drivers/mtd/nand/r852.c
@@ -96,14 +96,21 @@ static void r852_dma_enable(struct r852_device *dev)
if (dev->dma_dir)
dma_reg |= R852_DMA_READ;
- if (dev->dma_state == DMA_INTERNAL)
+ if (dev->dma_state == DMA_INTERNAL) {
dma_reg |= R852_DMA_INTERNAL;
- else {
+ /* Precaution to make sure HW doesn't write */
+ /* to random kernel memory */
+ r852_write_reg_dword(dev, R852_DMA_ADDR,
+ cpu_to_le32(dev->phys_bounce_buffer));
+ } else {
dma_reg |= R852_DMA_MEMORY;
r852_write_reg_dword(dev, R852_DMA_ADDR,
cpu_to_le32(dev->phys_dma_addr));
}
+ /* Precaution: make sure write reached the device */
+ r852_read_reg_dword(dev, R852_DMA_ADDR);
+
r852_write_reg_dword(dev, R852_DMA_SETTINGS, dma_reg);
/* Set dma irq */
@@ -129,6 +136,11 @@ static void r852_dma_done(struct r852_device *dev, int error)
r852_write_reg_dword(dev, R852_DMA_SETTINGS, 0);
r852_write_reg_dword(dev, R852_DMA_IRQ_ENABLE, 0);
+ /* Precaution to make sure HW doesn't write to random kernel memory */
+ r852_write_reg_dword(dev, R852_DMA_ADDR,
+ cpu_to_le32(dev->phys_bounce_buffer));
+ r852_read_reg_dword(dev, R852_DMA_ADDR);
+
dev->dma_error = error;
dev->dma_stage = 0;
@@ -579,6 +591,7 @@ void r852_card_update_present(struct r852_device *dev)
void r852_update_card_detect(struct r852_device *dev)
{
int card_detect_reg = r852_read_reg(dev, R852_CARD_IRQ_ENABLE);
+ dev->card_unstable = 0;
card_detect_reg &= ~(R852_CARD_IRQ_REMOVE | R852_CARD_IRQ_INSERT);
card_detect_reg |= R852_CARD_IRQ_GENABLE;
@@ -690,10 +703,10 @@ void r852_card_detect_work(struct work_struct *work)
struct r852_device *dev =
container_of(work, struct r852_device, card_detect_work.work);
- r852_update_card_detect(dev);
+ r852_card_update_present(dev);
dev->card_unstable = 0;
- /* false alarm */
+ /* False alarm */
if (dev->card_detected == dev->card_registred)
goto exit;