98 lines
3.0 KiB
Diff
98 lines
3.0 KiB
Diff
From 11aa9df4de06cc257327d783c5cb615989e87286 Mon Sep 17 00:00:00 2001
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From: Maxime Ripard <maxime.ripard@free-electrons.com>
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Date: Fri, 23 Jan 2015 15:18:27 +0100
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Subject: [PATCH v2 1/2] mtd: nand: pxa3xx: Fix PIO FIFO draining
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The NDDB register holds the data that are needed by the read and write
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commands.
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However, during a read PIO access, the datasheet specifies that after each 32
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bits read in that register, when BCH is enabled, we have to make sure that the
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RDDREQ bit is set in the NDSR register.
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This fixes an issue that was seen on the Armada 385, and presumably other mvebu
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SoCs, when a read on a newly erased page would end up in the driver reporting a
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timeout from the NAND.
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Cc: <stable@vger.kernel.org> # v3.14
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Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
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---
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drivers/mtd/nand/pxa3xx_nand.c | 45 ++++++++++++++++++++++++++++++++++++------
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1 file changed, 39 insertions(+), 6 deletions(-)
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diff --git a/drivers/mtd/nand/pxa3xx_nand.c b/drivers/mtd/nand/pxa3xx_nand.c
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index 96b0b1d27df1..e6918befb951 100644
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--- a/drivers/mtd/nand/pxa3xx_nand.c
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+++ b/drivers/mtd/nand/pxa3xx_nand.c
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@@ -23,6 +23,7 @@
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#include <linux/mtd/partitions.h>
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#include <linux/io.h>
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#include <linux/irq.h>
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+#include <linux/jiffies.h>
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#include <linux/slab.h>
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#include <linux/of.h>
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#include <linux/of_device.h>
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@@ -480,6 +481,38 @@ static void disable_int(struct pxa3xx_nand_info *info, uint32_t int_mask)
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nand_writel(info, NDCR, ndcr | int_mask);
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}
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+static void drain_fifo(struct pxa3xx_nand_info *info, void *data, int len)
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+{
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+ u32 *dst = (u32 *)data;
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+
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+ if (info->ecc_bch) {
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+ while (len--) {
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+ u32 timeout;
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+
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+ *dst++ = nand_readl(info, NDDB);
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+
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+ /*
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+ * According to the datasheet, when reading
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+ * from NDDB with BCH enabled, after each 32
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+ * bits reads, we have to make sure that the
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+ * NDSR.RDDREQ bit is set
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+ */
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+ timeout = jiffies + msecs_to_jiffies(5);
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+ while (!(nand_readl(info, NDSR) & NDSR_RDDREQ)) {
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+ if (!time_before(jiffies, timeout)) {
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+ dev_err(&info->pdev->dev,
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+ "Timeout on RDDREQ while draining the FIFO\n");
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+ return;
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+ }
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+
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+ cpu_relax();
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+ }
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+ }
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+ } else {
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+ __raw_readsl(info->mmio_base + NDDB, data, len);
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+ }
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+}
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+
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static void handle_data_pio(struct pxa3xx_nand_info *info)
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{
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unsigned int do_bytes = min(info->data_size, info->chunk_size);
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@@ -496,14 +529,14 @@ static void handle_data_pio(struct pxa3xx_nand_info *info)
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DIV_ROUND_UP(info->oob_size, 4));
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break;
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case STATE_PIO_READING:
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- __raw_readsl(info->mmio_base + NDDB,
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- info->data_buff + info->data_buff_pos,
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- DIV_ROUND_UP(do_bytes, 4));
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+ drain_fifo(info,
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+ info->data_buff + info->data_buff_pos,
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+ DIV_ROUND_UP(do_bytes, 4));
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if (info->oob_size > 0)
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- __raw_readsl(info->mmio_base + NDDB,
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- info->oob_buff + info->oob_buff_pos,
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- DIV_ROUND_UP(info->oob_size, 4));
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+ drain_fifo(info,
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+ info->oob_buff + info->oob_buff_pos,
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+ DIV_ROUND_UP(info->oob_size, 4));
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break;
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default:
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dev_err(&info->pdev->dev, "%s: invalid state %d\n", __func__,
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--
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2.2.2
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