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20ea6adbf1
Build system: x86_64 Build-tested: bcm2708, bcm2709, bcm2710, bcm2711 Run-tested: bcm2708/RPiB+, bcm2709/RPi3B, bcm2710/RPi3B, bcm2711/RPi4B Signed-off-by: Marty Jones <mj8263788@gmail.com> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
92 lines
2.9 KiB
Diff
92 lines
2.9 KiB
Diff
From 0922abd923ec50f6cc41ded24485bd22c719c7bd Mon Sep 17 00:00:00 2001
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From: madimario <madimario@users.noreply.github.com>
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Date: Tue, 28 Sep 2021 04:20:06 -0400
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Subject: [PATCH] bcm2835_smi_dev: Fix handling of word-odd lengths
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The read and write functions did not use the correct pointer offset
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when dealing with an odd number of bytes after a DMA transfer. Also,
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only handle the remaining odd bytes if the DMA transfer completed
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successfully.
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Submitted-by: @madimario (GitHub)
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Signed-off-by: Phil Elwell <phil@raspberrypi.com>
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---
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drivers/char/broadcom/bcm2835_smi_dev.c | 21 ++++++++++++++-------
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1 file changed, 14 insertions(+), 7 deletions(-)
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--- a/drivers/char/broadcom/bcm2835_smi_dev.c
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+++ b/drivers/char/broadcom/bcm2835_smi_dev.c
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@@ -191,6 +191,7 @@ bcm2835_read_file(struct file *f, char _
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size_t count, loff_t *offs)
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{
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int odd_bytes;
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+ size_t count_check;
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dev_dbg(inst->dev, "User reading %zu bytes from SMI.", count);
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/* We don't want to DMA a number of bytes % 4 != 0 (32 bit FIFO) */
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@@ -199,6 +200,7 @@ bcm2835_read_file(struct file *f, char _
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else
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odd_bytes = count;
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count -= odd_bytes;
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+ count_check = count;
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if (count) {
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struct bcm2835_smi_bounce_info *bounce;
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@@ -209,15 +211,16 @@ bcm2835_read_file(struct file *f, char _
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count = dma_bounce_user(DMA_DEV_TO_MEM, user_ptr,
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count, bounce);
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}
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- if (odd_bytes) {
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+ if (odd_bytes && (count == count_check)) {
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/* Read from FIFO directly if not using DMA */
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uint8_t buf[DMA_THRESHOLD_BYTES];
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+ unsigned long bytes_not_transferred;
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bcm2835_smi_read_buf(smi_inst, buf, odd_bytes);
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- if (copy_to_user(user_ptr, buf, odd_bytes))
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+ bytes_not_transferred = copy_to_user(user_ptr + count, buf, odd_bytes);
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+ if (bytes_not_transferred)
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dev_err(inst->dev, "copy_to_user() failed.");
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- count += odd_bytes;
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-
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+ count += odd_bytes - bytes_not_transferred;
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}
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return count;
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}
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@@ -227,6 +230,7 @@ bcm2835_write_file(struct file *f, const
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size_t count, loff_t *offs)
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{
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int odd_bytes;
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+ size_t count_check;
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dev_dbg(inst->dev, "User writing %zu bytes to SMI.", count);
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if (count > DMA_THRESHOLD_BYTES)
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@@ -234,6 +238,7 @@ bcm2835_write_file(struct file *f, const
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else
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odd_bytes = count;
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count -= odd_bytes;
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+ count_check = count;
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if (count) {
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struct bcm2835_smi_bounce_info *bounce;
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@@ -245,14 +250,16 @@ bcm2835_write_file(struct file *f, const
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(char __user *)user_ptr,
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count, bounce);
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}
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- if (odd_bytes) {
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+ if (odd_bytes && (count == count_check)) {
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uint8_t buf[DMA_THRESHOLD_BYTES];
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+ unsigned long bytes_not_transferred;
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- if (copy_from_user(buf, user_ptr, odd_bytes))
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+ bytes_not_transferred = copy_from_user(buf, user_ptr + count, odd_bytes);
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+ if (bytes_not_transferred)
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dev_err(inst->dev, "copy_from_user() failed.");
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else
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bcm2835_smi_write_buf(smi_inst, buf, odd_bytes);
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- count += odd_bytes;
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+ count += odd_bytes - bytes_not_transferred;
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}
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return count;
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}
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