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bcm53xx: replace SPI revert with a fix sent upstream

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Instead of reverting whole commit it's enough to just revert a single
line change. It seems the real problem with the regressing commit was a
bump of read chunk size. Switching back to 256 B chunks is enough to fix
the problem/regression.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
This commit is contained in:
Rafał Miłecki
2018-10-11 10:01:45 +02:00
parent d24bdaa794
commit 92de28b751
2 changed files with 42 additions and 146 deletions
Download Patch File Download Diff File Expand all files Collapse all files

42
target/linux/bcm53xx/patches-4.14/180-spi-bcm-qspi-switch-back-to-reading-flash-using-smal.patch Normal file
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@@ -0,0 +1,42 @@
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Thu, 11 Oct 2018 09:07:31 +0200
Subject: [PATCH FIX] spi: bcm-qspi: switch back to reading flash using smaller
chunks
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Fixing/optimizing bcm_qspi_bspi_read() performance introduced two
changes:
1) It added a loop to read all requested data using multiple BSPI ops.
2) It bumped max size of a single BSPI block request from 256 to 512 B.
The later change resulted in occasional BSPI timeouts causing a
regression.
For some unknown reason hardware doesn't always handle reads as expected
when using 512 B chunks. In such cases it may happen that BSPI returns
amount of requested bytes without the last 1-3 ones. It provides the
remaining bytes later but doesn't raise an interrupt until another LR
start.
Switching back to 256 B reads fixes that problem and regression.
Fixes: 345309fa7c0c ("spi: bcm-qspi: Fix bcm_qspi_bspi_read() performance")
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Cc: stable@vger.kernel.org # 4.11+
---
drivers/spi/spi-bcm-qspi.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/spi/spi-bcm-qspi.c
+++ b/drivers/spi/spi-bcm-qspi.c
@@ -88,7 +88,7 @@
#define BSPI_BPP_MODE_SELECT_MASK BIT(8)
#define BSPI_BPP_ADDR_SELECT_MASK BIT(16)
-#define BSPI_READ_LENGTH 512
+#define BSPI_READ_LENGTH 256
/* MSPI register offsets */
#define MSPI_SPCR0_LSB 0x000

146
target/linux/bcm53xx/patches-4.14/800-Revert-spi-bcm-qspi-Fix-bcm_qspi_bspi_read-performan.patch
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@@ -1,146 +0,0 @@
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Subject: [PATCH] Revert "spi: bcm-qspi: Fix bcm_qspi_bspi_read() performance"
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
This reverts commit 345309fa7c0c9206a5344d379b174499952d79d9.
BSPI reads became unstable starting with above commit. There are BSPI
timeouts like this:
[ 15.637809] bcm_iproc 18029200.spi: timeout waiting for BSPI
(...)
[ 15.997809] bcm_iproc 18029200.spi: timeout waiting for BSPI
which cause filesystem stability problems.
Before above commit every time that bcm_qspi_bspi_lr_l2_isr() called
bcm_qspi_bspi_lr_l2_isr() it was resulting in bspi_rf_msg_len becoming
0.
With that change it's not the case anymore which suggests there may be
some bug around that code.
It has changed and the new behavior seems to be causing problems.
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
---
--- a/drivers/spi/spi-bcm-qspi.c
+++ b/drivers/spi/spi-bcm-qspi.c
@@ -88,7 +88,7 @@
#define BSPI_BPP_MODE_SELECT_MASK BIT(8)
#define BSPI_BPP_ADDR_SELECT_MASK BIT(16)
-#define BSPI_READ_LENGTH 512
+#define BSPI_READ_LENGTH 256
/* MSPI register offsets */
#define MSPI_SPCR0_LSB 0x000
@@ -806,7 +806,7 @@ static int bcm_qspi_bspi_flash_read(stru
struct spi_flash_read_message *msg)
{
struct bcm_qspi *qspi = spi_master_get_devdata(spi->master);
- u32 addr = 0, len, rdlen, len_words;
+ u32 addr = 0, len, len_words;
int ret = 0;
unsigned long timeo = msecs_to_jiffies(100);
struct bcm_qspi_soc_intc *soc_intc = qspi->soc_intc;
@@ -819,7 +819,7 @@ static int bcm_qspi_bspi_flash_read(stru
bcm_qspi_write(qspi, MSPI, MSPI_WRITE_LOCK, 0);
/*
- * when using flex mode we need to send
+ * when using flex mode mode we need to send
* the upper address byte to bspi
*/
if (bcm_qspi_bspi_ver_three(qspi) == false) {
@@ -833,56 +833,47 @@ static int bcm_qspi_bspi_flash_read(stru
else
addr = msg->from & 0x00ffffff;
+ /* set BSPI RAF buffer max read length */
+ len = msg->len;
+ if (len > BSPI_READ_LENGTH)
+ len = BSPI_READ_LENGTH;
+
if (bcm_qspi_bspi_ver_three(qspi) == true)
addr = (addr + 0xc00000) & 0xffffff;
- /*
- * read into the entire buffer by breaking the reads
- * into RAF buffer read lengths
- */
- len = msg->len;
+ reinit_completion(&qspi->bspi_done);
+ bcm_qspi_enable_bspi(qspi);
+ len_words = (len + 3) >> 2;
+ qspi->bspi_rf_msg = msg;
+ qspi->bspi_rf_msg_status = 0;
qspi->bspi_rf_msg_idx = 0;
+ qspi->bspi_rf_msg_len = len;
+ dev_dbg(&qspi->pdev->dev, "bspi xfr addr 0x%x len 0x%x", addr, len);
- do {
- if (len > BSPI_READ_LENGTH)
- rdlen = BSPI_READ_LENGTH;
- else
- rdlen = len;
-
- reinit_completion(&qspi->bspi_done);
- bcm_qspi_enable_bspi(qspi);
- len_words = (rdlen + 3) >> 2;
- qspi->bspi_rf_msg = msg;
- qspi->bspi_rf_msg_status = 0;
- qspi->bspi_rf_msg_len = rdlen;
- dev_dbg(&qspi->pdev->dev,
- "bspi xfr addr 0x%x len 0x%x", addr, rdlen);
- bcm_qspi_write(qspi, BSPI, BSPI_RAF_START_ADDR, addr);
- bcm_qspi_write(qspi, BSPI, BSPI_RAF_NUM_WORDS, len_words);
- bcm_qspi_write(qspi, BSPI, BSPI_RAF_WATERMARK, 0);
- if (qspi->soc_intc) {
- /*
- * clear soc MSPI and BSPI interrupts and enable
- * BSPI interrupts.
- */
- soc_intc->bcm_qspi_int_ack(soc_intc, MSPI_BSPI_DONE);
- soc_intc->bcm_qspi_int_set(soc_intc, BSPI_DONE, true);
- }
+ bcm_qspi_write(qspi, BSPI, BSPI_RAF_START_ADDR, addr);
+ bcm_qspi_write(qspi, BSPI, BSPI_RAF_NUM_WORDS, len_words);
+ bcm_qspi_write(qspi, BSPI, BSPI_RAF_WATERMARK, 0);
+
+ if (qspi->soc_intc) {
+ /*
+ * clear soc MSPI and BSPI interrupts and enable
+ * BSPI interrupts.
+ */
+ soc_intc->bcm_qspi_int_ack(soc_intc, MSPI_BSPI_DONE);
+ soc_intc->bcm_qspi_int_set(soc_intc, BSPI_DONE, true);
+ }
- /* Must flush previous writes before starting BSPI operation */
- mb();
- bcm_qspi_bspi_lr_start(qspi);
- if (!wait_for_completion_timeout(&qspi->bspi_done, timeo)) {
- dev_err(&qspi->pdev->dev, "timeout waiting for BSPI\n");
- ret = -ETIMEDOUT;
- break;
- }
+ /* Must flush previous writes before starting BSPI operation */
+ mb();
- /* set msg return length */
- msg->retlen += rdlen;
- addr += rdlen;
- len -= rdlen;
- } while (len);
+ bcm_qspi_bspi_lr_start(qspi);
+ if (!wait_for_completion_timeout(&qspi->bspi_done, timeo)) {
+ dev_err(&qspi->pdev->dev, "timeout waiting for BSPI\n");
+ ret = -ETIMEDOUT;
+ } else {
+ /* set the return length for the caller */
+ msg->retlen = len;
+ }
return ret;
}