bcm53xx: replace SPI revert with a fix sent upstream
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:
parent
d24bdaa794
commit
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2 changed files with 42 additions and 146 deletions
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@ -0,0 +1,42 @@
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Date: Thu, 11 Oct 2018 09:07:31 +0200
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Subject: [PATCH FIX] spi: bcm-qspi: switch back to reading flash using smaller
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chunks
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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Fixing/optimizing bcm_qspi_bspi_read() performance introduced two
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changes:
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1) It added a loop to read all requested data using multiple BSPI ops.
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2) It bumped max size of a single BSPI block request from 256 to 512 B.
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The later change resulted in occasional BSPI timeouts causing a
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regression.
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For some unknown reason hardware doesn't always handle reads as expected
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when using 512 B chunks. In such cases it may happen that BSPI returns
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amount of requested bytes without the last 1-3 ones. It provides the
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remaining bytes later but doesn't raise an interrupt until another LR
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start.
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Switching back to 256 B reads fixes that problem and regression.
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Fixes: 345309fa7c0c ("spi: bcm-qspi: Fix bcm_qspi_bspi_read() performance")
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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Cc: stable@vger.kernel.org # 4.11+
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---
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drivers/spi/spi-bcm-qspi.c | 2 +-
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1 file changed, 1 insertion(+), 1 deletion(-)
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--- a/drivers/spi/spi-bcm-qspi.c
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+++ b/drivers/spi/spi-bcm-qspi.c
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@@ -88,7 +88,7 @@
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#define BSPI_BPP_MODE_SELECT_MASK BIT(8)
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#define BSPI_BPP_ADDR_SELECT_MASK BIT(16)
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-#define BSPI_READ_LENGTH 512
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+#define BSPI_READ_LENGTH 256
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/* MSPI register offsets */
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#define MSPI_SPCR0_LSB 0x000
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@ -1,146 +0,0 @@
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From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
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Subject: [PATCH] Revert "spi: bcm-qspi: Fix bcm_qspi_bspi_read() performance"
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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This reverts commit 345309fa7c0c9206a5344d379b174499952d79d9.
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BSPI reads became unstable starting with above commit. There are BSPI
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timeouts like this:
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[ 15.637809] bcm_iproc 18029200.spi: timeout waiting for BSPI
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(...)
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[ 15.997809] bcm_iproc 18029200.spi: timeout waiting for BSPI
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which cause filesystem stability problems.
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Before above commit every time that bcm_qspi_bspi_lr_l2_isr() called
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bcm_qspi_bspi_lr_l2_isr() it was resulting in bspi_rf_msg_len becoming
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0.
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With that change it's not the case anymore which suggests there may be
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some bug around that code.
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It has changed and the new behavior seems to be causing problems.
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Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
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---
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--- a/drivers/spi/spi-bcm-qspi.c
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+++ b/drivers/spi/spi-bcm-qspi.c
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@@ -88,7 +88,7 @@
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#define BSPI_BPP_MODE_SELECT_MASK BIT(8)
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#define BSPI_BPP_ADDR_SELECT_MASK BIT(16)
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-#define BSPI_READ_LENGTH 512
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+#define BSPI_READ_LENGTH 256
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/* MSPI register offsets */
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#define MSPI_SPCR0_LSB 0x000
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@@ -806,7 +806,7 @@ static int bcm_qspi_bspi_flash_read(stru
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struct spi_flash_read_message *msg)
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{
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struct bcm_qspi *qspi = spi_master_get_devdata(spi->master);
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- u32 addr = 0, len, rdlen, len_words;
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+ u32 addr = 0, len, len_words;
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int ret = 0;
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unsigned long timeo = msecs_to_jiffies(100);
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struct bcm_qspi_soc_intc *soc_intc = qspi->soc_intc;
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@@ -819,7 +819,7 @@ static int bcm_qspi_bspi_flash_read(stru
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bcm_qspi_write(qspi, MSPI, MSPI_WRITE_LOCK, 0);
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/*
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- * when using flex mode we need to send
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+ * when using flex mode mode we need to send
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* the upper address byte to bspi
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*/
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if (bcm_qspi_bspi_ver_three(qspi) == false) {
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@@ -833,56 +833,47 @@ static int bcm_qspi_bspi_flash_read(stru
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else
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addr = msg->from & 0x00ffffff;
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+ /* set BSPI RAF buffer max read length */
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+ len = msg->len;
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+ if (len > BSPI_READ_LENGTH)
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+ len = BSPI_READ_LENGTH;
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+
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if (bcm_qspi_bspi_ver_three(qspi) == true)
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addr = (addr + 0xc00000) & 0xffffff;
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- /*
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- * read into the entire buffer by breaking the reads
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- * into RAF buffer read lengths
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- */
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- len = msg->len;
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+ reinit_completion(&qspi->bspi_done);
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+ bcm_qspi_enable_bspi(qspi);
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+ len_words = (len + 3) >> 2;
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+ qspi->bspi_rf_msg = msg;
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+ qspi->bspi_rf_msg_status = 0;
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qspi->bspi_rf_msg_idx = 0;
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+ qspi->bspi_rf_msg_len = len;
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+ dev_dbg(&qspi->pdev->dev, "bspi xfr addr 0x%x len 0x%x", addr, len);
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- do {
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- if (len > BSPI_READ_LENGTH)
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- rdlen = BSPI_READ_LENGTH;
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- else
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- rdlen = len;
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-
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- reinit_completion(&qspi->bspi_done);
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- bcm_qspi_enable_bspi(qspi);
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- len_words = (rdlen + 3) >> 2;
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- qspi->bspi_rf_msg = msg;
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- qspi->bspi_rf_msg_status = 0;
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- qspi->bspi_rf_msg_len = rdlen;
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- dev_dbg(&qspi->pdev->dev,
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- "bspi xfr addr 0x%x len 0x%x", addr, rdlen);
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- bcm_qspi_write(qspi, BSPI, BSPI_RAF_START_ADDR, addr);
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- bcm_qspi_write(qspi, BSPI, BSPI_RAF_NUM_WORDS, len_words);
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- bcm_qspi_write(qspi, BSPI, BSPI_RAF_WATERMARK, 0);
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- if (qspi->soc_intc) {
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- /*
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- * clear soc MSPI and BSPI interrupts and enable
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- * BSPI interrupts.
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- */
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- soc_intc->bcm_qspi_int_ack(soc_intc, MSPI_BSPI_DONE);
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- soc_intc->bcm_qspi_int_set(soc_intc, BSPI_DONE, true);
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- }
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+ bcm_qspi_write(qspi, BSPI, BSPI_RAF_START_ADDR, addr);
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+ bcm_qspi_write(qspi, BSPI, BSPI_RAF_NUM_WORDS, len_words);
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+ bcm_qspi_write(qspi, BSPI, BSPI_RAF_WATERMARK, 0);
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+
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+ if (qspi->soc_intc) {
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+ /*
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+ * clear soc MSPI and BSPI interrupts and enable
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+ * BSPI interrupts.
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+ */
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+ soc_intc->bcm_qspi_int_ack(soc_intc, MSPI_BSPI_DONE);
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+ soc_intc->bcm_qspi_int_set(soc_intc, BSPI_DONE, true);
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+ }
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- /* Must flush previous writes before starting BSPI operation */
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- mb();
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- bcm_qspi_bspi_lr_start(qspi);
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- if (!wait_for_completion_timeout(&qspi->bspi_done, timeo)) {
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- dev_err(&qspi->pdev->dev, "timeout waiting for BSPI\n");
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- ret = -ETIMEDOUT;
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- break;
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- }
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+ /* Must flush previous writes before starting BSPI operation */
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+ mb();
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- /* set msg return length */
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- msg->retlen += rdlen;
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- addr += rdlen;
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- len -= rdlen;
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- } while (len);
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+ bcm_qspi_bspi_lr_start(qspi);
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+ if (!wait_for_completion_timeout(&qspi->bspi_done, timeo)) {
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+ dev_err(&qspi->pdev->dev, "timeout waiting for BSPI\n");
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+ ret = -ETIMEDOUT;
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+ } else {
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+ /* set the return length for the caller */
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+ msg->retlen = len;
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+ }
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return ret;
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}
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