target/linux/bcm53xx/patches-4.14/800-Revert-spi-bcm-qspi-Fix-bcm_qspi_bspi_read-performan.patch

   1 From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
   2 Subject: [PATCH] Revert "spi: bcm-qspi: Fix bcm_qspi_bspi_read() performance"
   3 MIME-Version: 1.0
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   6
   7 This reverts commit 345309fa7c0c9206a5344d379b174499952d79d9.
   8
   9 BSPI reads became unstable starting with above commit. There are BSPI
  10 timeouts like this:
  11 [   15.637809] bcm_iproc 18029200.spi: timeout waiting for BSPI
  12 (...)
  13 [   15.997809] bcm_iproc 18029200.spi: timeout waiting for BSPI
  14 which cause filesystem stability problems.
  15
  16 Before above commit every time that bcm_qspi_bspi_lr_l2_isr() called
  17 bcm_qspi_bspi_lr_l2_isr() it was resulting in bspi_rf_msg_len becoming
  18 0.
  19 With that change it's not the case anymore which suggests there may be
  20 some bug around that code.
  21
  22 It has changed and the new behavior seems to be causing problems.
  23
  24 Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
  25 ---
  26
  27 --- a/drivers/spi/spi-bcm-qspi.c
  28 +++ b/drivers/spi/spi-bcm-qspi.c
  29 @@ -88,7 +88,7 @@
  30  #define BSPI_BPP_MODE_SELECT_MASK              BIT(8)
  31  #define BSPI_BPP_ADDR_SELECT_MASK              BIT(16)
  32
  33 -#define BSPI_READ_LENGTH                       512
  34 +#define BSPI_READ_LENGTH                       256
  35
  36  /* MSPI register offsets */
  37  #define MSPI_SPCR0_LSB                         0x000
  38 @@ -806,7 +806,7 @@ static int bcm_qspi_bspi_flash_read(stru
  39                                     struct spi_flash_read_message *msg)
  40  {
  41         struct bcm_qspi *qspi = spi_master_get_devdata(spi->master);
  42 -       u32 addr = 0, len, rdlen, len_words;
  43 +       u32 addr = 0, len, len_words;
  44         int ret = 0;
  45         unsigned long timeo = msecs_to_jiffies(100);
  46         struct bcm_qspi_soc_intc *soc_intc = qspi->soc_intc;
  47 @@ -819,7 +819,7 @@ static int bcm_qspi_bspi_flash_read(stru
  48         bcm_qspi_write(qspi, MSPI, MSPI_WRITE_LOCK, 0);
  49
  50         /*
  51 -        * when using flex mode we need to send
  52 +        * when using flex mode mode we need to send
  53          * the upper address byte to bspi
  54          */
  55         if (bcm_qspi_bspi_ver_three(qspi) == false) {
  56 @@ -833,56 +833,47 @@ static int bcm_qspi_bspi_flash_read(stru
  57         else
  58                 addr = msg->from & 0x00ffffff;
  59
  60 +       /* set BSPI RAF buffer max read length */
  61 +       len = msg->len;
  62 +       if (len > BSPI_READ_LENGTH)
  63 +               len = BSPI_READ_LENGTH;
  64 +
  65         if (bcm_qspi_bspi_ver_three(qspi) == true)
  66                 addr = (addr + 0xc00000) & 0xffffff;
  67
  68 -       /*
  69 -        * read into the entire buffer by breaking the reads
  70 -        * into RAF buffer read lengths
  71 -        */
  72 -       len = msg->len;
  73 +       reinit_completion(&qspi->bspi_done);
  74 +       bcm_qspi_enable_bspi(qspi);
  75 +       len_words = (len + 3) >> 2;
  76 +       qspi->bspi_rf_msg = msg;
  77 +       qspi->bspi_rf_msg_status = 0;
  78         qspi->bspi_rf_msg_idx = 0;
  79 +       qspi->bspi_rf_msg_len = len;
  80 +       dev_dbg(&qspi->pdev->dev, "bspi xfr addr 0x%x len 0x%x", addr, len);
  81
  82 -       do {
  83 -               if (len > BSPI_READ_LENGTH)
  84 -                       rdlen = BSPI_READ_LENGTH;
  85 -               else
  86 -                       rdlen = len;
  87 -
  88 -               reinit_completion(&qspi->bspi_done);
  89 -               bcm_qspi_enable_bspi(qspi);
  90 -               len_words = (rdlen + 3) >> 2;
  91 -               qspi->bspi_rf_msg = msg;
  92 -               qspi->bspi_rf_msg_status = 0;
  93 -               qspi->bspi_rf_msg_len = rdlen;
  94 -               dev_dbg(&qspi->pdev->dev,
  95 -                       "bspi xfr addr 0x%x len 0x%x", addr, rdlen);
  96 -               bcm_qspi_write(qspi, BSPI, BSPI_RAF_START_ADDR, addr);
  97 -               bcm_qspi_write(qspi, BSPI, BSPI_RAF_NUM_WORDS, len_words);
  98 -               bcm_qspi_write(qspi, BSPI, BSPI_RAF_WATERMARK, 0);
  99 -               if (qspi->soc_intc) {
 100 -                       /*
 101 -                        * clear soc MSPI and BSPI interrupts and enable
 102 -                        * BSPI interrupts.
 103 -                        */
 104 -                       soc_intc->bcm_qspi_int_ack(soc_intc, MSPI_BSPI_DONE);
 105 -                       soc_intc->bcm_qspi_int_set(soc_intc, BSPI_DONE, true);
 106 -               }
 107 +       bcm_qspi_write(qspi, BSPI, BSPI_RAF_START_ADDR, addr);
 108 +       bcm_qspi_write(qspi, BSPI, BSPI_RAF_NUM_WORDS, len_words);
 109 +       bcm_qspi_write(qspi, BSPI, BSPI_RAF_WATERMARK, 0);
 110 +
 111 +       if (qspi->soc_intc) {
 112 +               /*
 113 +                * clear soc MSPI and BSPI interrupts and enable
 114 +                * BSPI interrupts.
 115 +                */
 116 +               soc_intc->bcm_qspi_int_ack(soc_intc, MSPI_BSPI_DONE);
 117 +               soc_intc->bcm_qspi_int_set(soc_intc, BSPI_DONE, true);
 118 +       }
 119
 120 -               /* Must flush previous writes before starting BSPI operation */
 121 -               mb();
 122 -               bcm_qspi_bspi_lr_start(qspi);
 123 -               if (!wait_for_completion_timeout(&qspi->bspi_done, timeo)) {
 124 -                       dev_err(&qspi->pdev->dev, "timeout waiting for BSPI\n");
 125 -                       ret = -ETIMEDOUT;
 126 -                       break;
 127 -               }
 128 +       /* Must flush previous writes before starting BSPI operation */
 129 +       mb();
 130
 131 -               /* set msg return length */
 132 -               msg->retlen += rdlen;
 133 -               addr += rdlen;
 134 -               len -= rdlen;
 135 -       } while (len);
 136 +       bcm_qspi_bspi_lr_start(qspi);
 137 +       if (!wait_for_completion_timeout(&qspi->bspi_done, timeo)) {
 138 +               dev_err(&qspi->pdev->dev, "timeout waiting for BSPI\n");
 139 +               ret = -ETIMEDOUT;
 140 +       } else {
 141 +               /* set the return length for the caller */
 142 +               msg->retlen = len;
 143 +       }
 144
 145         return ret;
 146  }