pistachio: add kernel 4.14 support
[openwrt/openwrt.git] / target / linux / pistachio / patches-4.14 / 106-spi-img-spfi-finish-every-transfer-cleanly.patch
1 From 5fcca3fd4b621d7b5bdeca18d36dfc6ca6cfe383 Mon Sep 17 00:00:00 2001
2 From: Ionela Voinescu <ionela.voinescu@imgtec.com>
3 Date: Wed, 10 Aug 2016 11:42:26 +0100
4 Subject: spi: img-spfi: finish every transfer cleanly
5
6 Before this change, the interrupt status bit that signaled
7 the end of a tranfers was cleared in the wait_all_done
8 function. That functionality triggered issues for DMA
9 duplex transactions where the wait function was called
10 twice, in both the TX and RX callbacks.
11
12 In order to fix the issue, clear all interrupt data bits
13 at the end of a PIO transfer or at the end of both TX and RX
14 duplex transfers, if the transfer is not a pending tranfer
15 (command waiting for data). After that, the status register
16 is checked for new incoming data or new data requests to be
17 signaled. If SPFI finished cleanly, no new interrupt data
18 bits should be set.
19
20 Signed-off-by: Ionela Voinescu <ionela.voinescu@imgtec.com>
21 ---
22 drivers/spi/spi-img-spfi.c | 49 +++++++++++++++++++++++++++++++++-------------
23 1 file changed, 35 insertions(+), 14 deletions(-)
24
25 --- a/drivers/spi/spi-img-spfi.c
26 +++ b/drivers/spi/spi-img-spfi.c
27 @@ -83,6 +83,14 @@
28 #define SPFI_INTERRUPT_SDE BIT(1)
29 #define SPFI_INTERRUPT_SDTRIG BIT(0)
30
31 +#define SPFI_INTERRUPT_DATA_BITS (SPFI_INTERRUPT_SDHF |\
32 + SPFI_INTERRUPT_SDFUL |\
33 + SPFI_INTERRUPT_GDEX32BIT |\
34 + SPFI_INTERRUPT_GDHF |\
35 + SPFI_INTERRUPT_GDFUL |\
36 + SPFI_INTERRUPT_ALLDONETRIG |\
37 + SPFI_INTERRUPT_GDEX8BIT)
38 +
39 /*
40 * There are four parallel FIFOs of 16 bytes each. The word buffer
41 * (*_32BIT_VALID_DATA) accesses all four FIFOs at once, resulting in an
42 @@ -144,6 +152,23 @@ static inline void spfi_reset(struct img
43 spfi_writel(spfi, 0, SPFI_CONTROL);
44 }
45
46 +static inline void spfi_finish(struct img_spfi *spfi)
47 +{
48 + if (!(spfi->complete))
49 + return;
50 +
51 + /* Clear data bits as all transfers(TX and RX) have finished */
52 + spfi_writel(spfi, SPFI_INTERRUPT_DATA_BITS, SPFI_INTERRUPT_CLEAR);
53 + if (spfi_readl(spfi, SPFI_INTERRUPT_STATUS) & SPFI_INTERRUPT_DATA_BITS) {
54 + dev_err(spfi->dev, "SPFI did not finish transfer cleanly.\n");
55 + spfi_reset(spfi);
56 + }
57 + /* Disable SPFI for it not to interfere with pending transactions */
58 + spfi_writel(spfi,
59 + spfi_readl(spfi, SPFI_CONTROL) & ~SPFI_CONTROL_SPFI_EN,
60 + SPFI_CONTROL);
61 +}
62 +
63 static int spfi_wait_all_done(struct img_spfi *spfi)
64 {
65 unsigned long timeout = jiffies + msecs_to_jiffies(50);
66 @@ -152,19 +177,9 @@ static int spfi_wait_all_done(struct img
67 return 0;
68
69 while (time_before(jiffies, timeout)) {
70 - u32 status = spfi_readl(spfi, SPFI_INTERRUPT_STATUS);
71 -
72 - if (status & SPFI_INTERRUPT_ALLDONETRIG) {
73 - spfi_writel(spfi, SPFI_INTERRUPT_ALLDONETRIG,
74 - SPFI_INTERRUPT_CLEAR);
75 - /*
76 - * Disable SPFI for it not to interfere with
77 - * pending transactions
78 - */
79 - spfi_writel(spfi, spfi_readl(spfi, SPFI_CONTROL)
80 - & ~SPFI_CONTROL_SPFI_EN, SPFI_CONTROL);
81 + if (spfi_readl(spfi, SPFI_INTERRUPT_STATUS) &
82 + SPFI_INTERRUPT_ALLDONETRIG)
83 return 0;
84 - }
85 cpu_relax();
86 }
87
88 @@ -296,6 +311,8 @@ static int img_spfi_start_pio(struct spi
89 }
90
91 ret = spfi_wait_all_done(spfi);
92 + spfi_finish(spfi);
93 +
94 if (ret < 0)
95 return ret;
96
97 @@ -311,8 +328,10 @@ static void img_spfi_dma_rx_cb(void *dat
98
99 spin_lock_irqsave(&spfi->lock, flags);
100 spfi->rx_dma_busy = false;
101 - if (!spfi->tx_dma_busy)
102 + if (!spfi->tx_dma_busy) {
103 + spfi_finish(spfi);
104 spi_finalize_current_transfer(spfi->master);
105 + }
106 spin_unlock_irqrestore(&spfi->lock, flags);
107 }
108
109 @@ -325,8 +344,10 @@ static void img_spfi_dma_tx_cb(void *dat
110
111 spin_lock_irqsave(&spfi->lock, flags);
112 spfi->tx_dma_busy = false;
113 - if (!spfi->rx_dma_busy)
114 + if (!spfi->rx_dma_busy) {
115 + spfi_finish(spfi);
116 spi_finalize_current_transfer(spfi->master);
117 + }
118 spin_unlock_irqrestore(&spfi->lock, flags);
119 }
120