| 1 | From 4751c1c74bc7b596db5de0c93be1a22a570145c0 Mon Sep 17 00:00:00 2001 |
| 2 | From: Ernst Schwab <eschwab@online.de> |
| 3 | Date: Thu, 18 Feb 2010 12:47:46 +0100 |
| 4 | Subject: [PATCH] spi/mmc_spi: mmc_spi adaptations for SPI bus locking API |
| 5 | |
| 6 | Modification of the mmc_spi driver to use the SPI bus locking API. |
| 7 | With this, the mmc_spi driver can be used together with other SPI |
| 8 | devices on the same SPI bus. The exclusive access to the SPI bus is |
| 9 | now managed in the SPI layer. The counting of chip selects in the probe |
| 10 | function is no longer needed. |
| 11 | |
| 12 | Signed-off-by: Ernst Schwab <eschwab@online.de> |
| 13 | Signed-off-by: Grant Likely <grant.likely@secretlab.ca> |
| 14 | Tested-by: Matt Fleming <matt@console-pimps.org> |
| 15 | Tested-by: Antonio Ospite <ospite@studenti.unina.it> |
| 16 | --- |
| 17 | drivers/mmc/host/mmc_spi.c | 59 ++++++++----------------------------------- |
| 18 | 1 files changed, 11 insertions(+), 48 deletions(-) |
| 19 | |
| 20 | --- a/drivers/mmc/host/mmc_spi.c |
| 21 | +++ b/drivers/mmc/host/mmc_spi.c |
| 22 | @@ -181,7 +181,7 @@ mmc_spi_readbytes(struct mmc_spi_host *h |
| 23 | host->data_dma, sizeof(*host->data), |
| 24 | DMA_FROM_DEVICE); |
| 25 | |
| 26 | - status = spi_sync(host->spi, &host->readback); |
| 27 | + status = spi_sync_locked(host->spi, &host->readback); |
| 28 | |
| 29 | if (host->dma_dev) |
| 30 | dma_sync_single_for_cpu(host->dma_dev, |
| 31 | @@ -540,7 +540,7 @@ mmc_spi_command_send(struct mmc_spi_host |
| 32 | host->data_dma, sizeof(*host->data), |
| 33 | DMA_BIDIRECTIONAL); |
| 34 | } |
| 35 | - status = spi_sync(host->spi, &host->m); |
| 36 | + status = spi_sync_locked(host->spi, &host->m); |
| 37 | |
| 38 | if (host->dma_dev) |
| 39 | dma_sync_single_for_cpu(host->dma_dev, |
| 40 | @@ -684,7 +684,7 @@ mmc_spi_writeblock(struct mmc_spi_host * |
| 41 | host->data_dma, sizeof(*scratch), |
| 42 | DMA_BIDIRECTIONAL); |
| 43 | |
| 44 | - status = spi_sync(spi, &host->m); |
| 45 | + status = spi_sync_locked(spi, &host->m); |
| 46 | |
| 47 | if (status != 0) { |
| 48 | dev_dbg(&spi->dev, "write error (%d)\n", status); |
| 49 | @@ -821,7 +821,7 @@ mmc_spi_readblock(struct mmc_spi_host *h |
| 50 | DMA_FROM_DEVICE); |
| 51 | } |
| 52 | |
| 53 | - status = spi_sync(spi, &host->m); |
| 54 | + status = spi_sync_locked(spi, &host->m); |
| 55 | |
| 56 | if (host->dma_dev) { |
| 57 | dma_sync_single_for_cpu(host->dma_dev, |
| 58 | @@ -1017,7 +1017,7 @@ mmc_spi_data_do(struct mmc_spi_host *hos |
| 59 | host->data_dma, sizeof(*scratch), |
| 60 | DMA_BIDIRECTIONAL); |
| 61 | |
| 62 | - tmp = spi_sync(spi, &host->m); |
| 63 | + tmp = spi_sync_locked(spi, &host->m); |
| 64 | |
| 65 | if (host->dma_dev) |
| 66 | dma_sync_single_for_cpu(host->dma_dev, |
| 67 | @@ -1083,6 +1083,9 @@ static void mmc_spi_request(struct mmc_h |
| 68 | } |
| 69 | #endif |
| 70 | |
| 71 | + /* request exclusive bus access */ |
| 72 | + spi_bus_lock(host->spi->master); |
| 73 | + |
| 74 | /* issue command; then optionally data and stop */ |
| 75 | status = mmc_spi_command_send(host, mrq, mrq->cmd, mrq->data != NULL); |
| 76 | if (status == 0 && mrq->data) { |
| 77 | @@ -1093,6 +1096,9 @@ static void mmc_spi_request(struct mmc_h |
| 78 | mmc_cs_off(host); |
| 79 | } |
| 80 | |
| 81 | + /* release the bus */ |
| 82 | + spi_bus_unlock(host->spi->master); |
| 83 | + |
| 84 | mmc_request_done(host->mmc, mrq); |
| 85 | } |
| 86 | |
| 87 | @@ -1289,23 +1295,6 @@ mmc_spi_detect_irq(int irq, void *mmc) |
| 88 | return IRQ_HANDLED; |
| 89 | } |
| 90 | |
| 91 | -struct count_children { |
| 92 | - unsigned n; |
| 93 | - struct bus_type *bus; |
| 94 | -}; |
| 95 | - |
| 96 | -static int maybe_count_child(struct device *dev, void *c) |
| 97 | -{ |
| 98 | - struct count_children *ccp = c; |
| 99 | - |
| 100 | - if (dev->bus == ccp->bus) { |
| 101 | - if (ccp->n) |
| 102 | - return -EBUSY; |
| 103 | - ccp->n++; |
| 104 | - } |
| 105 | - return 0; |
| 106 | -} |
| 107 | - |
| 108 | static int mmc_spi_probe(struct spi_device *spi) |
| 109 | { |
| 110 | void *ones; |
| 111 | @@ -1337,32 +1326,6 @@ static int mmc_spi_probe(struct spi_devi |
| 112 | return status; |
| 113 | } |
| 114 | |
| 115 | - /* We can use the bus safely iff nobody else will interfere with us. |
| 116 | - * Most commands consist of one SPI message to issue a command, then |
| 117 | - * several more to collect its response, then possibly more for data |
| 118 | - * transfer. Clocking access to other devices during that period will |
| 119 | - * corrupt the command execution. |
| 120 | - * |
| 121 | - * Until we have software primitives which guarantee non-interference, |
| 122 | - * we'll aim for a hardware-level guarantee. |
| 123 | - * |
| 124 | - * REVISIT we can't guarantee another device won't be added later... |
| 125 | - */ |
| 126 | - if (spi->master->num_chipselect > 1) { |
| 127 | - struct count_children cc; |
| 128 | - |
| 129 | - cc.n = 0; |
| 130 | - cc.bus = spi->dev.bus; |
| 131 | - status = device_for_each_child(spi->dev.parent, &cc, |
| 132 | - maybe_count_child); |
| 133 | - if (status < 0) { |
| 134 | - dev_err(&spi->dev, "can't share SPI bus\n"); |
| 135 | - return status; |
| 136 | - } |
| 137 | - |
| 138 | - dev_warn(&spi->dev, "ASSUMING SPI bus stays unshared!\n"); |
| 139 | - } |
| 140 | - |
| 141 | /* We need a supply of ones to transmit. This is the only time |
| 142 | * the CPU touches these, so cache coherency isn't a concern. |
| 143 | * |
| 144 | |
