From 2822888c810eaf2d68271f4dac4a0ad639221fd3 Mon Sep 17 00:00:00 2001 From: Carl-Daniel Hailfinger Date: Wed, 15 Sep 2010 00:17:37 +0000 Subject: SPI bitbanging: request/release bus SPI bitbanging on devices which speak SPI natively has a dual-use problem: We need to shut down normal SPI operations to do the bitbanging ourselves. Once we're done, it makes a lot of sense to reenable "normal" SPI operations again. Add request_bus/release_bus functions to struct bitbang_spi_master. Add a bitbang shutdown function (not used yet). Change MCP SPI and Intel NIC SPI to use the new request/release bus infrastructure. Cosmetic changes to a few error messages (80 column limit). There are multiple possible strategies for bus request/release: - Request at the start of a SPI command, release immediately afterwards. - Request at the start of a SPI multicommand, release once all commands of the multicommand are done. - Request on programmer init, release on shutdown. Each strategy has its own advantages. For now, we will stay with the first strategy which worked fine so far. Corresponding to flashrom svn r1171. Signed-off-by: Carl-Daniel Hailfinger Acked-by: Uwe Hermann --- bitbang_spi.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 46 insertions(+), 2 deletions(-) (limited to 'bitbang_spi.c') diff --git a/bitbang_spi.c b/bitbang_spi.c index f697f5a..fe85b60 100644 --- a/bitbang_spi.c +++ b/bitbang_spi.c @@ -53,6 +53,18 @@ static int bitbang_spi_get_miso(void) return bitbang_spi_master->get_miso(); } +static void bitbang_spi_request_bus(void) +{ + if (bitbang_spi_master->request_bus) + bitbang_spi_master->request_bus(); +} + +static void bitbang_spi_release_bus(void) +{ + if (bitbang_spi_master->release_bus) + bitbang_spi_master->release_bus(); +} + int bitbang_spi_init(const struct bitbang_spi_master *master, int halfperiod) { /* BITBANG_SPI_INVALID is 0, so if someone forgot to initialize ->type, @@ -61,19 +73,44 @@ int bitbang_spi_init(const struct bitbang_spi_master *master, int halfperiod) */ if (!master || master->type == BITBANG_SPI_INVALID || !master->set_cs || !master->set_sck || !master->set_mosi || !master->get_miso) { - msg_perr("Incomplete bitbanging SPI master setting! Please " - "report a bug at flashrom@flashrom.org\n"); + msg_perr("Incomplete SPI bitbang master setting!\n" + "Please report a bug at flashrom@flashrom.org\n"); + return 1; + } + if (bitbang_spi_master) { + msg_perr("SPI bitbang master already initialized!\n" + "Please report a bug at flashrom@flashrom.org\n"); return 1; } + bitbang_spi_master = master; bitbang_spi_half_period = halfperiod; + /* FIXME: Run bitbang_spi_request_bus here or in programmer init? */ bitbang_spi_set_cs(1); bitbang_spi_set_sck(0); bitbang_spi_set_mosi(0); return 0; } +int bitbang_spi_shutdown(const struct bitbang_spi_master *master) +{ + if (!bitbang_spi_master) { + msg_perr("Shutting down an uninitialized SPI bitbang master!\n" + "Please report a bug at flashrom@flashrom.org\n"); + return 1; + } + if (master != bitbang_spi_master) { + msg_perr("Shutting down a mismatched SPI bitbang master!\n" + "Please report a bug at flashrom@flashrom.org\n"); + return 1; + } + + /* FIXME: Run bitbang_spi_release_bus here or per command? */ + bitbang_spi_master = NULL; + return 0; +} + static uint8_t bitbang_spi_readwrite_byte(uint8_t val) { uint8_t ret = 0; @@ -96,6 +133,11 @@ int bitbang_spi_send_command(unsigned int writecnt, unsigned int readcnt, { int i; + /* FIXME: Run bitbang_spi_request_bus here or in programmer init? + * Requesting and releasing the SPI bus is handled in here to allow the + * programmer to use its own SPI engine for native accesses. + */ + bitbang_spi_request_bus(); bitbang_spi_set_cs(0); for (i = 0; i < writecnt; i++) bitbang_spi_readwrite_byte(writearr[i]); @@ -105,6 +147,8 @@ int bitbang_spi_send_command(unsigned int writecnt, unsigned int readcnt, programmer_delay(bitbang_spi_half_period); bitbang_spi_set_cs(1); programmer_delay(bitbang_spi_half_period); + /* FIXME: Run bitbang_spi_release_bus here or in programmer init? */ + bitbang_spi_release_bus(); return 0; } -- cgit v1.1