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Date: Wed, 29 Mar 2017 12:43:22 -0500 From: Christopher Bostic <cbostic@...ux.vnet.ibm.com> To: robh+dt@...nel.org, mark.rutland@....com, linux@...linux.org.uk, rostedt@...dmis.org, mingo@...hat.com, gregkh@...uxfoundation.org, devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org Cc: Jeremy Kerr <jk@...abs.org>, joel@....id.au, linux-kernel@...r.kernel.org, andrew@...id.au, alistair@...ple.id.au, benh@...nel.crashing.org, Chris Bostic <cbostic@...ux.vnet.ibm.com> Subject: [PATCH v4 05/23] drivers/fsi: Add slave & master read/write APIs From: Jeremy Kerr <jk@...abs.org> Introduce functions to perform reads/writes on the slave address space; these simply pass the request on the slave's master with the correct link and slave ID. We implement these on top of similar helpers for the master. Signed-off-by: Jeremy Kerr <jk@...abs.org> Signed-off-by: Joel Stanley <joel@....id.au> Signed-off-by: Chris Bostic <cbostic@...ux.vnet.ibm.com> --- drivers/fsi/fsi-core.c | 92 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c index 4bbca95..32698ed 100644 --- a/drivers/fsi/fsi-core.c +++ b/drivers/fsi/fsi-core.c @@ -32,6 +32,11 @@ struct fsi_slave { #define to_fsi_slave(d) container_of(d, struct fsi_slave, dev) +static int fsi_master_read(struct fsi_master *master, int link, + uint8_t slave_id, uint32_t addr, void *val, size_t size); +static int fsi_master_write(struct fsi_master *master, int link, + uint8_t slave_id, uint32_t addr, const void *val, size_t size); + /* crc helpers */ static const uint8_t crc4_tab[] = { 0x0, 0x7, 0xe, 0x9, 0xb, 0xc, 0x5, 0x2, @@ -57,6 +62,58 @@ uint8_t fsi_crc4(uint8_t c, uint64_t x, int bits) EXPORT_SYMBOL_GPL(fsi_crc4); /* FSI slave support */ +static int fsi_slave_calc_addr(struct fsi_slave *slave, uint32_t *addrp, + uint8_t *idp) +{ + uint32_t addr = *addrp; + uint8_t id = *idp; + + if (addr > slave->size) + return -EINVAL; + + /* For 23 bit addressing, we encode the extra two bits in the slave + * id (and the slave's actual ID needs to be 0). + */ + if (addr > 0x1fffff) { + if (slave->id != 0) + return -EINVAL; + id = (addr >> 21) & 0x3; + addr &= 0x1fffff; + } + + *addrp = addr; + *idp = id; + return 0; +} + +static int fsi_slave_read(struct fsi_slave *slave, uint32_t addr, + void *val, size_t size) +{ + uint8_t id = slave->id; + int rc; + + rc = fsi_slave_calc_addr(slave, &addr, &id); + if (rc) + return rc; + + return fsi_master_read(slave->master, slave->link, id, + addr, val, size); +} + +static int fsi_slave_write(struct fsi_slave *slave, uint32_t addr, + const void *val, size_t size) +{ + uint8_t id = slave->id; + int rc; + + rc = fsi_slave_calc_addr(slave, &addr, &id); + if (rc) + return rc; + + return fsi_master_write(slave->master, slave->link, id, + addr, val, size); +} + static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id) { /* todo: initialise slave device, perform engine scan */ @@ -65,6 +122,41 @@ static int fsi_slave_init(struct fsi_master *master, int link, uint8_t id) } /* FSI master support */ +static int fsi_check_access(uint32_t addr, size_t size) +{ + if (size != 1 && size != 2 && size != 4) + return -EINVAL; + + if ((addr & 0x3) != (size & 0x3)) + return -EINVAL; + + return 0; +} + +static int fsi_master_read(struct fsi_master *master, int link, + uint8_t slave_id, uint32_t addr, void *val, size_t size) +{ + int rc; + + rc = fsi_check_access(addr, size); + if (rc) + return rc; + + return master->read(master, link, slave_id, addr, val, size); +} + +static int fsi_master_write(struct fsi_master *master, int link, + uint8_t slave_id, uint32_t addr, const void *val, size_t size) +{ + int rc; + + rc = fsi_check_access(addr, size); + if (rc) + return rc; + + return master->write(master, link, slave_id, addr, val, size); +} + static int fsi_master_scan(struct fsi_master *master) { int link; -- 1.8.2.2
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