From: Grant Likely <grant.lik...@arm.com> The MDIO state machine has a moderate amount of duplicate code in the state processing that can be consolidated. This patch does so and reorganizes it a bit so that far less code is required. Most of the states simply stream a fixed number of bits in as a single integer and can be handled by a common processing function that checks for completion of the state and returns the streamed in value.
Changes include: - Move clock state change tracking into core code - Use a common shift register for clocking data in and out - Create separate mdc & mdio accessor functions - will be replaced with GPIO connection in a follow-on patch Signed-off-by: Grant Likely <grant.lik...@arm.com> Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org> [PMD: just rebased] --- include/hw/net/mdio.h | 41 ++++++++------- hw/net/etraxfs_eth.c | 11 ++-- hw/net/mdio.c | 140 ++++++++++++++++++++++---------------------------- 3 files changed, 87 insertions(+), 105 deletions(-) diff --git a/include/hw/net/mdio.h b/include/hw/net/mdio.h index ed1879a728..7fca19784e 100644 --- a/include/hw/net/mdio.h +++ b/include/hw/net/mdio.h @@ -52,37 +52,33 @@ #define PHY_ADVERTISE_100FULL 0x0100 /* Try for 100mbps full-duplex */ struct qemu_phy { - uint32_t regs[NUM_PHY_REGS]; + uint16_t regs[NUM_PHY_REGS]; const uint16_t *regs_readonly_mask; /* 0=writable, 1=read-only */ - int link; + bool link; - unsigned int (*read)(struct qemu_phy *phy, unsigned int req); - void (*write)(struct qemu_phy *phy, unsigned int req, unsigned int data); + uint16_t (*read)(struct qemu_phy *phy, unsigned int req); + void (*write)(struct qemu_phy *phy, unsigned int req, uint16_t data); }; struct qemu_mdio { - /* bus. */ - int mdc; - int mdio; - - /* decoder. */ + /* bitbanging state machine */ + bool mdc; + bool mdio; enum { PREAMBLE, - SOF, OPC, ADDR, REQ, TURNAROUND, DATA } state; - unsigned int drive; - unsigned int cnt; - unsigned int addr; - unsigned int opc; - unsigned int req; - unsigned int data; + uint16_t cnt; /* Bit count for current state */ + uint16_t addr; /* PHY Address; retrieved during ADDR state */ + uint16_t opc; /* Operation; 2:read */ + uint16_t req; /* Register address */ + uint32_t shiftreg; /* shift register; bits in to or out from PHY */ struct qemu_phy *devs[32]; }; @@ -91,7 +87,16 @@ void mdio_phy_init(struct qemu_phy *phy, uint16_t id1, uint16_t id2); void mdio_attach(struct qemu_mdio *bus, struct qemu_phy *phy, unsigned int addr); uint16_t mdio_read_req(struct qemu_mdio *bus, uint8_t addr, uint8_t req); -void mdio_write_req(struct qemu_mdio *bus, uint8_t addr, uint8_t req, uint16_t data); -void mdio_cycle(struct qemu_mdio *bus); +void mdio_write_req(struct qemu_mdio *bus, uint8_t addr, uint8_t req, + uint16_t data); +void mdio_bitbang_set_clk(struct qemu_mdio *bus, bool mdc); +static inline void mdio_bitbang_set_data(struct qemu_mdio *bus, bool mdio) +{ + bus->mdio = mdio; +} +static inline bool mdio_bitbang_get_data(struct qemu_mdio *bus) +{ + return bus->mdio; +} #endif diff --git a/hw/net/etraxfs_eth.c b/hw/net/etraxfs_eth.c index 4c5415771f..1b518ea16e 100644 --- a/hw/net/etraxfs_eth.c +++ b/hw/net/etraxfs_eth.c @@ -119,7 +119,7 @@ eth_read(void *opaque, hwaddr addr, unsigned int size) switch (addr) { case R_STAT: - r = eth->mdio_bus.mdio & 1; + r = mdio_bitbang_get_data(ð->mdio_bus); break; default: r = eth->regs[addr]; @@ -177,13 +177,10 @@ eth_write(void *opaque, hwaddr addr, case RW_MGM_CTRL: /* Attach an MDIO/PHY abstraction. */ if (value & 2) { - eth->mdio_bus.mdio = value & 1; + mdio_bitbang_set_data(ð->mdio_bus, value & 1); } - if (eth->mdio_bus.mdc != (value & 4)) { - mdio_cycle(ð->mdio_bus); - eth_validate_duplex(eth); - } - eth->mdio_bus.mdc = !!(value & 4); + mdio_bitbang_set_clk(ð->mdio_bus, value & 4); + eth_validate_duplex(eth); eth->regs[addr] = value; break; diff --git a/hw/net/mdio.c b/hw/net/mdio.c index 89a6a3a590..96e10fada0 100644 --- a/hw/net/mdio.c +++ b/hw/net/mdio.c @@ -43,7 +43,7 @@ * linux driver (PHYID and Diagnostics reg). * TODO: Add friendly names for the register nums. */ -static unsigned int mdio_phy_read(struct qemu_phy *phy, unsigned int req) +static uint16_t mdio_phy_read(struct qemu_phy *phy, unsigned int req) { int regnum; unsigned r = 0; @@ -107,7 +107,8 @@ static unsigned int mdio_phy_read(struct qemu_phy *phy, unsigned int req) return r; } -static void mdio_phy_write(struct qemu_phy *phy, unsigned int req, unsigned int data) +static void mdio_phy_write(struct qemu_phy *phy, unsigned int req, + uint16_t data) { int regnum = req & 0x1f; uint16_t mask = phy->regs_readonly_mask[regnum]; @@ -136,13 +137,14 @@ void mdio_phy_init(struct qemu_phy *phy, uint16_t id1, uint16_t id2) /* Autonegotiation advertisement reg. */ phy->regs[PHY_AUTONEG_ADV] = 0x01e1; phy->regs_readonly_mask = default_readonly_mask; - phy->link = 1; + phy->link = true; phy->read = mdio_phy_read; phy->write = mdio_phy_write; } -void mdio_attach(struct qemu_mdio *bus, struct qemu_phy *phy, unsigned int addr) +void mdio_attach(struct qemu_mdio *bus, struct qemu_phy *phy, + unsigned int addr) { bus->devs[addr & 0x1f] = phy; } @@ -169,99 +171,77 @@ void mdio_write_req(struct qemu_mdio *bus, uint8_t addr, uint8_t req, } } -void mdio_cycle(struct qemu_mdio *bus) +/** + * mdio_bitbang_update() - internal function to check how many clocks have + * passed and move to the next state if necessary. Returns TRUE on state change. + */ +static bool mdio_bitbang_update(struct qemu_mdio *bus, int num_bits, int next, + uint16_t *reg) { + if (bus->cnt < num_bits) { + return false; + } + if (reg) { + *reg = bus->shiftreg; + } + bus->state = next; + bus->cnt = 0; + bus->shiftreg = 0; + return true; +} + +/** + * mdio_bitbang_set_clk() - set value of mdc signal and update state + */ +void mdio_bitbang_set_clk(struct qemu_mdio *bus, bool mdc) +{ + uint16_t tmp; + + if (mdc == bus->mdc) { + return; /* Clock state hasn't changed; do nothing */ + } + + bus->mdc = mdc; + if (bus->mdc) { + /* Falling (inactive) clock edge */ + if ((bus->state == DATA) && (bus->opc == 2)) { + bus->mdio = !!(bus->shiftreg & 0x8000); + } + return; + } + + /* Rising clock Edge */ + bus->shiftreg = (bus->shiftreg << 1) | bus->mdio; bus->cnt++; - D(printf("mdc=%d mdio=%d state=%d cnt=%d drv=%d\n", - bus->mdc, bus->mdio, bus->state, bus->cnt, bus->drive)); + bus->mdc, bus->mdio, bus->state, bus->cnt)); switch (bus->state) { case PREAMBLE: - if (bus->mdc) { - if (bus->cnt >= (32 * 2) && !bus->mdio) { - bus->cnt = 0; - bus->state = SOF; - bus->data = 0; - } - } - break; - case SOF: - if (bus->mdc) { - if (bus->mdio != 1) { - printf("WARNING: no SOF\n"); - } - if (bus->cnt == 1 * 2) { - bus->cnt = 0; - bus->opc = 0; - bus->state = OPC; - } + /* MDIO must be 30 clocks high, 1 low, and 1 high to get out of + preamble */ + if (bus->shiftreg == 0xfffffffd) { + mdio_bitbang_update(bus, 0, OPC, NULL); } break; case OPC: - if (bus->mdc) { - bus->opc <<= 1; - bus->opc |= bus->mdio & 1; - if (bus->cnt == 2 * 2) { - bus->cnt = 0; - bus->addr = 0; - bus->state = ADDR; - } - } + mdio_bitbang_update(bus, 2, ADDR, &bus->opc); break; case ADDR: - if (bus->mdc) { - bus->addr <<= 1; - bus->addr |= bus->mdio & 1; - - if (bus->cnt == 5 * 2) { - bus->cnt = 0; - bus->req = 0; - bus->state = REQ; - } - } + mdio_bitbang_update(bus, 5, REQ, &bus->addr); break; case REQ: - if (bus->mdc) { - bus->req <<= 1; - bus->req |= bus->mdio & 1; - if (bus->cnt == 5 * 2) { - bus->cnt = 0; - bus->state = TURNAROUND; - } - } + mdio_bitbang_update(bus, 5, TURNAROUND, &bus->req); break; case TURNAROUND: - if (bus->mdc && bus->cnt == 2 * 2) { - bus->mdio = 0; - bus->cnt = 0; - - if (bus->opc == 2) { - bus->drive = 1; - bus->data = mdio_read_req(bus, bus->addr, bus->req); - bus->mdio = bus->data & 1; - } - bus->state = DATA; + /* If beginning of DATA READ cycle, then read PHY into shift register */ + if (mdio_bitbang_update(bus, 2, DATA, NULL) && (bus->opc == 2)) { + bus->shiftreg = mdio_read_req(bus, bus->addr, bus->req); } break; case DATA: - if (!bus->mdc) { - if (bus->drive) { - bus->mdio = !!(bus->data & (1 << 15)); - bus->data <<= 1; - } - } else { - if (!bus->drive) { - bus->data <<= 1; - bus->data |= bus->mdio; - } - if (bus->cnt == 16 * 2) { - bus->cnt = 0; - bus->state = PREAMBLE; - if (!bus->drive) { - mdio_write_req(bus, bus->addr, bus->req, bus->data); - } - bus->drive = 0; - } + /* If end of DATA WRITE cycle, then write shift register to PHY */ + if (mdio_bitbang_update(bus, 16, PREAMBLE, &tmp) && (bus->opc == 1)) { + mdio_write_req(bus, bus->addr, bus->req, tmp); } break; default: -- 2.14.1