stmmac: improve and up-to-date the documentation

This patch adds new information for the driver
especially about its platform structure fields.
Signed-off-by: Giuseppe Cavallaro <peppe.cavallaro@st.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/networking/stmmac.txt

@@ -7,7 +7,7 @@ This is the driver for the MAC 10/100/1000 on-chip Ethernet controllers
 (Synopsys IP blocks); it has been fully tested on STLinux platforms.
 
 Currently this network device driver is for all STM embedded MAC/GMAC
-(7xxx SoCs). Other platforms start using it i.e. ARM SPEAr.
+(i.e. 7xxx/5xxx SoCs) and it's known working on other platforms i.e. ARM SPEAr.
 
 DWC Ether MAC 10/100/1000 Universal version 3.41a and DWC Ether MAC 10/100
 Universal version 4.0 have been used for developing the first code
@@ -71,7 +71,7 @@ Several performance tests on STM platforms showed this optimisation allows to sp
 the CPU while having the maximum throughput.
 
 4.4) WOL
-Wake up on Lan feature through Magic Frame is only supported for the GMAC
+Wake up on Lan feature through Magic and Unicast frames are supported for the GMAC
 core.
 
 4.5) DMA descriptors
@@ -91,11 +91,15 @@ LRO is not supported.
 The driver is compatible with PAL to work with PHY and GPHY devices.
 
 4.9) Platform information
-Several information came from the platform; please refer to the
-driver's Header file in include/linux directory.
+Several driver's information can be passed through the platform
+These are included in the include/linux/stmmac.h header file
+and detailed below as well:
 
-struct plat_stmmacenet_data {
+ struct plat_stmmacenet_data {
 	int bus_id;
+	int phy_addr;
+	int interface;
+	struct stmmac_mdio_bus_data *mdio_bus_data;
 	int pbl;
 	int clk_csr;
 	int has_gmac;
@@ -103,67 +107,135 @@ struct plat_stmmacenet_data {
 	int tx_coe;
 	int bugged_jumbo;
 	int pmt;
+	int force_sf_dma_mode;
 	void (*fix_mac_speed)(void *priv, unsigned int speed);
-        void (*bus_setup)(unsigned long ioaddr);
-#ifdef CONFIG_STM_DRIVERS
-        struct stm_pad_config *pad_config;
-#endif
+	void (*bus_setup)(void __iomem *ioaddr);
+	int (*init)(struct platform_device *pdev);
+	void (*exit)(struct platform_device *pdev);
 	void *bsp_priv;
-};
+ };
 
 Where:
-- pbl (Programmable Burst Length) is maximum number of
-  beats to be transferred in one DMA transaction.
+ o bus_id: bus identifier.
+ o phy_addr: the physical address can be passed from the platform.
+	    If it is set to -1 the driver will automatically
+	    detect it at run-time by probing all the 32 addresses.
+ o interface: PHY device's interface.
+ o mdio_bus_data: specific platform fields for the MDIO bus.
+ o pbl: the Programmable Burst Length is maximum number of beats to
+       be transferred in one DMA transaction.
        GMAC also enables the 4xPBL by default.
-- fix_mac_speed and bus_setup are used to configure internal target
-  registers (on STM platforms);
-- has_gmac: GMAC core is on board (get it at run-time in the next step);
-- bus_id: bus identifier.
-- tx_coe: core is able to perform the tx csum in HW.
-- enh_desc: if sets the MAC will use the enhanced descriptor structure.
-- clk_csr: CSR Clock range selection.
-- bugged_jumbo: some HWs are not able to perform the csum in HW for
-  over-sized frames due to limited buffer sizes. Setting this
-  flag the csum will be done in SW on JUMBO frames.
-
-struct plat_stmmacphy_data {
+ o clk_csr: CSR Clock range selection.
+ o has_gmac: uses the GMAC core.
+ o enh_desc: if sets the MAC will use the enhanced descriptor structure.
+ o tx_coe: core is able to perform the tx csum in HW.
+ o bugged_jumbo: some HWs are not able to perform the csum in HW for
+		over-sized frames due to limited buffer sizes.
+		Setting this flag the csum will be done in SW on
+		JUMBO frames.
+ o pmt: core has the embedded power module (optional).
+ o force_sf_dma_mode: force DMA to use the Store and Forward mode
+		     instead of the Threshold.
+ o fix_mac_speed: this callback is used for modifying some syscfg registers
+		 (on ST SoCs) according to the link speed negotiated by the
+		 physical layer .
+ o bus_setup: perform HW setup of the bus. For example, on some ST platforms
+	     this field is used to configure the AMBA  bridge to generate more
+	     efficient STBus traffic.
+ o init/exit: callbacks used for calling a custom initialisation;
+	     this is sometime necessary on some platforms (e.g. ST boxes)
+	     where the HW needs to have set some PIO lines or system cfg
+	     registers.
+ o custom_cfg: this is a custom configuration that can be passed while
+	      initialising the resources.
+
+The we have:
+
+ struct stmmac_mdio_bus_data {
 	int bus_id;
-        int phy_addr;
-        unsigned int phy_mask;
-        int interface;
 	int (*phy_reset)(void *priv);
-        void *priv;
-};
+	unsigned int phy_mask;
+	int *irqs;
+	int probed_phy_irq;
+ };
 
 Where:
-- bus_id: bus identifier;
-- phy_addr: physical address used for the attached phy device;
-            set it to -1 to get it at run-time;
-- interface: physical MII interface mode;
-- phy_reset: hook to reset HW function.
-
-SOURCES:
-- Kconfig
-- Makefile
-- stmmac_main.c: main network device driver;
-- stmmac_mdio.c: mdio functions;
-- stmmac_ethtool.c: ethtool support;
-- stmmac_timer.[ch]: timer code used for mitigating the driver dma interrupts
+ o bus_id: bus identifier;
+ o phy_reset: hook to reset the phy device attached to the bus.
+ o phy_mask: phy mask passed when register the MDIO bus within the driver.
+ o irqs: list of IRQs, one per PHY.
+ o probed_phy_irq: if irqs is NULL, use this for probed PHY.
+
+Below an example how the structures above are using on ST platforms.
+
+ static struct plat_stmmacenet_data stxYYY_ethernet_platform_data = {
+	.pbl = 32,
+	.has_gmac = 0,
+	.enh_desc = 0,
+	.fix_mac_speed = stxYYY_ethernet_fix_mac_speed,
+				|
+				|-> to write an internal syscfg
+				|   on this platform when the
+				|   link speed changes from 10 to
+				|   100 and viceversa
+	.init = &stmmac_claim_resource,
+				|
+				|-> On ST SoC this calls own "PAD"
+				|   manager framework to claim
+				|   all the resources necessary
+				|   (GPIO ...). The .custom_cfg field
+				|   is used to pass a custom config.
+};
+
+Below the usage of the stmmac_mdio_bus_data: on this SoC, in fact,
+there are two MAC cores: one MAC is for MDIO Bus/PHY emulation
+with fixed_link support.
+
+static struct stmmac_mdio_bus_data stmmac1_mdio_bus = {
+	.bus_id = 1,
+		|
+		|-> phy device on the bus_id 1
+	.phy_reset = phy_reset;
+		|
+		|-> function to provide the phy_reset on this board
+	.phy_mask = 0,
+};
+
+static struct fixed_phy_status stmmac0_fixed_phy_status = {
+	.link = 1,
+	.speed = 100,
+	.duplex = 1,
+};
+
+During the board's device_init we can configure the first
+MAC for fixed_link by calling:
+  fixed_phy_add(PHY_POLL, 1, &stmmac0_fixed_phy_status));)
+and the second one, with a real PHY device attached to the bus,
+by using the stmmac_mdio_bus_data structure (to provide the id, the
+reset procedure etc).
+
+4.10) List of source files:
+ o Kconfig
+ o Makefile
+ o stmmac_main.c: main network device driver;
+ o stmmac_mdio.c: mdio functions;
+ o stmmac_ethtool.c: ethtool support;
+ o stmmac_timer.[ch]: timer code used for mitigating the driver dma interrupts
 		      Only tested on ST40 platforms based.
-- stmmac.h: private driver structure;
-- common.h: common definitions and VFTs;
-- descs.h: descriptor structure definitions;
-- dwmac1000_core.c: GMAC core functions;
-- dwmac1000_dma.c:  dma functions for the GMAC chip;
-- dwmac1000.h: specific header file for the GMAC;
-- dwmac100_core: MAC 100 core and dma code;
-- dwmac100_dma.c: dma funtions for the MAC chip;
-- dwmac1000.h: specific header file for the MAC;
-- dwmac_lib.c: generic DMA functions shared among chips
-- enh_desc.c: functions for handling enhanced descriptors
-- norm_desc.c: functions for handling normal descriptors
-
-TODO:
-- XGMAC controller is not supported.
-- Review the timer optimisation code to use an embedded device that seems to be
+ o stmmac.h: private driver structure;
+ o common.h: common definitions and VFTs;
+ o descs.h: descriptor structure definitions;
+ o dwmac1000_core.c: GMAC core functions;
+ o dwmac1000_dma.c:  dma functions for the GMAC chip;
+ o dwmac1000.h: specific header file for the GMAC;
+ o dwmac100_core: MAC 100 core and dma code;
+ o dwmac100_dma.c: dma funtions for the MAC chip;
+ o dwmac1000.h: specific header file for the MAC;
+ o dwmac_lib.c: generic DMA functions shared among chips
+ o enh_desc.c: functions for handling enhanced descriptors
+ o norm_desc.c: functions for handling normal descriptors
+
+5) TODO:
+ o XGMAC is not supported.
+ o Review the timer optimisation code to use an embedded device that will be
   available in new chip generations.