>From 900dbad52b2cc88b46c5716b1afd22698f6d83aa Mon Sep 17 00:00:00 2001 From: Rob Ward <robert.ward...@googlemail.com> Date: Tue, 21 Oct 2014 17:46:53 +0100 Subject: [PATCH] mtd: phram: Allow multiple phram devices on cmd line
Allow the phram module the ability to create multiple phram mtd devices via the kernel command line. Currently the phram module only allows a single mtd device to be created via the kernel command line. This is due to the phram module having to store the values until it is initialised later. This storage is done using a single char[] meaning when the module_param_call is made the previous value is overidden. This change modifies the phram system to use a char[][] allowing multiple devices to be created. The array size if controlled using the new config option CONFIG_MTD_PHRAM_MAX_CMDLINE_ARGS that allows the maximum number of devices to be specified. Currently this option defaults to a value of 1 leaving the behaviour unchanged. If the array is full a message is printed to the console and the module_param_call returns. To test, in all cases an area of memory needs to be reserved via the command line e.g. memmap=10M$114M To test with phram build into the kernel on the command line add the following: phram.phram=alpha,114Mi,1Mi phram.phram=beta,115Mi,1Mi If CONFIG_MTD_PHRAM_MAX_CMDLINE_ARGS is left as default i.e. 1 then the first device, alpha will be created only. If the value of CONFIG_MTD_PHRAM_MAX_CMDLINE_ARGS is increased to 2 or more then both alpha and beta will be created. To test phram built as a module insmod with the following arguments: phram=gamma,114Mi,1Mi phram=delta,115Mi,1Mi In this case two devices should be created. Signed-off-by: Rob Ward <robert.ward...@googlemail.com> --- drivers/mtd/devices/Kconfig | 12 ++++++++++++ drivers/mtd/devices/phram.c | 39 ++++++++++++++++++++++++++++++++++----- 2 files changed, 46 insertions(+), 5 deletions(-) diff --git a/drivers/mtd/devices/Kconfig b/drivers/mtd/devices/Kconfig index c49d0b1..5fdc80b 100644 --- a/drivers/mtd/devices/Kconfig +++ b/drivers/mtd/devices/Kconfig @@ -136,6 +136,18 @@ config MTD_PHRAM doesn't have access to, memory beyond the mem=xxx limit, nvram, memory on the video card, etc... +config MTD_PHRAM_MAX_CMDLINE_ARGS + int "Max number of devices via Kernel command line" + depends on MTD_PHRAM=y + default 1 + help + Specify the number of phram devices that can be initialised + using the Kernel command line. + + This option is only applicable when phram is built into the + Kernel. When built as a module many devices can be specified + at module insmod. + config MTD_LART tristate "28F160xx flash driver for LART" depends on SA1100_LART diff --git a/drivers/mtd/devices/phram.c b/drivers/mtd/devices/phram.c index effd9a4..b42678e 100644 --- a/drivers/mtd/devices/phram.c +++ b/drivers/mtd/devices/phram.c @@ -212,9 +212,13 @@ static int phram_init_called; * - phram.phram=<device>,<address>,<size> for built-in case * We leave 64 bytes for the device name, 20 for the address and 20 for the * size. + * + * The maximum number of devices supported is controlled by the + * MTD_PHRAM_MAX_CMDLINE_ARGS config option + * * Example: phram.phram=rootfs,0xa0000000,512Mi */ -static char phram_paramline[64 + 20 + 20]; +static char phram_paramline[CONFIG_MTD_PHRAM_MAX_CMDLINE_ARGS][64 + 20 + 20]; #endif static int phram_setup(const char *val) @@ -271,6 +275,8 @@ static int phram_param_call(const char *val, struct kernel_param *kp) #ifdef MODULE return phram_setup(val); #else + int i; + /* * If more parameters are later passed in via * /sys/module/phram/parameters/phram @@ -290,9 +296,25 @@ static int phram_param_call(const char *val, struct kernel_param *kp) * phram_setup(). */ - if (strlen(val) >= sizeof(phram_paramline)) + if (strlen(val) >= sizeof(phram_paramline[0])) return -ENOSPC; - strcpy(phram_paramline, val); + + /* + * Check if any space is left in the array. If no space + * is left then print warning and return 0 + */ + + if (phram_paramline[ARRAY_SIZE(phram_paramline) - 1][0]) { + pr_warn("exceeded limit via cmd_line - %s ignored", val); + return 0; + } + + for (i = 0; i < ARRAY_SIZE(phram_paramline); i++) { + if (!phram_paramline[i][0]) { + strcpy(phram_paramline[i], val); + break; + } + } return 0; #endif @@ -307,8 +329,15 @@ static int __init init_phram(void) int ret = 0; #ifndef MODULE - if (phram_paramline[0]) - ret = phram_setup(phram_paramline); + int i; + + for (i = 0; i < ARRAY_SIZE(phram_paramline); i++) { + if (phram_paramline[i][0]) { + ret = phram_setup(phram_paramline[i]); + if (ret) + break; + } + } phram_init_called = 1; #endif -- 2.0.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/